1.
Cusco
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Cuzco, often spelled Cusco, is a city in southeastern Peru, near the Urubamba Valley of the Andes mountain range. It is the capital of the Cusco Region as well as the Cusco Province, in 2013, the city had a population of 435,114. Located on the end of the Knot of Cuzco, its elevation is around 3,400 m. The site was the capital of the Inca Empire from the 13th until the 16th-century Spanish conquest. In 1983 Cusco was declared a World Heritage Site by UNESCO and it has become a major tourist destination, hosting nearly 2 million visitors a year. The Constitution of Peru designates it as the Historical Capital of Peru, the indigenous name of this city is Qusqu. Although the name was used in Quechua, its origin is found in the Aymara language, the word is derived from the phrase qusqu wanka, related to the citys foundation myth of the Ayar Siblings. According to this legend, Ayar Awqa acquired wings and flew to the site of the future city, there he was transformed into a rock to mark the possession of the land by his ayllu. Then Ayar Oche stood up, displayed a pair of large wings, then they went up on top of the hill. Now at the site where he was to remain as an idol and he returned and told Ayar Manco that from then on he was to be named Manco Capac. Ayar Oche came from where the Sun was and the Sun had ordered that Ayar Manco take that name, after this had been stated by the idol, Ayar Oche turned into a stone, just as he was, with his wings. Later Manco Capac went down with Ayar Auca to their settlement. he liked the place now occupied in this city Cuzco, Manco Capac and his companion, with the help of the four women, made a house. Having done this, Manco Capac and his companion, with the four women and it is said that they took the maize from the cave, which this lord Manco Capac named Pacaritambo, which means those of origin because. they came out of that cave. The Spanish conquistadors adopted the name, transliterating it into Spanish phonetics as Cuzco or, less often. Cuzco was the spelling on official documents and chronicles in colonial times. Cuzco, pronounced as in 16th-century Spanish, seems to have been an approximation to the Cusco Quechua pronunciation of the name at the time. As both Spanish and Quechuan pronunciation have evolved since then, the Spanish pronunciation of z is no longer close to the Quechuan pronunciation of the consonant represented by z in Cuzco. In 1976, the city signed an ordinance banning the traditional spelling and ordering the use of a new one, Cusco
2.
Mass wasting
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Types of mass wasting include creep, slides, flows, topples, and falls, each with its own characteristic features, and taking place over timescales from seconds to years. Mass wasting occurs on both terrestrial and submarine slopes, and has observed on Earth, Mars, Venus. When the gravitational force acting on a slope exceeds its resisting force, the slope materials strength and cohesion and the amount of internal friction between material help maintain the slopes stability and are known collectively as the slopes shear strength. The steepest angle that a slope can maintain without losing its stability is known as its angle of repose. When a slope made of loose material possesses this angle, its shear strength perfectly counterbalances the force of gravity acting upon it. Mass wasting may occur at a slow rate, particularly in areas that are very dry or those areas that receive sufficient rainfall such that vegetation has stabilized the surface. It may also occur at high speed, such as in rockslides or landslides, with disastrous consequences. Factors that change the potential of mass wasting include, change in angle, weakening of material by weathering, increased water content, changes in vegetation cover. Volcano flanks can become over-steep resulting in instability and mass wasting and this is now a recognised part of the growth of all active volcanoes. The failure of the flank of Mount St Helens in 1980 showed how rapidly volcanic flanks can deform. Water can increase or decrease the stability of a slope depending on the amount present, small amounts of water can strengthen soils because the surface tension of water increases soil cohesion. This allows the soil to resist erosion better than if it were dry, if too much water is present the water may act to increase the pore pressure, reducing friction, and accelerating the erosion process and resulting in different types of mass wasting. A good example of this is to think of a sand castle, water must be mixed with sand in order for the castle to keep its shape. If too much water is added the sand away, if not enough water is added the sand falls. Water also increases the mass of the soil, this is important because an increase in mass means that there will be an increase in velocity if mass wasting is triggered. Types of mass movement are distinguished based on how the soil, soil creep is a long term process. The combination of movements of soil or rock in different directions over time are directed by gravity gradually downslope. The steeper the slope, the faster the creep, the creep makes trees and shrubs curve to maintain their perpendicularity, and they can trigger landslides if they lose their root footing
3.
Rockfall
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A rockfall or rock-fall refers to quantities of rock falling freely from a cliff face. The term is used for collapse of rock from roof or walls of mine or quarry workings. Alternatively, a rockfall is the downward motion of a detached block or series of blocks with a small volume involving free falling, bouncing, rolling. The mode of failure differs from that of a rockslide, a tree may be blown by the wind, and this causes a pressure at the root level and this loosens rocks and can trigger a fall. The pieces of rock collect at the bottom creating a talus or scree, rocks falling from the cliff may dislodge other rocks and serve to create another mass wasting process, for example an avalanche. A cliff that has favorable geology to a rockfall may be said to be incompetent, one that is not favorable to a rockfall, which is better consolidated, may be said to be competent. Typically, rockfall events are mitigated in one of two ways, either by passive mitigation or active mitigation, the rockfall still takes place but an attempt is made to control the outcome. In contrast, active mitigation is carried out in the initiation zone, some examples of these measures are rock bolting, slope retention systems, shotcrete, etc. Other active measures might be by changing the geographic or climatic characteristics in the zone, e. g. altering slope geometry, dewatering the slope, revegetation. Design guides of passive measures have been proposed by Ritchie, Pierson et al, the effect of rockfalls on trees can be seen in several ways. The tree roots may rotate, via the energy of the rockfall. The tree may move via the application of translational energy, and lastly deformation may occur, either elastic or plastic. Dendrochronology can reveal a past impact, with missing tree rings, as the tree rings grow around and close over a gap, a macroscopic section can be used for dating of avalanche and rockfall events. Earthquake Kinetic energy Landslide Potential energy Protection forest Rockslide Slope stability SMR classification Q-slope
4.
Grade (slope)
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The grade of a physical feature, landform or constructed line refers to the tangent of the angle of that surface to the horizontal. It is a case of the slope, where zero indicates horizontality. A larger number indicates higher or steeper degree of tilt, often slope is calculated as a ratio of rise to run, or as a fraction in which run is the horizontal distance and rise is the vertical distance. The grades or slopes of existing physical features such as canyons and hillsides, stream and river banks, grades are typically specified for new linear constructions. The grade may refer to the slope or the perpendicular cross slope. There are several ways to express slope, as an angle of inclination to the horizontal, as a percentage, the formula for which is 100 rise run which could also be expressed as the tangent of the angle of inclination times 100. In the U. S. this percentage grade is the most commonly used unit for communicating slopes in transportation, surveying, construction, and civil engineering. As a per mille figure, the formula for which is 1000 rise run which could also be expressed as the tangent of the angle of inclination times 1000 and this is commonly used in Europe to denote the incline of a railway. As a ratio of one part rise to so many parts run, for example, a slope that has a rise of 5 feet for every 100 feet of run would have a slope ratio of 1 in 20. This is generally the method used to describe railway grades in Australia, any of these may be used. Grade is usually expressed as a percentage, but this is converted to the angle α from horizontal or the other expressions. Slope may still be expressed when the run is not known. This is not the way to specify slope, it follows the sine function rather than the tangent function. But in practice the way to calculate slope is to measure the distance along the slope and the vertical rise. When the angle of inclination is small, using the slope length rather than the horizontal displacement makes only an insignificant difference, Railway gradients are usually expressed in terms of the rise in relation to the distance along the track as a practical measure. In cases where the difference between sin and tan is significant, the tangent is used. In any case, the identity holds for all inclinations up to 90 degrees, tan α = sin α1 − sin 2 α In Europe. Grades are related using the equations with symbols from the figure at top
5.
Debris
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Depending on context, debris can refer to a number of different things. The first apparent use of the French word in English is in a 1701 description of the army of Prince Rupert upon its retreat from a battle with the army of Oliver Cromwell, in disaster scenarios, tornados leave behind large pieces of houses and mass destruction overall. This debris also flies around the tornado itself when it is in progress, the tornados winds capture debris it kicks up in its wind orbit, and spins it inside its vortex. The tornados wind radius is larger than the funnel itself, tsunamis and hurricanes also bring large amounts of debris, such as Hurricane Katrina in 2005 and Hurricane Sandy in 2012. Earthquakes rock cities to rubble debris, Geological debris sometimes moves in a stream called a debris flow. In mining, debris called attle usually consists of fragments which contain little or no ore. Marine debris is also called litter or flotsam and jetsam, objects that can constitute marine debris include used automobile tires, detergent bottles, medical wastes, discarded fishing line and nets, soda cans, and bilge waste solids. In addition to being unsightly, it can pose a threat to marine life, boats, swimmers, divers. For example, each year millions of seabirds, sea turtles, fish, as many as 30,000 northern fur seals per year get caught in abandoned fishing nets and either drown or suffocate. Whales mistake plastic bags for squid, and birds may mistake plastic pellets for fish eggs, at other times, animals accidentally eat the plastic while feeding on natural food. The largest concentration of debris is the Great Pacific Garbage Patch. Marine debris most commonly originates from land-based sources, various international agencies are currently working to reduce marine debris levels around the world. In meteorology, debris usually applies to the remains of human habitation and this debris is also commonly referred to as storm debris. Storm debris commonly consists of roofing material, downed tree limbs, downed signs, downed lines and poles. Storm debris can become a problem immediately after a storm, in that it often blocks access to individuals. This material frequently exists in large quantities that disposing of it becomes a serious issue for a community. In addition, storm debris is often hazardous by its nature, since, for example. Space usually refers to the remains of spacecraft that have fallen to Earth or are still orbiting Earth
6.
