1.
Mount Pinatubo
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Its eruptive history was unknown to most before the pre-eruption volcanic activities of 1991, just before June. Pinatubo was heavily eroded, inconspicuous and obscured from view and it was covered with dense forests which supported a population of several thousand indigenous Aetas. The volcanos Ultra Plinian eruption on June 15,1991 produced the second-largest terrestrial eruption of the 20th century after the 1912 eruption of Novarupta in the Alaska Peninsula. Complicating the eruption was the arrival of Typhoon Yunya, bringing a lethal mix of ash and rain to towns. Predictions at the onset of the eruption led to the evacuation of tens of thousands of people from the surrounding areas. Surrounding areas were damaged by pyroclastic surges, ash falls. This caused extensive destruction to infrastructure and changed river systems for years after the eruption, the effects of the eruption were felt worldwide. It ejected roughly 10,000,000,000 tonnes or 10 km3 of magma and it injected more particulate into the stratosphere than any eruption since Krakatoa in 1883. Over the following months, the aerosols formed a layer of sulfuric acid haze. Global temperatures dropped by about 0.5 °C in the years 1991–93, the volcano is 87 km northwest of Manila, the capital of the Philippines. Near Mount Pinatubo, the United States maintained two military bases in the region. The U. S. Naval Base Subic Bay was 37 km south of Pinatubo, the volcano is near to about 6 million people. It is part of a chain of volcanoes lie along the western side of the edge of the island of Luzon called the Zambales Mountains. Pinatubo belongs to the Cabusilan sub-range of the Zambales Mountains, which consists of Mt. Cuadrado, Mt. Negron, Mt. Mataba and they are subduction volcanoes, formed by the Eurasian Plate sliding under the Philippine Mobile Belt along the Manila Trench to the west. Mount Pinatubo and the volcanoes on this volcanic belt arise due to magmatic occlusion from this subduction plate boundary. Pinatubo is flanked on the west by the Zambales Ophiolite Complex, the Tarlac Formation north, east and southeast of Pinatubo consists of marine, nonmarine and volcanoclastic sediments formed in the late Miocene and Pliocene. He recognized two life histories of the mountain, which he classified as ancestral and modern Pinatubo, activity of Ancestral Pinatubo seems to have begun about 1.1 million years ago and probably ended tens of thousands of years or more before the birth of Modern Pinatubo. Much of the land around the present volcano consists of remnants of ancestral Pinatubo
2.
Philippines
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The Philippines, officially the Republic of the Philippines, is a sovereign island country in Southeast Asia situated in the western Pacific Ocean. It consists of about 7,641 islands that are categorized broadly under three main geographical divisions from north to south, Luzon, Visayas, and Mindanao, the capital city of the Philippines is Manila and the most populous city is Quezon City, both part of Metro Manila. The Philippines has an area of 300,000 square kilometers, and it is the eighth-most populated country in Asia and the 12th most populated country in the world. As of 2013, approximately 10 million additional Filipinos lived overseas, multiple ethnicities and cultures are found throughout the islands. In prehistoric times, Negritos were some of the archipelagos earliest inhabitants and they were followed by successive waves of Austronesian peoples. Exchanges with Chinese, Malay, Indian, and Islamic nations occurred, then, various competing maritime states were established under the rule of Datus, Rajahs, Sultans or Lakans. The arrival of Ferdinand Magellan in Homonhon, Eastern Samar in 1521 marked the beginning of Hispanic colonization, in 1543, Spanish explorer Ruy López de Villalobos named the archipelago Las Islas Filipinas in honor of Philip II of Spain. With the arrival of Miguel López de Legazpi from Mexico City, in 1565, the Philippines became part of the Spanish Empire for more than 300 years. This resulted in Roman Catholicism becoming the dominant religion, during this time, Manila became the western hub of the trans-Pacific trade connecting Asia with Acapulco in the Americas using Manila galleons. Aside from the period of Japanese occupation, the United States retained sovereignty over the islands until after World War II, since then, the Philippines has often had a tumultuous experience with democracy, which included the overthrow of a dictatorship by a non-violent revolution. It is a member of the United Nations, World Trade Organization, Association of Southeast Asian Nations, the Asia-Pacific Economic Cooperation forum. It also hosts the headquarters of the Asian Development Bank, the Philippines was named in honor of King Philip II of Spain. Spanish explorer Ruy López de Villalobos, during his expedition in 1542, named the islands of Leyte, eventually the name Las Islas Filipinas would be used to cover all the islands of the archipelago. Before that became commonplace, other such as Islas del Poniente. The official name of the Philippines has changed several times in the course of its history, during the Philippine Revolution, the Malolos Congress proclaimed the establishment of the República Filipina or the Philippine Republic. From the 1898 Treaty of Paris, the name Philippines began to appear, since the end of World War II, the official name of the country has been the Republic of the Philippines. The metatarsal of the Callao Man, reliably dated by uranium-series dating to 67,000 years ago is the oldest human remnant found in the archipelago to date and this distinction previously belonged to the Tabon Man of Palawan, carbon-dated to around 26,500 years ago. Negritos were also among the archipelagos earliest inhabitants, but their first settlement in the Philippines has not been reliably dated, there are several opposing theories regarding the origins of ancient Filipinos
3.