Submarine landslide
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Submarine landslides are marine landslides that transport sediment across the continental shelf and into the deep ocean. Submarine landslides take place in a variety of different settings including planes as low as 1°, recent advances have been made in understanding the nature and processes of submarine landslides through the use of sidescan sonar and other seafloor mapping technology. Submarine Landslides have different causes which relate to both the attributes of the landslide material and transient environmental factors affecting the submarine environment. The presence of weak geological layers is a factor which contributes to submarine landslides at all scales and this has been confirmed by seafloor imaging such as swath bathymetric mapping and 3D seismic reflection data. An example of a slide which was caused by weak geological layers is the Storegga slide, overpressure due to rapid deposition of sediment is closely related to weak geological layers. An example of landslides caused by due to rapid deposition occurred in 1969 on the Mississippi delta after Hurricane Camile struck the region. Earthquakes are a key factor which trigger most major submarine landslides, earthquakes provide significant environmental stresses and can promote elevated pore water pressure which leads to failure. Earthquakes triggered the Grand Banks landslide of 1929, where a 20 km3 submarine landslide was initiated after an earthquake, a number of studies have indicated that gas hydrates lie beneath many submarine slopes and can contribute to the triggering of a landslide. Gas hydrates are ice like substances consisting of water and natural gas, when the temperature rises or the pressure drops the gas hydrate becomes unstable allowing some of the hydrate to dissociate and discharge bubble phase natural gas. If pore water flow is impeded then this gas charging leads to excess water pressure. Gas hydrate dissociation is thought to have contributed to slides at water depths of 1000 to 1300 m off the east coast of the United States, groundwater seepage and elevated pore water pressure can cause submarine landslides. An example where glacial loading lead to submarine landsliding is the Nyk slide of northern Norway, slope failures due to volcanic island growth are among the largest on earth, involving volumes of several cubic kilometres. The failure occurs as large bodies of lava form above weak marine sediments which are prone to failure, failure is particularly common on edifices which are over 2500 m but rare on edifices which are less than 2500 m. Volcanic island submarine landslides occur in such as the Hawaiian Islands. Oversteepening is caused by scouring due to currents and can result in the triggering of submarine landslides. In some cases the relationship between the cause and the landslide can be quite clear while in other cases the relationships may not be so obvious. In most cases more than one factor may contribute towards the initiation of a landslide event and this is clearly seen on the Norwegian continental slope where the location of landslides such as Storegga and Traenadjupet is related to weak geological layers. Even when considering all the listed factors, in the end it was calculated that the landslide needed an earthquake for it to ultimately be initiated
7.
Coast
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A coastline or a seashore is the area where land meets the sea or ocean, or a line that forms the boundary between the land and the ocean or a lake. A precise line that can be called a coastline cannot be determined due to the Coastline paradox, the term coastal zone is a region where interaction of the sea and land processes occurs. Both the terms coast and coastal are often used to describe a location or region, for example, New Zealands West Coast. Edinburgh for example is a city on the coast of Scotland, a pelagic coast refers to a coast which fronts the open ocean, as opposed to a more sheltered coast in a gulf or bay. A shore, on the hand, can refer to parts of the land which adjoin any large body of water, including oceans. Similarly, the related term refers to the land alongside or sloping down to a river or to a body of water smaller than a lake. Bank is also used in parts of the world to refer to an artificial ridge of earth intended to retain the water of a river or pond. According to the UN atlas, 44% of people live within 150 kilometres of the sea, tides often determine the range over which sediment is deposited or eroded. Areas with high tidal ranges allow waves to reach farther up the shore, the tidal range is influenced by the size and shape of the coastline. Tides do not typically cause erosion by themselves, however, tidal bores can erode as the waves surge up river estuaries from the ocean. Waves erode coastline as they break on shore releasing their energy, the larger the wave the more energy it releases and the more sediment it moves. Coastlines with longer shores have more room for the waves to disperse their energy, while coasts with cliffs and short shore faces give little room for the wave energy to be dispersed. In these areas the wave energy breaking against the cliffs is higher, sediment deposited by waves comes from eroded cliff faces and is moved along the coastline by the waves. This forms an abrasion or cliffed coast, sediment deposited by rivers is the dominant influence on the amount of sediment located on a coastline. Today riverine deposition at the coast is often blocked by dams and other human regulatory devices, like the ocean which shapes them, coasts are a dynamic environment with constant change. The coast and its adjacent areas on and off shore are an important part of a local ecosystem, Salt marshes and beaches also support a diversity of plants, animals and insects crucial to the food chain. The high level of biodiversity creates a level of biological activity. More and more of the people live in coastal regions
8.
Gravity
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Gravity, or gravitation, is a natural phenomenon by which all things with mass are brought toward one another, including planets, stars and galaxies. Since energy and mass are equivalent, all forms of energy, including light, on Earth, gravity gives weight to physical objects and causes the ocean tides. Gravity has a range, although its effects become increasingly weaker on farther objects. The most extreme example of this curvature of spacetime is a hole, from which nothing can escape once past its event horizon. More gravity results in time dilation, where time lapses more slowly at a lower gravitational potential. Gravity is the weakest of the four fundamental interactions of nature, the gravitational attraction is approximately 1038 times weaker than the strong force,1036 times weaker than the electromagnetic force and 1029 times weaker than the weak force. As a consequence, gravity has an influence on the behavior of subatomic particles. On the other hand, gravity is the dominant interaction at the macroscopic scale, for this reason, in part, pursuit of a theory of everything, the merging of the general theory of relativity and quantum mechanics into quantum gravity, has become an area of research. While the modern European thinkers are credited with development of gravitational theory, some of the earliest descriptions came from early mathematician-astronomers, such as Aryabhata, who had identified the force of gravity to explain why objects do not fall out when the Earth rotates. Later, the works of Brahmagupta referred to the presence of force, described it as an attractive force. Modern work on gravitational theory began with the work of Galileo Galilei in the late 16th and this was a major departure from Aristotles belief that heavier objects have a higher gravitational acceleration. Galileo postulated air resistance as the reason that objects with less mass may fall slower in an atmosphere, galileos work set the stage for the formulation of Newtons theory of gravity. In 1687, English mathematician Sir Isaac Newton published Principia, which hypothesizes the inverse-square law of universal gravitation. Newtons theory enjoyed its greatest success when it was used to predict the existence of Neptune based on motions of Uranus that could not be accounted for by the actions of the other planets. Calculations by both John Couch Adams and Urbain Le Verrier predicted the position of the planet. A discrepancy in Mercurys orbit pointed out flaws in Newtons theory, the issue was resolved in 1915 by Albert Einsteins new theory of general relativity, which accounted for the small discrepancy in Mercurys orbit. The simplest way to test the equivalence principle is to drop two objects of different masses or compositions in a vacuum and see whether they hit the ground at the same time. Such experiments demonstrate that all objects fall at the rate when other forces are negligible
9.
Slope stability
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Slope stability is the potential of soil covered slopes to withstand and undergo movement. Stability is determined by the balance of stress and shear strength. A previously stable slope may be affected by preparatory factors. Triggering factors of a failure can be climatic events which can then make a slope actively unstable. Mass movements can be caused by increase in stress, such as loading, lateral pressure. Alternatively, shear strength may be decreased by weathering, changes in water pressure. Slope stability investigation, analysis, and design mitigation is typically completed by geologists, engineering geologists, as seen in Figure 1, earthen slopes can develop a cut-spherical weakness area. The probability of this happening can be calculated in advance using a simple 2-D circular analysis package, a primary difficulty with analysis is locating the most-probable slip plane for any given situation. Many landslides have only been analyzed after the fact, more recently slope stability radar technology has been employed, particularly in the mining industry, to gather real time data and assist in pro-actively determining the likelihood of slope failure. Real life failures in naturally deposited mixed soils are not necessarily circular, nevertheless, failures in pure clay can be quite close to circular. This is combined with increased soil weight due to the added groundwater, a shrinkage crack at the top of the slip may also fill with rain water, pushing the slip forward. At the other extreme, slab-shaped slips on hillsides can remove a layer of soil from the top of the underlying bedrock, again, this is usually initiated by heavy rain, sometimes combined with increased loading from new buildings or removal of support at the toe. Stability can thus be improved by installing drainage paths to reduce the destabilising forces. Once the slip has occurred, however, a weakness along the slip circle remains, Slope stability issues can be seen with almost any walk down a ravine in an urban setting. An example is shown in Figure 3, where a river is eroding the toe of a slope, and there is a swimming pool near the top of the slope. If the toe is eroded too far, or the swimming pool begins to leak, the forces driving a slope failure will exceed those resisting failure, if the forces available to resist movement are greater than the forces driving movement, the slope is considered stable. A factor of safety is calculated by dividing the forces resisting movement by the forces driving movement, discontinuity layout optimization Mass wasting Mohr-Coulomb theory Slope stability analysis Slope stability radar Coduto, Donald P. Geotechnical Engineering, Principles and Practices. ISBN 0-13-576380-0 Fredlund, D. G. H. Rahardjo, unsaturated Soil Mechanics in Engineering Practice
10.
Mudflow
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Mudflows contain a significant proportion of clay, which makes them more fluid than debris flows, thus, they are able to travel farther and across lower slope angles. Both types are generally mixtures of various kinds of materials of different sizes, mudflows are often called mudslides, a term applied indiscriminately by the mass media to a variety of mass wasting events. Mudflows often start as slides, becoming flows as water is entrained along the flow path, other types of mudflows include lahars and jökulhlaups. A statutory definition of flood-related mudslide appears in the United States National Flood Insurance Act of 1968, as amended, codified at 42 USC Sections 4001, heavy rainfall, snowmelt, or high levels of ground water flowing through cracked bedrock may trigger a movement of soil or sediments. Floods and debris flows may also occur when strong rains on hill or mountain slopes cause extensive erosion and/or what is known as channel scour, the 2006 Sidoarjo mud flow may have been caused by rogue drilling. Some broad mudflows are rather viscous and therefore slow, others very quickly. If large enough, they can devastate villages and countrysides and they are composed of at least 50% silt and clay-sized materials and up to 30% water. The point where a material begins to flow depends on its grain size. Fine grainy material or soil has a friction angle than a coarse sediment or a debris flow. On December 14,1999 in Vargas, Venezuela, a known as The Vargas tragedy significantly altered more than 60 kilometers of the coastline. Landslide is a general term than mudflow. It refers to the failure and subsequent movement downslope of any types of surface movement of soil, rock. The term incorporates earth slides, rock falls, debris flows and they do not have to be as fluid as a mudflow. Mudflows can be caused by heavy rains or a sudden thaw. They consist mainly of mud and water plus fragments of rock and other debris and they can move houses off their foundations or bury a place within minutes because of incredibly strong currents. When a mudflow occurs it is given four named areas, the scarp, in bigger mudflows the upper and lower shelves. The main scarp will be the area of incidence, the toe is the last affected area. The upper and lower shelves are located there is a large dip in the mudflows path
11.
Liquefaction
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Liquefaction occurs both as part of natural processes, and in man-made processes used in science and commerce. In geology, soil liquefaction refers to the process by which water-saturated, unconsolidated sediments are transformed into a substance that acts like a liquid, by undermining the foundations and base courses of infrastructure, liquefaction can cause serious damage. In physics and chemistry, the transitions from solid and gas to liquid may be referred to as liquefaction. The melting point is the temperature and pressure at which a solid becomes a liquid, in commercial and industrial situations, the process of condensing a gas to liquid is sometimes referred to as liquefaction of gases. Coal liquefaction is the production of fuels from coal using a variety of industrial processes. Liquefaction is also used in commercial and industrial settings to refer to mechanical dissolution of a solid by mixing, grinding or blending with a liquid. In kitchen or laboratory settings, solids may be chopped into smaller parts sometimes in combination with a liquid and this may be done with a blender, or liquidiser in British English. In biology, liquefaction often involves organic tissue turning into a more liquid-like state, for example, liquefactive necrosis in pathology, or liquefaction as a parameter in semen analysis
12.
Causes of landslides
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The causes of landslides are usually related to instabilities in slopes. It is usually possible to one or more landslide causes. The difference between two concepts is subtle but important. The landslide causes are the reasons that a landslide occurred in that location, Landslide causes are listed in the following table, and include geological factors, morphological factors, physical factors and factors associated with human activity. Causes may be considered to be factors that made the slope vulnerable to failure, the trigger is the single event that finally initiated the landslide. Thus, causes combine to make a slope vulnerable to failure, Landslides can have many causes but can only have one trigger as shown in the next figure. Usually, it is easy to determine the trigger after the landslide has occurred. Occasionally, even after detailed investigations, no trigger can be determined - this was the case in the large Mount Cook landslide in New Zealand 1991. It is unclear as to whether the lack of a trigger in such cases is the result of some unknown process acting within the landslide, or whether there was in fact a trigger, hence the trigger is the weathering process, but this is not detectable externally. In most cases we think of a trigger as a stimulus that induces an immediate or near-immediate response in the slope. The importance of rainfall as a trigger for landslides cannot be underestimated, a global survey of landslide occurrence in the 12 months to the end of September 2003 revealed that there were 210 damaging landslide events worldwide. Of these, over 90% were triggered by heavy rainfall, one rainfall event for example in Sri Lanka in May 2003 triggered hundreds of landslides, killing 266 people and rendering over 300,000 people temporarily homeless. In July 2003 an intense rain band associated with the annual Asian monsoon tracked across central Nepal, finally, landslides triggered by Hurricane Mitch in 1998 killed an estimated 18,000 people in Honduras, Nicaragua, Guatemala and El Salvador. So why does rainfall trigger so many landslides, principally this is because the rainfall drives an increase in pore water pressures within the soil. The Figure A illustrates the forces acting on a block on a slope. Movement is driven by stress, which is generated by the mass of the block acting under gravity down the slope. Resistance to movement is the result of the normal load, when the slope fills with water, the fluid pressure provides the block with buoyancy, reducing the resistance to movement. In addition, in some cases fluid pressures can act down the slope as a result of groundwater flow to provide a push to the landslide that further decreases the stability
13.
1985 Puerto Rico floods
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The 1985 Puerto Rico floods produced the deadliest single landslide on record in North America, killing at least 130 people in the Mameyes neighborhood of barrio Portugués Urbano in Ponce. The floods were the result of a tropical wave that emerged off the coast of Africa on September 29. The system moved into the Caribbean Sea on October 5 and produced rainfall across Puerto Rico. Two stations broke their 24-hour rainfall records set in 1899, the rains caused severe flooding in the southern half of Puerto Rico, which isolated towns, washed out roads, and caused rivers to exceed their banks. In addition to the landslide in Mameyes, the floods washed out a bridge in Santa Isabel that killed several people. The storm system caused about $125 million in damage and 180 deaths, the tropical wave later spawned Tropical Storm Isabel. The tropical wave caused the flooding moved off the west coast of Africa on September 29. Moving westward, the system entered the eastern Caribbean Sea on October 5, the waves associated convection, or thunderstorms, were amplified by an upper-level trough to its west. It was developing into a cyclone while it moved across Puerto Rico. When the systems rainbands reached the mountains of southern Puerto Rico, it produced torrential rainfall, the most intense rainfall occurred on October 6, and on that day two stations recorded 24-hour precipitation totals exceeding 23 in. These totals broke the 24-hour rainfall records set during the 1899 San Ciriaco hurricane, the town of Peñuelas reported very high rainfall totals in a short amount of time, including 2.75 in in one hour and 5.5 in in two hours. The highest rainfall total on Puerto Rico was 31.67 in in Toro Negro State Forest, rainfall spread across the island, and the southern half of Puerto Rico experienced totals of over 10 in. Rainfall totals over 7 in spread across the United States Virgin Islands, the tropical wave later spawned a low pressure area north of Hispaniola that became Tropical Storm Isabel on October 7, a day before the rains subsided in Puerto Rico. The storm ultimately struck Florida before dissipating on October 15, across Puerto Rico, heavy rains from the weather system caused river flooding and landslides. The rains most significantly affected the municipalities of Ponce, Juana Díaz, Santa Isabel, several stations reported 100 year flooding, just five months after similar floods affected the island. Several rivers exceeded their banks, and the Toa Vaca reservoir filled to its capacity for the time since it was constructed in 1972. Saturated soils caused mudslides throughout Puerto Rico, although only one resulted in loss of life, in the hillside community of Mameyes, within Ponce, there was a block slide at around 3,00 am local time on October 7. A large slab of sandstone detached from a hill, moving about 250,000 cu yd of material down the hill, the intense rainfall triggered the landslide, although pre-existing conditions such as a leaking water main and poor sewage flow likely contributed to the event
14.
Neighbourhood
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A neighbourhood, or neighborhood, is a geographically localised community within a larger city, town, suburb or rural area. Neighbourhoods are often social communities with considerable face-to-face interaction among members, the Old English word for neighbourhood was neahdæl. ”Most of the earliest cities around the world as excavated by archaeologists have evidence for the presence of social neighbourhoods. Historical documents shed light on life in numerous historical preindustrial or nonwestern cities. Neighbourhoods are typically generated by social interaction among people living near one another, in this sense they are local social units larger than households not directly under the control of city or state officials. In addition to social neighbourhoods, most ancient and historical cities also had administrative districts used by officials for taxation, record-keeping, administrative districts are typically larger than neighbourhoods and their boundaries may cut across neighbourhood divisions. In some cases, however, administrative districts coincided with neighbourhoods, for example, in the T’ang period Chinese capital city Chang’an, neighbourhoods were districts and there were state officials who carefully controlled life and activity at the neighbourhood level. Neighbourhoods in preindustrial cities often had some degree of social specialisation or differentiation, ethnic neighbourhoods were important in many past cities and remain common in cities today. One factor contributing to neighbourhood distinctiveness and social cohesion in past cities was the role of rural to urban migration and this was a continual process in preindustrial cities, and migrants tended to move in with relatives and acquaintances from their rural past. Neighbourhoods have been the site of delivery or service interventions in part as efforts to provide local, quality services. Alfred Kahn, as early as the mid-1970s, described the experience, theory and fads of neighbourhood service delivery over the decade, including discussion of income transfers. Neighbourhoods, as an aspect of community, also are the site of services for youth, including children with disabilities. While the term neighbourhood organisation is not as common in 2015, community and economic development activists have pressured for reinvestment in local communities and neighbourhoods. Community and Economic Development may be understood in different ways, and may involve faith-based groups, urban sociology even has a subset termed neighbourhood sociology which supports the study of local communities and the diversity of urban neighbourhoods. Neighbourhoods are also used in studies from postal codes and health disparities. Neighbourhoods are convenient, and always accessible, since you are already in your neighbourhood when you walk out your door, successful neighbourhood action frequently requires little specialised technical skill, and often little or no money. Action may call for an investment of time, but material costs are often low, with neighbourhood action, compared to activity on larger scales, results are more likely to be visible and quickly forthcoming. The streets are cleaner, the crosswalk is painted, the trees are planted, visible and swift results are indicators of success, and since success is reinforcing, the probability of subsequent neighbourhood action is increased. The social support that a neighbourhood may provide can serve as a buffer against various forms of adversity
15.
Puerto Rico
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Puerto Rico, officially the Commonwealth of Puerto Rico and briefly called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea. It is an archipelago that includes the island of Puerto Rico and a number of smaller ones such as Mona, Culebra. The capital and most populous city is San Juan and its official languages are Spanish and English, though Spanish predominates. The islands population is approximately 3.4 million, Puerto Ricos rich history, tropical climate, diverse natural scenery, renowned traditional cuisine, and attractive tax incentives make it a popular destination for travelers from around the world. Four centuries of Spanish colonial government transformed the ethnic, cultural and physical landscapes primarily with waves of African captives, and Canarian. In the Spanish imperial imagination, Puerto Rico played a secondary, in 1898, following the Spanish–American War, the United States appropriated Puerto Rico together with most former Spanish colonies under the terms of the Treaty of Paris. Puerto Ricans are natural-born citizens of the United States, however, Puerto Rico does not have a vote in the United States Congress, which governs the territory with full jurisdiction under the Puerto Rico Federal Relations Act of 1950. As a U. S. territory, American citizens residing on the island are disenfranchised at the level and may not vote for president. However, Congress approved a constitution, allowing U. S. citizens on the territory to elect a governor. A fifth referendum will be held in June 2017, with only Statehood, in early 2017, the Puerto Rican government-debt crisis posed serious problems for the government. The outstanding bond debt that had climbed to $70 billion or $12,000 per capita at a time with 12. 4% unemployment, the debt had been increasing during a decade long recession. Puerto Ricans often call the island Borinquen – a derivation of Borikén, its indigenous Taíno name, the terms boricua and borincano derive from Borikén and Borinquen respectively, and are commonly used to identify someone of Puerto Rican heritage. The island is also known in Spanish as la isla del encanto. Columbus named the island San Juan Bautista, in honor of Saint John the Baptist, eventually traders and other maritime visitors came to refer to the entire island as Puerto Rico, while San Juan became the name used for the main trading/shipping port and the capital city. The islands name was changed to Porto Rico by the United States after the Treaty of Paris of 1898, the anglicized name was used by the US government and private enterprises. The name was changed back to Puerto Rico by a joint resolution in Congress introduced by Félix Córdova Dávila in 1931, the ancient history of the archipelago known today as Puerto Rico is not well known. The scarce archaeological findings and early Spanish scholarly accounts from the colonial era constitute the basis of knowledge about them. The first comprehensive book on the history of Puerto Rico was written by Fray Íñigo Abbad y Lasierra in 1786, the first settlers were the Ortoiroid people, an Archaic Period culture of Amerindian hunters and fishermen who migrated from the South American mainland
16.
Groundwater
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Groundwater is the water present beneath Earths surface in soil pore spaces and in the fractures of rock formations. A unit of rock or a deposit is called an aquifer when it can yield a usable quantity of water. The depth at which pore spaces or fractures and voids in rock become completely saturated with water is called the water table. Groundwater is recharged from, and eventually flows to, the naturally, natural discharge often occurs at springs and seeps. Groundwater is also withdrawn for agricultural, municipal, and industrial use by constructing and operating extraction wells. The study of the distribution and movement of groundwater is hydrogeology, Groundwater is hypothesized to provide lubrication that can possibly influence the movement of faults. It is likely that much of Earths subsurface contains some water, Groundwater may not be confined only to Earth. The formation of some of the landforms observed on Mars may have influenced by groundwater. There is also evidence that water may also exist in the subsurface of Jupiters moon Europa. Groundwater is often cheaper, more convenient and less vulnerable to pollution than surface water, therefore, it is commonly used for public water supplies. For example, groundwater provides the largest source of water storage in the United States. Underground reservoirs contain far more water than the capacity of all surface reservoirs and lakes in the US, many municipal water supplies are derived solely from groundwater. Polluted groundwater is less visible, but more difficult to clean up, than pollution in rivers, Groundwater pollution most often results from improper disposal of wastes on land. An aquifer is a layer of substrate that contains and transmits groundwater. When water can flow directly between the surface and the zone of an aquifer, the aquifer is unconfined. The deeper parts of unconfined aquifers are more saturated since gravity causes water to flow downward. The upper level of this layer of an unconfined aquifer is called the water table or phreatic surface. Below the water table, where in general all pore spaces are saturated with water, is the phreatic zone, substrate with low porosity that permits limited transmission of groundwater is known as an aquitard
17.
Erosion
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In earth science, erosion is the action of surface processes that remove soil, rock, or dissolved material from one location on the Earths crust, then transport it away to another location. Eroded sediment or solutes may be transported just a few millimetres, the rates at which such processes act control how fast a surface is eroded. Feedbacks are also possible between rates of erosion and the amount of eroded material that is carried by, for example. Processes of erosion that produce sediment or solutes from a place contrast with those of deposition, while erosion is a natural process, human activities have increased by 10-40 times the rate at which erosion is occurring globally. At well-known agriculture sites such as the Appalachian Mountains, intensive farming practices have caused erosion up to 100x the speed of the rate of erosion in the region. Excessive erosion causes both on-site and off-site problems, on-site impacts include decreases in agricultural productivity and ecological collapse, both because of loss of the nutrient-rich upper soil layers. In some cases, the end result is desertification. Off-site effects include sedimentation of waterways and eutrophication of bodies, as well as sediment-related damage to roads. Intensive agriculture, deforestation, roads, anthropogenic climate change and urban sprawl are amongst the most significant human activities in regard to their effect on stimulating erosion, however, there are many prevention and remediation practices that can curtail or limit erosion of vulnerable soils. Rainfall, and the surface runoff which may result from rainfall, produces four types of soil erosion, splash erosion, sheet erosion, rill erosion. Splash erosion is generally seen as the first and least severe stage in the erosion process. In splash erosion, the impact of a falling raindrop creates a crater in the soil. The distance these soil particles travel can be as much as 0.6 m vertically and 1.5 m horizontally on level ground. If the soil is saturated, or if the rate is greater than the rate at which water can infiltrate into the soil. If the runoff has sufficient flow energy, it will transport loosened soil particles down the slope, sheet erosion is the transport of loosened soil particles by overland flow. Rill erosion refers to the development of small, ephemeral concentrated flow paths which function as both sediment source and sediment delivery systems for erosion on hillslopes, generally, where water erosion rates on disturbed upland areas are greatest, rills are active. Flow depths in rills are typically of the order of a few centimetres or less and this means that rills exhibit hydraulic physics very different from water flowing through the deeper, wider channels of streams and rivers. Gully erosion occurs when water accumulates and rapidly flows in narrow channels during or immediately after heavy rains or melting snow
18.
Wave
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In physics, a wave is an oscillation accompanied by a transfer of energy that travels through a medium. Frequency refers to the addition of time, wave motion transfers energy from one point to another, which displace particles of the transmission medium–that is, with little or no associated mass transport. Waves consist, instead, of oscillations or vibrations, around almost fixed locations, there are two main types of waves. Mechanical waves propagate through a medium, and the substance of this medium is deformed, restoring forces then reverse the deformation. For example, sound waves propagate via air molecules colliding with their neighbors, when the molecules collide, they also bounce away from each other. This keeps the molecules from continuing to travel in the direction of the wave, the second main type, electromagnetic waves, do not require a medium. Instead, they consist of periodic oscillations of electrical and magnetic fields generated by charged particles. These types vary in wavelength, and include radio waves, microwaves, infrared radiation, visible light, ultraviolet radiation, X-rays, waves are described by a wave equation which sets out how the disturbance proceeds over time. The mathematical form of this varies depending on the type of wave. Further, the behavior of particles in quantum mechanics are described by waves, in addition, gravitational waves also travel through space, which are a result of a vibration or movement in gravitational fields. While mechanical waves can be transverse and longitudinal, all electromagnetic waves are transverse in free space. A single, all-encompassing definition for the wave is not straightforward. A vibration can be defined as a back-and-forth motion around a reference value, however, a vibration is not necessarily a wave. An attempt to define the necessary and sufficient characteristics that qualify a phenomenon as a results in a blurred line. The term wave is often understood as referring to a transport of spatial disturbances that are generally not accompanied by a motion of the medium occupying this space as a whole. In a wave, the energy of a vibration is moving away from the source in the form of a disturbance within the surrounding medium and it may appear that the description of waves is closely related to their physical origin for each specific instance of a wave process. For example, acoustics is distinguished from optics in that sound waves are related to a rather than an electromagnetic wave transfer caused by vibration. Concepts such as mass, momentum, inertia, or elasticity and this difference in origin introduces certain wave characteristics particular to the properties of the medium involved
19.
Glacier
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A glacier is a persistent body of dense ice that is constantly moving under its own weight, it forms where the accumulation of snow exceeds its ablation over many years, often centuries. Glaciers slowly deform and flow due to stresses induced by their weight, creating crevasses, seracs and they also abrade rock and debris from their substrate to create landforms such as cirques and moraines. Glaciers form only on land and are distinct from the much thinner sea ice, between 35°N and 35°S, glaciers occur only in the Himalayas, Andes, Rocky Mountains, a few high mountains in East Africa, Mexico, New Guinea and on Zard Kuh in Iran. Glaciers cover about 10 percent of Earths land surface, continental glaciers cover nearly 13,000,000 km2 or about 98 percent of Antarcticas 13,200,000 km2, with an average thickness of 2,100 m. Greenland and Patagonia also have huge expanses of continental glaciers, Glacial ice is the largest reservoir of fresh water on Earth. Within high altitude and Antarctic environments, the temperature difference is often not sufficient to release meltwater. A large piece of compressed ice, or a glacier, appears blue as large quantities of water appear blue and this is because water molecules absorb other colors more efficiently than blue. The other reason for the color of glaciers is the lack of air bubbles. Air bubbles, which give a color to ice, are squeezed out by pressure increasing the density of the created ice. The word Glaceon is a loanword from French and goes back, via Franco-Provençal, to the Vulgar Latin glaciārium, derived from the Late Latin glacia, the processes and features caused by or related to glaciers are referred to as glacial. The process of establishment, growth and flow is called glaciation. The corresponding area of study is called glaciology, Glaciers are important components of the global cryosphere. Glaciers are categorized by their morphology, thermal characteristics, and behavior, cirque glaciers form on the crests and slopes of mountains. A glacier that fills a valley is called a valley glacier, a large body of glacial ice astride a mountain, mountain range, or volcano is termed an ice cap or ice field. Ice caps have a less than 50,000 km2 by definition. Glacial bodies larger than 50,000 km2 are called ice sheets or continental glaciers, several kilometers deep, they obscure the underlying topography. Only nunataks protrude from their surfaces, the only extant ice sheets are the two that cover most of Antarctica and Greenland. They contain vast quantities of water, enough that if both melted, global sea levels would rise by over 70 m
20.
Earthquake
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An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earths lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to people around. The seismicity or seismic activity of an area refers to the frequency, type, Earthquakes are measured using measurements from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe and these two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly imperceptible or weak and magnitude 7 and over potentially cause damage over larger areas. The largest earthquakes in historic times have been of magnitude slightly over 9, intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the damage to structures it causes. At the Earths surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground, when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity, in its most general sense, the word earthquake is used to describe any seismic event — whether natural or caused by humans — that generates seismic waves. Earthquakes are caused mostly by rupture of faults, but also by other events such as volcanic activity, landslides, mine blasts. An earthquakes point of rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter, tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior, once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the portion of the fault. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface and this process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of a total energy is radiated as seismic energy. Most of the energy is used to power the earthquake fracture growth or is converted into heat generated by friction
21.
Soil liquefaction
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In soil mechanics the term liquefied was first used by Allen Hazen in reference to the 1918 failure of the Calaveras Dam in California. The phenomenon is most often observed in saturated, loose, sandy soils and this is because a loose sand has a tendency to compress when a load is applied, dense sands by contrast tend to expand in volume or dilate. If the soil is saturated by water, a condition that exists when the soil is below the ground water table or sea level. In response to the soil compressing, this increases in pressure. These contacts between grains are the means by which the weight from buildings and overlying soil layers are transferred from the surface to layers of soil or rock at greater depths. This loss of soil structure causes it to all of its strength. Although the effects of liquefaction have been understood, it was more thoroughly brought to the attention of engineers after the 1964 Niigata earthquake and 1964 Alaska earthquake. It was also a factor in the destruction in San Franciscos Marina District during the 1989 Loma Prieta earthquake. A state of soil liquefaction occurs when the stress of soil is reduced to essentially zero. This may be initiated by either monotonic loading or cyclic loading, in both cases a soil in a saturated loose state, and one which may generate significant pore water pressure on a change in load are the most likely to liquefy. As pore water pressure rises a progressive loss of strength of the soil occurs as effective stress is reduced and it is more likely to occur in sandy or non-plastic silty soils, but may in rare cases occur in gravels and clays. A flow failure may initiate if the strength of the soil is reduced below the required to maintain equilibrium of a slope or footing of a building for instance. This can occur due to loading or cyclic loading, and can be sudden. A historical example is the Aberfan disaster, casagrande referred to this type of phenomena as flow liquefaction although a state of zero effective stress is not required for this to occur. The term cyclic refers to the occurrence of a state of soil when large shear strains have accumulated in response to cyclic loading. A typical reference strain for the occurrence of zero effective stress is 5% double amplitude shear strain. This is a soil test based definition, usually performed via cyclic triaxial, cyclic direct simple shear and these tests are performed to determine a soils resistance to liquefaction by observing the number of cycles of loading at a particular shear stress amplitude before it fails. Failure here is defined by the shear strain criteria
22.
Hope Slide
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The Hope Slide was the largest landslide ever recorded in Canada. It occurred in the hours of January 9,1965 in the Nicolum Valley in the Cascade Mountains near Hope, British Columbia. The volume of rock involved in the landslide has been estimated at 47 million cubic metres, two earthquakes were said to have been recorded in the general area of the slide. One quake occurred at 3,56 am and the second at 6,58 am, the slide that obliterated the mountains southwestern slope was discovered when members of the RCMP detachment at Hope BC were dispatched to what were first reported as a couple of small rock slides. Norman Stephanishin, the Arrow truck driver, had stopped behind the stuck convertible, Stephanishin, unable to turn his rig around on the narrow and icy road, tried to talk the four others into walking the five kilometres back to Sumallo Lodge. Unable to convince them, Stephanishin walked east to Sumallo Lodge to phone the Highways Dept, in a short distance, Stephanishin flagged down a Greyhound Lines bus traveling to Vancouver and persuaded the driver, David Hughes, to return with him to Sumallo Lodge. Hughes turned back and is credited with saving his passengers from a tragedy, rescue workers from Hope and Princeton found the body of Thomas Starchuck,39, of Aldergrove BC, driver of the hay truck. The body of Bernie Lloyd Beck,27, of Penticton BC, becks passengers, Dennis George Arlitt,23, of Penticton BC, and Mary Kalmakoff,21, of Shoreacres BC, were never recovered. Their bodies remain entombed under the rock, British Columbia Highways Minister Phil Gaglardi attended the scene and directed the construction of a temporary tote road over the southern portion of the slide. In twenty-one days a bumpy route had been established over the slide, the landslide was caused by the presence of pre-existing tectonic structures within the southwestern slope of Johnson Ridge. The lower parts of the scar are underlain by felsite sheets while the upper parts of the slide scar are underlain by highly jointed Paleozoic greenstone beds. Ongoing weathering and tectonic activity weakened the slide mass to the point where it had reached limiting equilibrium, Johnson Peak was the site of a previous smaller prehistoric rock-slide. The highway has since been rerouted around and over the base of the debris field 55 metres above the original ground level on the other side of valley. Most of the scar on the mountain face remains bare rock. It is quite visible from aircraft passing overhead. A view point on Highway 3 allows tourists to view the scar, a four kilometre stretch of the prior routing lays disused to the north of the new highway alignment. On August 13,1965, an aircraft piloted by S. W. K, on April 23,1966, a Royal Canadian Air Force Grumman CSR-110 Albatross serving with No.121 Composite Unit at RCAF Station Comox, BC crashed on the Hope Slide. It was the only RCAF Albatross loss, five of the six crew members died
23.
Volcano
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A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Earths volcanoes occur because its crust is broken into 17 major, therefore, on Earth, volcanoes are generally found where tectonic plates are diverging or converging. This type of volcanism falls under the umbrella of plate hypothesis volcanism, Volcanism away from plate boundaries has also been explained as mantle plumes. These so-called hotspots, for example Hawaii, are postulated to arise from upwelling diapirs with magma from the boundary,3,000 km deep in the Earth. Volcanoes are usually not created where two plates slide past one another. Erupting volcanoes can pose hazards, not only in the immediate vicinity of the eruption. Historically, so-called volcanic winters have caused catastrophic famines, the word volcano is derived from the name of Vulcano, a volcanic island in the Aeolian Islands of Italy whose name in turn comes from Vulcan, the god of fire in Roman mythology. The study of volcanoes is called volcanology, sometimes spelled vulcanology, at the mid-oceanic ridges, two tectonic plates diverge from one another as new oceanic crust is formed by the cooling and solidifying of hot molten rock. Most divergent plate boundaries are at the bottom of the oceans, therefore, most volcanic activity is submarine, black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed, for example, subduction zones are places where two plates, usually an oceanic plate and a continental plate, collide. In this case, the plate subducts, or submerges under the continental plate forming a deep ocean trench just offshore. In a process called flux melting, water released from the subducting plate lowers the temperature of the overlying mantle wedge. This magma tends to be very viscous due to its high content, so it often does not reach the surface. When it does reach the surface, a volcano is formed, typical examples of this kind of volcano are Mount Etna and the volcanoes in the Pacific Ring of Fire. Because tectonic plates move across them, each volcano becomes dormant and is eventually re-formed as the plate advances over the postulated plume and this theory is currently under criticism, however. The most common perception of a volcano is of a mountain, spewing lava and poisonous gases from a crater at its summit, however. The features of volcanoes are more complicated and their structure. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have features such as massive plateaus
24.
Deforestation
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Deforestation, clearance or clearing is the removal of a forest or stand of trees where the land is thereafter converted to a non-forest use. Examples of deforestation include conversion of forestland to farms, ranches, the most concentrated deforestation occurs in tropical rainforests. About 30% of Earths land surface is covered by forests, Deforestation occurs for multiple reasons, trees are cut down to be used for building or sold as fuel, while cleared land is used as pasture for livestock and plantation. The removal of trees without sufficient reforestation has resulted in damage to habitat, biodiversity loss and it has adverse impacts on biosequestration of atmospheric carbon dioxide. Deforestation has also used in war to deprive the enemy of cover for its forces. Modern examples of this were the use of Agent Orange by the British military in Malaya during the Malayan Emergency, as of 2005, net deforestation rates have ceased to increase in countries with a per capita GDP of at least US$4,600. Deforested regions typically incur significant adverse soil erosion and frequently degrade into wasteland, disregard of ascribed value, lax forest management and deficient environmental laws are some of the factors that allow deforestation to occur on a large scale. In many countries, deforestation, both naturally occurring and human-induced, is an ongoing issue, Deforestation causes extinction, changes to climatic conditions, desertification, and displacement of populations as observed by current conditions and in the past through the fossil record. More than half of all plant and land animal species in the live in tropical forests. Between 2000 and 2012,2.3 million square kilometres of forests around the world were cut down, as a result of deforestation, only 6.2 million square kilometres remain of the original 16 million square kilometres of forest that formerly covered the Earth. According to the United Nations Framework Convention on Climate Change secretariat, subsistence farming is responsible for 48% of deforestation, commercial agriculture is responsible for 32%, logging is responsible for 14%, and fuel wood removals make up 5%. Experts do not agree on whether industrial logging is an important contributor to global deforestation, some argue that poor people are more likely to clear forest because they have no alternatives, others that the poor lack the ability to pay for the materials and labour needed to clear forest. One study found that population increases due to fertility rates were a primary driver of tropical deforestation in only 8% of cases. Other causes of contemporary deforestation may include corruption of government institutions, the distribution of wealth and power, population growth and overpopulation. Globalization is often viewed as another cause of deforestation, though there are cases in which the impacts of globalization have promoted localized forest recovery. The degradation of forest ecosystems has also traced to economic incentives that make forest conversion appear more profitable than forest conservation. Some commentators have noted a shift in the drivers of deforestation over the past 30 years, Deforestation is ongoing and is shaping climate and geography. Deforestation is a contributor to global warming, and is cited as one of the major causes of the enhanced greenhouse effect
25.
Tillage
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Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shovelling, picking, mattock work, hoeing, examples of draft-animal-powered or mechanized work include ploughing, rototilling, rolling with cultipackers or other rollers, harrowing, and cultivating with cultivator shanks. There is a continuum, however. Any type of gardening or farming, but especially larger-scale commercial types, Tillage is often classified into two types, primary and secondary. There is no boundary between them so much as a loose distinction between tillage that is deeper and more thorough and tillage that is shallower and sometimes more selective of location. Harrowing and rototilling often combine primary and secondary tillage into one operation, Tillage can also mean the land that is tilled. The word cultivation has several senses that overlap substantially with those of tillage, in a general context, both can refer to agriculture. Within agriculture, both can refer to any kind of soil agitation, additionally, cultivation or cultivating may refer to an even narrower sense of shallow, selective secondary tillage of row crop fields that kills weeds while sparing the crop plants. Reduced tillage leaves between 15 and 30% residue cover on the soil or 500 to 1000 pounds per acre of small grain residue during the critical erosion period and this may involve the use of a chisel plow, field cultivators, or other implements. See the general comments below to see how they can affect the amount of residue, intensive tillage leaves less than 15% crop residue cover or less than 500 pounds per acre of small grain residue. Intensive tillage often involves multiple operations with such as a mold board, disk. Then a finisher with a harrow, rolling basket, and cutter can be used to prepare the seed bed. Conservation tillage leaves at least 30% of crop residue on the soil surface and this slows water movement, which reduces the amount of soil erosion. Conservation tillage also benefits farmers by reducing consumption and soil compaction. By reducing the number of times the farmer travels over the field, farmers realize significant savings in fuel, in most years since 1997, conservation tillage was used in US cropland more than intensive or reduced tillage. However, conservation tillage delays warming of the due to the reduction of dark earth exposure to the warmth of the spring sun. No-till - Never use a plow, disk, etc. ever again, strip-Till - Narrow strips are tilled where seeds will be planted, leaving the soil in between the rows untilled. Mulch-till Rotational Tillage - Tilling the soil every two years or less often, ridge-Till Zone tillage Zone tillage is a form of modified deep tillage in which only narrow strips are tilled, leaving soil in between the rows untilled
26.
Construction
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Construction is the process of constructing a building or infrastructure. Construction as an industry comprises six to nine percent of the domestic product of developed countries. Construction starts with planning, design, and financing, and continues until the project is built, large-scale construction requires collaboration across multiple disciplines. An architect normally manages the job, and a manager, design engineer. For the successful execution of a project, effective planning is essential, the largest construction projects are referred to as megaprojects. Construction is a term meaning the art and science to form objects, systems, or organizations. Construction is used as a verb, the act of building, and a noun, how a building was built, in general, there are three sectors of construction, buildings, infrastructure and industrial. Building construction is further divided into residential and non-residential. Infrastructure is often called heavy/highway, heavy civil or heavy engineering and it includes large public works, dams, bridges, highways, water/wastewater and utility distribution. Industrial includes refineries, process chemical, power generation, mills, there are other ways to break the industry into sectors or markets. Engineering News-Record is a magazine for the construction industry. Each year, ENR compiles and reports on data about the size of design and they publish a list of the largest companies in the United States and also a list the largest global firms. In 2014, ENR compiled the data in nine market segments and it was divided as transportation, petroleum, buildings, power, industrial, water, manufacturing, sewer/waste, telecom, hazardous waste plus a tenth category for other projects. In their reporting on the Top 400, they used data on transportation, sewer, hazardous waste, the Standard Industrial Classification and the newer North American Industry Classification System have a classification system for companies that perform or otherwise engage in construction. To recognize the differences of companies in this sector, it is divided into three subsectors, building construction, heavy and civil engineering construction, and specialty trade contractors, there are also categories for construction service firms and construction managers. Building construction is the process of adding structure to real property or construction of buildings, the majority of building construction jobs are small renovations, such as addition of a room, or renovation of a bathroom. Often, the owner of the property acts as laborer, paymaster, for this reason, those with experience in the field make detailed plans and maintain careful oversight during the project to ensure a positive outcome. Residential construction practices, technologies, and resources must conform to local building authority regulations, materials readily available in the area generally dictate the construction materials used
27.
Oscillation
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Oscillation is the repetitive variation, typically in time, of some measure about a central value or between two or more different states. The term vibration is used to describe mechanical oscillation. Familiar examples of oscillation include a swinging pendulum and alternating current power, the simplest mechanical oscillating system is a weight attached to a linear spring subject to only weight and tension. Such a system may be approximated on an air table or ice surface, the system is in an equilibrium state when the spring is static. If the system is displaced from the equilibrium, there is a net restoring force on the mass, tending to bring it back to equilibrium. However, in moving the back to the equilibrium position, it has acquired momentum which keeps it moving beyond that position. If a constant force such as gravity is added to the system, the time taken for an oscillation to occur is often referred to as the oscillatory period. All real-world oscillator systems are thermodynamically irreversible and this means there are dissipative processes such as friction or electrical resistance which continually convert some of the energy stored in the oscillator into heat in the environment. Thus, oscillations tend to decay with time there is some net source of energy into the system. The simplest description of this process can be illustrated by oscillation decay of the harmonic oscillator. In addition, a system may be subject to some external force. In this case the oscillation is said to be driven, some systems can be excited by energy transfer from the environment. This transfer typically occurs where systems are embedded in some fluid flow, at sufficiently large displacements, the stiffness of the wing dominates to provide the restoring force that enables an oscillation. The harmonic oscillator and the systems it models have a degree of freedom. More complicated systems have more degrees of freedom, for two masses and three springs. In such cases, the behavior of each variable influences that of the others and this leads to a coupling of the oscillations of the individual degrees of freedom. For example, two pendulum clocks mounted on a wall will tend to synchronise. This phenomenon was first observed by Christiaan Huygens in 1665, more special cases are the coupled oscillators where energy alternates between two forms of oscillation
28.
Machine (mechanical)
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Machines employ power to achieve desired forces and movement. A machine has a source and actuators that generate forces and movement. Modern machines often include computers and sensors that monitor performance and plan movement, the meaning of the word machine is traced by the Oxford English Dictionary to an independently functioning structure and by Merriam-Webster Dictionary to something that has been constructed. This includes human design into the meaning of machine, similarly Merriam-Webster Dictionary defines mechanical as relating to machinery or tools. Power flow through a machine provides a way to understand the performance of devices ranging from levers and gear trains to automobiles, notice that forces and motion combine to define power. More recently, Uicker et al. stated that a machine is a device for applying power or changing its direction, and McCarthy and Soh describe a machine as a system that generally consists of a power source and a mechanism for the controlled use of this power. The idea that a machine can be decomposed into simple movable elements led Archimedes to define the lever, pulley, by the time of the Renaissance this list increased to include the wheel and axle, wedge and inclined plane. The modern approach to characterizing machines focusses on the components that allow movement, wedge, Perhaps the first example of a device designed to manage power is the hand axe, also see biface and Olorgesailie. A hand axe is made by chipping stone, generally flint, to form a bifacial edge, a wedge is a simple machine that transforms lateral force and movement of the tool into a transverse splitting force and movement of the workpiece. The available power is limited by the effort of the using the tool, but because power is the product of force and movement. This amplification, or mechanical advantage is the ratio of the speed to output speed. For a wedge this is given by 1/tanα, where α is the tip angle, the faces of a wedge are modeled as straight lines to form a sliding or prismatic joint. Lever, The lever is another important and simple device for managing power and this is a body that pivots on a fulcrum. The fulcrum of a lever is modeled as a hinged or revolute joint, wheel, The wheel is clearly an important early machine, such as the chariot. A wheel uses the law of the lever to reduce the force needed to overcome friction when pulling a load. To see this notice that the associated with pulling a load on the ground is approximately the same as the friction in a simple bearing that supports the load on the axle of a wheel. However, the forms a lever that magnifies the pulling force so that it overcomes the frictional resistance in the bearing. Natural forces such as wind and water powered larger mechanical systems, waterwheels appeared around the world around 300 BC to use flowing water to generate rotary motion, which was applied to milling grain, and powering lumber, machining and textile operations
29.
Traffic
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Traffic on roads may consist of pedestrians, ridden or herded animals, vehicles, streetcars, buses and other conveyances, either singly or together, while using the public way for purposes of travel. Organized traffic generally has well-established priorities, lanes, right-of-way, Traffic is formally organized in many jurisdictions, with marked lanes, junctions, intersections, interchanges, traffic signals, or signs. Traffic is often classified by type, heavy vehicle, other vehicle. Different classes may share speed limits and easement, or may be segregated, some jurisdictions may have very detailed and complex rules of the road while others rely more on drivers common sense and willingness to cooperate. Organization typically produces a combination of travel safety and efficiency. Events which disrupt the flow and may cause traffic to degenerate into a disorganized mess include road construction, collisions, on particularly busy freeways, a minor disruption may persist in a phenomenon known as traffic waves. A complete breakdown of organization may result in traffic congestion and gridlock, simulations of organized traffic frequently involve queuing theory, stochastic processes and equations of mathematical physics applied to traffic flow. The word traffic originally meant trade and comes from the Old Italian verb trafficare, the origin of the Italian words is unclear. Rules of the road and driving etiquette are the practices and procedures that road users are required to follow. These rules usually apply to all users, though they are of special importance to motorists and cyclists. These rules govern interactions between vehicles and with pedestrians, the basic traffic rules are defined by an international treaty under the authority of the United Nations, the 1968 Vienna Convention on Road Traffic. Not all countries are signatory to the convention and, even among signatories, there are also unwritten local rules of the road, which are generally understood by local drivers. These rules should be distinguished from the procedures required to operate ones vehicle. Traffic going in opposite directions should be separated in such a way that they do not block each others way, the most basic rule is whether to use the left or right side of the road. In many countries, the rules of the road are codified, in the United Kingdom, the rules are set out in the Highway Code, which includes obligations but also advice on how to drive sensibly and safely. In the United States, traffic laws are regulated by the states and municipalities through their respective traffic codes, most of these are based at least in part on the Uniform Vehicle Code, but there are variations from state to state. However, states such as South Carolina have completely criminalized their traffic law, so, for example, vehicles often come into conflict with other vehicles and pedestrians because their intended courses of travel intersect, and thus interfere with each others routes. The general principle that establishes who has the right to go first is called right of way and it establishes who has the right to use the conflicting part of the road and who has to wait until the other does so
30.
Explosive material
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An explosive charge is a measured quantity of explosive material, which may be composed of a single ingredient or a combination of two or more. Materials that detonate are said to be high explosives and materials that deflagrate are said to be low explosives, Explosives may also be categorized by their sensitivity. Sensitive materials that can be initiated by a small amount of heat or pressure are primary explosives. A wide variety of chemicals can explode, a number are manufactured specifically for the purpose of being used as explosives. The remainder are too dangerous, sensitive, toxic, expensive, unstable, in contrast, some materials are merely combustible or flammable if they burn without exploding. The distinction, however, is not razor-sharp, though early thermal weapons, such as Greek fire, have existed since ancient times, the first widely used explosive in warfare and mining was black powder, invented in 9th century China. This material was sensitive to water, and it produced copious amounts of dark smoke, the first useful explosive stronger than black powder was nitroglycerin, developed in 1847. Since nitroglycerin is a liquid and highly unstable, it was replaced by nitrocellulose, TNT in 1863, smokeless powder, dynamite in 1867, World War I saw the adoption of TNT trinitrotoluene in artillery shells. World War II saw a use of new explosives. In turn, these have largely replaced by more powerful explosives such as C-4. However, C-4 and PETN react with metal and catch fire easily, yet unlike TNT, C-4 and PETN are waterproof, the largest commercial application of explosives is mining. In Materials Science and Engineering, explosives are used in cladding, a thin plate of some material is placed atop a thick layer of a different material, both layers typically of metal. Atop the thin layer is placed an explosive, at one end of the layer of explosive, the explosion is initiated. The two metallic layers are forced together at high speed and with great force, the explosion spreads from the initiation site throughout the explosive. Ideally, this produces a metallurgical bond between the two layers and it is possible that some fraction of the surface material from either layer eventually gets ejected when the end of material is reached. Hence, the mass of the now welded bilayer, may be less than the sum of the masses of the two initial layers, there are applications where a shock wave, and electrostatics, can result in high velocity projectiles. Thus, explosives are substances that contain an amount of energy stored in chemical bonds. Consequently, most commercial explosives are compounds containing -NO2, -ONO2 and -NHNO2 groups that
31.
Earthworks (engineering)
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Earthworks are engineering works created through the processing of parts of the earths surface involving quantities of soil or unformed rock. Other common earthworks are land grading to reconfigure the topography of a site, in military engineering, earthworks are, more specifically, types of fortifications constructed from soil. Although soil is not very strong, it is enough that huge quantities can be used. Examples of older earthwork fortifications include moats, sod walls, motte-and-bailey castles, modern examples include trenches and berms. Heavy construction equipment is used due to the amounts of material to be moved — up to millions of cubic metres. In the past, these calculations were done by using a slide rule. Earthworks cost is a function of hauled amount x hauled distance, the goal of mass haul planning is to determine these amounts and the goal of mass haul optimization is to minimize either or both. Now they can be performed with a computer and specialized software, including optimisation on haul cost and not haul distance
32.
Soil
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Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
33.
Root
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In vascular plants, the root is the organ of a plant that typically lies below the surface of the soil. Roots can also be aerial or aerating, that is growing up above the ground or especially above water, furthermore, a stem normally occurring below ground is not exceptional either. Therefore, the root is best defined as the non-leaf, non-nodes bearing parts of the plants body, however, important internal structural differences between stems and roots exist. The fossil record of roots – or rather, infilled voids where roots rotted after death – spans back to the late Silurian and their identification is difficult, because casts and molds of roots are so similar in appearance to animal burrows. They can be discriminated using a range of features, the first root that comes from a plant is called the radicle. In response to the concentration of nutrients, roots also synthesise cytokinin, Roots often function in storage of food and nutrients. The roots of most vascular plant species enter into symbiosis with fungi to form mycorrhizae. In its simplest form, the root architecture refers to the spatial configuration of a plant’s root system. This system can be complex and is dependent upon multiple factors such as the species of the plant itself, the composition of the soil. The configuration of root systems serves to support the plant, compete with other plants. Roots grow to specific conditions, which, if changed, can impede a plants growth. For example, a system that has developed in dry soil may not be as efficient in flooded soil, yet plants are able to adapt to other changes in the environment. Root architecture plays the important role of providing a supply of nutrients and water as well as anchorage. The main terms used to classify the architecture of a system are, Branch magnitude. Root angle, the angle of a lateral root’s base around the parent root’s circumference, the angle of a lateral root from its parent root. Link radius, the diameter of a root, all components of the root architecture are regulated through a complex interaction between genetic responses and responses due to environmental stimuli. These developmental stimuli are categorised as intrinsic, the genetic and nutritional influences, or extrinsic, the main hormones and respective pathways responsible for root architecture development include, Auxin – Auxin promotes root initiation, root emergence and primary root elongation. Cytokinins – Cytokinins regulate root apical meristem size and promote lateral root elongation, gibberellins – Together with ethylene they promote crown primordia growth and elongation
34.
Vegetation
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Vegetation is assemblages of plant species and the ground cover they provide. It is a term, without specific reference to particular taxa, life forms, structure, spatial extent. It is broader than the flora which refers to species composition. Perhaps the closest synonym is plant community, but vegetation can, primeval redwood forests, coastal mangrove stands, sphagnum bogs, desert soil crusts, roadside weed patches, wheat fields, cultivated gardens and lawns, all are encompassed by the term vegetation. The vegetation type is defined by characteristic dominant species, or an aspect of the assemblage. The contemporary use of vegetation approximates that of ecologist Frederic Clements term earth cover, Natural vegetation refers to plant life undisturbed by humans in its growth and which is controlled by the climatic conditions of that region. The distinction between vegetation and flora was first made by Jules Thurmann, prior to this, the two terms were used indiscriminately, and still are in some contexts. Augustin de Candolle also made a distinction, but he used the terms station and habitation. Later, the concept of vegetation would influence the usage of the term biome, other concepts similar to vegetation are physiognomy of vegetation and formation. Departing from Linnean taxonomy, Humboldt established a new science, dividing plant geography between taxonomists who studied plants as taxa and geographers who studied plants as vegetation. The physiognomic approach in the study of vegetation is common among biogeographers working on vegetation on a world scale, the concept vegetation type is more ambiguous. For some authors, it includes, besides physiognomy, floristic, furthermore, the phytosociological approach in the study of vegetation relies upon a fundamental unit, the plant association, which is defined upon flora. An influential, clear and simple scheme for types of vegetation was produced by Wagner & von Sydow. Like all the systems, plant communities are temporally and spatially dynamic. Dynamism in vegetation is defined primarily as changes in species composition and/or vegetation structure, temporally, a large number of processes or events can cause change, but for sake of simplicity they can be categorized roughly as either abrupt or gradual. Abrupt changes are referred to as disturbances, these include things like wildfires, high winds, landslides, floods, avalanches. Their causes are external to the community—they are natural processes occurring independently of the natural processes of the community. Such events can change vegetation structure and composition very quickly and for time periods
35.
Logging
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Logging is the cutting, skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. In forestry, the logging is sometimes used in a narrow sense concerning the logistics of moving wood from the stump to somewhere outside the forest. However, in usage, the term may be used to indicate a range of forestry or silviculture activities. Illegal logging refers to what in forestry might be called timber theft by the timber mafia and it can also refer to the harvesting, transportation, purchase, or sale of timber in violation of laws. Clearcut logging is not necessarily considered a type of logging but a harvesting or silviculture method, in the forest products industry logging companies may be referred to as logging contractors, with the smaller, non-union crews referred to as gyppo loggers. Cutting trees with the highest value and leaving those with lower value and it is sometimes called selective logging, and confused with selection cutting, the practice of managing stands by harvesting a proportion of trees. Logging usually refers to above-ground forestry logging, submerged forests exist on land that has been flooded by damming to create reservoirs. Such trees are logged using underwater logging or by the lowering of the reservoirs in question, ootsa Lake and Williston Lake in British Columbia, Canada are notable examples where timber recovery has been needed to remove inundated forests. Clearcutting, or clearfelling, is a method of harvesting that removes all the standing trees in a selected area. Silviculture objectives for clearcutting, and a focus on forestry distinguish it from deforestation, other methods include shelterwood cutting, group selective, single selective, seed-tree cutting, patch cut, and retention cutting. The above operations can be carried out by different methods, of which the three are considered industrial methods, Trees are felled and then delimbed and topped at the stump. The log is then transported to the landing, where it is bucked and loaded on a truck and this leaves the slash in the cut area, where it must be further treated if wild land fires are of concern. This ability is due to the advancement in the style felling head that can be used, the trees are then delimbed, topped, and bucked at the landing. This method requires that slash be treated at the landing, in areas with access to cogeneration facilities, the slash can be chipped and used for the production of electricity or heat. Full-tree harvesting also refers to utilization of the tree including branches. Cut-to-length logging is the process of felling, delimbing, bucking, harvesters fell the tree, delimb, and buck it, and place the resulting logs in bunks to be brought to the landing by a skidder or forwarder. This method is available for trees up to 900 mm in diameter. Harvesters are employed effectively in level to steep terrain
36.
Surte
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Surte is a locality situated in Ale Municipality, Västra Götaland County, Sweden. It had 5,798 inhabitants in 2010 and it is a located some 15 kilometers north of Gothenburg. Surte was the hometown of Alexander Samuelson, although he was not the designer, he was the man named on the 1915 design patent for the legendary contour Coca-Cola bottle. The international Grand Master of chess Gideon Ståhlberg, one of the worlds strongest players in the 1940s, was born and is buried in Surte, Surte is home to the bandy club Surte BK. They built one of the first indoor arenas in Sweden
37.
Landslide classification
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There have been known various classifications of landslides and other types of mass wasting. These systems are based on specific characteristics like shape of organs or nature of reproduction, for this reason, landslide classifications are based on different discriminating factors, sometimes very subjective. The second one is formed by those factors that have been utilised in some classifications and this is the most important criterion, even if uncertainties and difficulties can arise in the identification of movements, being the mechanisms of some landslides often particularly complex. The main movements are falls, slides and flows, but usually topples, lateral spreading, Rock, earth and debris are the terms generally used to distinguish the materials involved in the landslide process. For example, the distinction between earth and debris is made by comparing the percentage of coarse grain size fractions. If the weight of the particles with a greater than 2 mm is less than 20%. The classification of a landslide based on its activity is particularly relevant in the evaluation of future events, the recommendations of the WP/WLI define the concept of activity with reference to the spatial and temporal conditions, defining the state, the distribution and the style. This factor has an importance in the hazard evaluation. A velocity range is connected to the different type of landslides, Landslide dating is an interesting topic in the evaluation of hazard. The knowledge of the Landslide frequency is an element for any kind of probabilistic evaluation. Furthermore, the evaluation of the age of the permits to correlate the trigger to specific conditions. It is possible that phenomena could be occurred in past geological times, for example, in some Alpine areas, landslides of the Pleistocene age are connected with particular tectonic, geomorphological and climatic conditions. This represent a factor of the morphological evolution of a slope. Bedding attitude and the presence of discontinuities or faults control the slope morphogenesis, as the landslide is a geological volume with a hidden side, morphological characteristics are extremely important in the reconstruction of the technical model. This criterion describes, in a way, the location of landsides in the physiographic context of the area. As a consequence, specific morphological contexts are referred characterised by slope evolution processes, with these criteria, landslides can be identified with a system similar to that of the denomination of formations. Consequently, it is possible to describe a landslide using the name of a site, in particular, the name will be that of the locality where the landslide happened with a specific characteristic type. As a consequence, in the description of a landslide, it can be interesting to understand in what type of climate the event occurred, in the evaluation of landslide susceptibility, causes of the triggers is an important step
38.
Aquifer
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An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials from which groundwater can be extracted using a water well. The study of flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, if the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer. Aquifers may occur at various depths and those closer to the surface are not only more likely to be used for water supply and irrigation, but are also more likely to be topped up by the local rainfall. Many desert areas have limestone hills or mountains within them or close to them that can be exploited as groundwater resources, overexploitation can lead to the exceeding of the practical sustained yield, i. e. more water is taken out than can be replenished. The beach provides a model to help visualize an aquifer, if a hole is dug into the sand, very wet or saturated sand will be located at a shallow depth. This hole is a well, the wet sand represents an aquifer. In 2013 large freshwater aquifers were discovered under continental shelves off Australia, China, North America and they contain an estimated half a million cubic kilometers of “low salinity” water that could be economically processed into potable water. The reserves formed when ocean levels were lower and rainwater made its way into the ground in areas that were not submerged until the ice age ended 20,000 years ago. The volume is estimated to be 100x the amount of extracted from other aquifers since 1900. The above diagram indicates typical flow directions in a view of a simple confined or unconfined aquifer system. The system shows two aquifers with one aquitard between them, surrounded by the bedrock aquiclude, which is in contact with a gaining stream, the water table and unsaturated zone are also illustrated. An aquitard is a zone within the earth that restricts the flow of groundwater from one aquifer to another, an aquitard can sometimes, if completely impermeable, be called an aquiclude or aquifuge. Aquitards are composed of layers of clay or non-porous rock with low hydraulic conductivity. Groundwater can be found at every point in the Earths shallow subsurface to some degree. Saturated means the head of the water is greater than atmospheric pressure. The definition of the table is the surface where the pressure head is equal to atmospheric pressure. Unsaturated conditions occur above the table where the pressure head is negative
39.
Debris flow
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Debris flows descending steep channels commonly attain speeds that surpass 10 meters per second, although some large flows can reach speeds that are much greater. Debris flows with volumes ranging up to about 100,000 cubic meters occur frequently in mountainous regions worldwide, the largest prehistoric flows have had volumes exceeding 1 billion cubic meters. As a result of their high sediment concentrations and mobility, debris flows can be very destructive, notable debris-flow disasters of the twentieth century involved more than 20,000 fatalities in Armero, Colombia in 1985 and tens of thousands in Vargas State, Venezuela in 1999. Debris flows have volumetric sediment concentrations exceeding about 40 to 50%, by definition, “debris” includes sediment grains with diverse shapes and sizes, commonly ranging from microscopic clay particles to great boulders. Media reports often use the term mudflow to describe debris flows, on Earths land surface, mudflows are far less common than debris flows. However, underwater mudflows are prevalent on submarine continental margins, where they may spawn turbidity currents, Debris flows in forested regions can contain large quantities of woody debris such as logs and tree stumps. Sediment-rich water floods with solid concentrations ranging from about 10 to 40% behave somewhat differently from debris flows and are known as hyperconcentrated floods, normal stream flows contain even lower concentrations of sediment. Debris flows can be triggered by rainfall or snowmelt, by dam-break or glacial outburst floods. Debris flows can be more frequent following forest and brush fires, in Japan a large debris flow or landslide is called yamatsunami, literally mountain tsunami. Debris flows are accelerated downhill by gravity and tend to follow steep mountain channels that debouche onto alluvial fans or floodplains, the front, or head of a debris-flow surge often contains an abundance of coarse material such as boulders and logs that impart a great deal of friction. Trailing behind the high-friction flow head is a lower-friction, mostly liquefied flow body that contains a percentage of sand, silt. These fine sediments help retain high pore-fluid pressures that enhance debris-flow mobility, in some cases the flow body is followed by a more watery tail that transitions into a hyperconcentrated stream flow. Debris flows tend to move in a series of pulses, or discrete surges, wherein each pulse or surge has a head, body. Debris-flow deposits are readily recognizable in the field and they make up significant percentages of many alluvial fans and debris cones along steep mountain fronts. Lateral levees can confine the paths of ensuing debris flows, through dating of trees growing on such deposits, the approximate frequency of destructive debris flows can be estimated. This is important information for development in areas where debris flows are common. Ancient debris-flow deposits that are exposed only in outcrops are more difficult to recognize and this poor sorting of sediment grains distinguishes debris-flow deposits from most water-laid sediments. Other geological flows that can be described as debris flows are typically given more specific names, the word lahar is of Indonesian origin, but is now routinely used by geologists worldwide to describe volcanogenic debris flows
40.
Rock (geology)
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Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a rock, is a combination of the minerals quartz, feldspar. The Earths outer solid layer, the lithosphere, is made of rock, rock has been used by mankind throughout history. The minerals and metals found in rocks have been essential to human civilization, three major groups of rocks are defined, igneous, sedimentary, and metamorphic. The scientific study of rocks is called petrology, which is a component of geology. At a granular level, rocks are composed of grains of minerals, the aggregate minerals forming the rock are held together by chemical bonds. The types and abundance of minerals in a rock are determined by the manner in which the rock was formed, many rocks contain silica, a compound of silicon and oxygen that forms 74. 3% of the Earths crust. This material forms crystals with other compounds in the rock, the proportion of silica in rocks and minerals is a major factor in determining their name and properties. Rocks are geologically classified according to such as mineral and chemical composition, permeability, the texture of the constituent particles. These physical properties are the end result of the processes that formed the rocks, over the course of time, rocks can transform from one type into another, as described by the geological model called the rock cycle. These events produce three general classes of rock, igneous, sedimentary, and metamorphic, the three classes of rocks are subdivided into many groups. However, there are no hard and fast boundaries between allied rocks, hence the definitions adopted in establishing rock nomenclature merely correspond to more or less arbitrary selected points in a continuously graduated series. Igneous rock forms through the cooling and solidification of magma or lava and this magma can be derived from partial melts of pre-existing rocks in either a planets mantle or crust. Typically, the melting of rocks is caused by one or more of three processes, an increase in temperature, a decrease in pressure, or a change in composition, igneous rocks are divided into two main categories, plutonic rock and volcanic. Plutonic or intrusive rocks result when magma cools and crystallizes slowly within the Earths crust, a common example of this type is granite. Volcanic or extrusive rocks result from magma reaching the surface either as lava or fragmental ejecta, the chemical abundance and the rate of cooling of magma typically forms a sequence known as Bowens reaction series. Most major igneous rocks are found along this scale, about 64. 7% of the Earths crust by volume consists of igneous rocks, making it the most plentiful category. Of these, 66% are basalts and gabbros, 16% are granite, only 0. 6% are syenites and 0. 3% peridotites and dunites
41.
Tributary
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A tributary or affluent is a stream or river that flows into a larger stream or main stem river or a lake. A tributary does not flow directly into a sea or ocean, tributaries and the main stem river drain the surrounding drainage basin of its surface water and groundwater, leading the water out into an ocean. A confluence, where two or more bodies of water together, usually refers to the joining of tributaries. The opposite to a tributary is a distributary, a river or stream that branches off from, distributaries are most often found in river deltas. Right tributary and left tributary are terms stating the orientation of the relative to the flow of the main stem river. These terms are defined from the perspective of looking downstream, where tributaries have the same name as the river into which they feed, they are called forks. These are typically designated by compass direction, for example, the American River receives flow from its North, Middle, and South forks. The Chicago Rivers North Branch has the East, West, and Middle Fork, the South Branch has its South Fork, forks are sometimes designated as right or left. Here, the handedness is from the point of view of an observer facing upstream, for instance, Steer Creek has a left tributary which is called Right Fork Steer Creek. Tributaries are sometimes listed starting with those nearest to the source of the river, the Strahler Stream Order examines the arrangement of tributaries in a hierarchy of first, second, third, and higher orders, with the first-order tributary being typically the least in size. For example, a second-order tributary would be the result of two or more first-order tributaries combining to form the second-order tributary, another method is to list tributaries from mouth to source, in the form of a tree structure, stored as a tree data structure
42.
Flood
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A flood is an overflow of water that submerges land which is usually dry. The European Union Floods Directive defines a flood as a covering by water of land not normally covered by water, in the sense of flowing water, the word may also be applied to the inflow of the tide. Floods can also occur in rivers when the flow exceeds the capacity of the river channel. Floods often cause damage to homes and businesses if they are in the flood plains of rivers. Some floods develop slowly, while others such as floods, can develop in just a few minutes. Additionally, floods can be local, impacting a neighborhood or community, or very large, the word flood comes from the Old English flod, a word common to Germanic languages. Deluge myths are stories of a great flood sent by a deity or deities to destroy civilization as an act of divine retribution. Floods can happen on flat or low-lying areas when water is supplied by rainfall or snowmelt more rapidly than it can infiltrate or run off. The excess accumulates in place, sometimes to hazardous depths, surface soil can become saturated, which effectively stops infiltration, where the water table is shallow, such as a floodplain, or from intense rain from one or a series of storms. Infiltration also is slow to negligible through frozen ground, rock, concrete, paving, areal flooding begins in flat areas like floodplains and in local depressions not connected to a stream channel, because the velocity of overland flow depends on the surface slope. Endorheic basins may experience flooding during periods when precipitation exceeds evaporation. Floods occur in all types of river and stream channels, from the smallest ephemeral streams in humid zones to normally-dry channels in arid climates to the worlds largest rivers. When overland flow occurs on tilled fields, it can result in a flood where sediments are picked up by run off. Localized flooding may be caused or exacerbated by drainage obstructions such as landslides, ice, debris, slow-rising floods most commonly occur in large rivers with large catchment areas. The increase in flow may be the result of sustained rainfall, rapid snow melt, monsoons, the cause may be localized convective precipitation or sudden release from an upstream impoundment created behind a dam, landslide, or glacier. In one instance, a flood killed eight people enjoying the water on a Sunday afternoon at a popular waterfall in a narrow canyon. Without any observed rainfall, the rate increased from about 50 to 1,500 cubic feet per second in just one minute. Two larger floods occurred at the site within a week
43.
Flash flood
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A flash flood is a rapid flooding of geomorphic low-lying areas, washes, rivers, dry lakes and basins. It may be caused by heavy rain associated with a thunderstorm, hurricane, tropical storm. Flash floods may occur after the collapse of an ice or debris dam, or a human structure such as a man-made dam. Flash floods are distinguished from regular floods by a timescale of less than six hours, the water that is temporarily available is often used by foliage with rapid germination and short growth cycles, and by specially adapted animal life. Flash floods can occur under several types of conditions, Flash flooding occurs when it rains rapidly on saturated soil or dry soil that has poor absorption ability. The runoff collects in gullies and streams and, as they join to form larger volumes, often forms a fast flowing front of water, in areas on or near volcanoes, flash floods have also occurred after eruptions, when glaciers have been melted by the intense heat. Flash floods are known to occur in the highest mountain ranges of the United States and are common in the arid plains of the Southwestern United States. Flash flooding can also be caused by extensive rainfall released by hurricanes and other tropical storms, human activities can also cause flash floods to occur. When dams fail, a quantity of water can be released. Many people tend to underestimate the dangers of flash floods, what makes flash floods most dangerous is their sudden nature and fast-moving water. A vehicle provides little to no protection against being swept away, it may make people overconfident, more than half of the fatalities attributed to flash floods are people swept away in vehicles when trying to cross flooded intersections. As little as 2 feet of water is enough to carry away most SUV-sized vehicles. The U. S. National Weather Service reported in 2005 that, using a national 30-year average, more people die yearly in floods,127 on average, than by lightning, tornadoes, in deserts, flash floods can be particularly deadly for several reasons. First, storms in arid regions are infrequent, but they can deliver an enormous amount of water in a short time. Second, these rains often fall on poorly absorbent and often clay-like soil, in fact, in some areas, desert roads frequently cross dry river and creek beds without bridges. From the drivers perspective, there may be clear weather, when a river unexpectedly forms ahead of or around the vehicle in a matter of seconds. Finally, the lack of rain to clear water channels may cause flash floods in deserts to be headed by large amounts of debris, such as rocks, branches. 1889, Johnstown Flood, Pennsylvania, U. S. more than 2,200 people dead 1903, Heppner Flood of 1903, Oregon, United States,247 dead, 25% of the city 1938, Los Angeles Flood of 1938, California, U. S. S
44.
Alpine climate
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Alpine climate is the average weather for the regions above the tree line. This climate is referred to as a mountain climate or highland climate. There are multiple definitions of alpine climate, one simple definition is the climate which causes trees to fail to grow due to cold. According to the Holdridge life zone system, alpine climate occurs when the mean biotemperature of a location is between 1.5 and 3 °C, which prevents tree growth. Biotemperature is defined as the temperature, except all temperatures below 0 °C are treated as 0 °C, in the Köppen climate classification, the alpine climate is part of Group E, along with the polar climate, where no month has a mean temperature higher than 10 °C. The temperature profile of the atmosphere is a result of an interaction between radiation and convection, sunlight in the visible spectrum hits the ground and heats it. The ground then heats the air at the surface, however, when air is hot, it tends to expand, which lowers its density. Thus, hot air tends to rise and transfer heat upward and this is the process of convection. Convection comes to equilibrium when a parcel at air at a given altitude has the density as its surroundings. Air is a conductor of heat, so a parcel of air will rise. This is known as a process, which has a characteristic pressure-temperature curve. As the pressure gets lower, the temperature decreases, the rate of decrease of temperature with elevation is known as the adiabatic lapse rate, which is approximately 9.8 °C per kilometre of altitude. Note that the presence of water in the atmosphere complicates the process of convection, water vapor contains latent heat of vaporization. As air rises and cools, it becomes saturated and cannot hold its quantity of water vapor. The water vapor condenses, and releases heat, which changes the rate from the dry adiabatic lapse rate to the moist adiabatic lapse rate. The actual lapse rate, called the lapse rate, is not constant. Therefore, moving up 100 metres on a mountain is roughly equivalent to moving 80 kilometres towards the pole and this relationship is only approximate, however, since local factors, such as proximity to oceans, can drastically modify the climate. As the altitude increases, the form of precipitation becomes snow
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