Volcanic ash
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Volcanic ash consists of fragments of pulverized rock, minerals and volcanic glass, created during volcanic eruptions and measuring less than 2 mm in diameter. The term volcanic ash is often loosely used to refer to all explosive eruption products. Volcanic ash is formed during volcanic eruptions when dissolved gases in magma expand. The force of the escaping gas shatters the magma and propels it into the atmosphere where it solidifies into fragments of volcanic rock and glass. Ash is also produced when magma comes into contact with water during phreatomagmatic eruptions, once in the air, ash is transported by wind up to thousands of kilometers away. Volcanic ash is formed during volcanic eruptions, phreatomagmatic eruptions. Explosive eruptions occur when magma decompresses as it rises, allowing dissolved volatiles to exsolve into gas bubbles, as more bubbles nucleate a foam is produced, which decreases the density of the magma, accelerating it up the conduit. Fragmentation occurs when bubbles occupy ~70-80 vol% of the erupting mixture, when fragmentation occurs, violently expanding bubbles tear the magma apart into fragments which are ejected into the atmosphere where they solidify into ash particles. Fragmentation is an efficient process of ash formation and is capable of generating very fine ash even without the addition of water. Volcanic ash is produced during phreatomagmatic eruptions. During these eruptions fragmentation occurs when magma comes into contact with bodies of water groundwater, as the magma, which is significantly hotter than the boiling point of water, comes into contact with water an insulating vapor film forms. Eventually this vapor film will collapse leading to direct coupling of the cold water and this increases the heat transfer which leads to the rapid expansion of water and fragmentation of the magma into small particles which are subsequently ejected from the volcanic vent. Fragmentation causes an increase in area between magma and water creating a feedback mechanism, leading to further fragmentation and production of fine ash particles. Pyroclastic density currents can also produce ash particles and these are typically produced by lava dome collapse or collapse of the eruption column. Within pyroclastic density currents particle abrasion occurs as particles interact with each resulting in a reduction in grain size. In addition, ash can be produced during secondary fragmentation of pumice fragments and these processes produce large quantities of very fine grained ash which is removed from pyroclastic density currents in co-ignimbrite ash plumes. Physical and chemical characteristics of volcanic ash are primarily controlled by the style of volcanic eruption, another parameter controlling the amount of ash produced is the duration of the eruption, the longer the eruption is sustained, the more ash will be produced. The types of minerals present in volcanic ash are dependent on the chemistry of the magma from which it erupted, low energy eruptions of basalt produce a characteristically dark coloured ash containing ~45 - 55% silica that is generally rich in iron and magnesium
4.
Tephra
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Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts, once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff. Tephra mixed in with precipitation can also be acidic and cause acid rain, the use of tephra layers, which bear their own unique chemistry and character, as temporal marker horizons in archaeological and geological sites is known as tephrochronology. The word tephra and pyroclast both derive from Greek, τέφρα tephra means ash, while the word pyroclast is derived from the Greek πῦρ, meaning fire, media related to Tephra at Wikimedia Commons How Volcanoes Work Volcanic Materials Identification
5.
Types of volcanic eruptions
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Several types of volcanic eruptions—during which lava, tephra, and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed, some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series. There are three different types of eruptions, the most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. Phreatomagmatic eruptions are another type of eruption, driven by the compression of gas within magma. Within these wide-defining eruptive types are several subtypes, the weakest are Hawaiian and submarine, then Strombolian, followed by Vulcanian and Surtseyan. The stronger eruptive types are Pelean eruptions, followed by Plinian eruptions, subglacial and phreatic eruptions are defined by their eruptive mechanism, and vary in strength. An important measure of strength is Volcanic Explosivity Index, an order of magnitude scale ranging from 0 to 8 that often correlates to eruptive types. Explosive eruptions are characterized by gas-driven explosions that propels magma and tephra, effusive eruptions, meanwhile, are characterized by the outpouring of lava without significant explosive eruption. Volcanic eruptions vary widely in strength, on the one extreme there are effusive Hawaiian eruptions, which are characterized by lava fountains and fluid lava flows, which are typically not very dangerous. On the other extreme, Plinian eruptions are large, violent, volcanoes are not bound to one eruptive style, and frequently display many different types, both passive and explosive, even the span of a single eruptive cycle. Volcanoes do not always erupt vertically from a crater near their peak. Some volcanoes exhibit lateral and fissure eruptions, notably, many Hawaiian eruptions start from rift zones, and some of the strongest Surtseyan eruptions develop along fracture zones. Scientists believed that pulses of magma mixed together in the chamber before climbing upward—a process estimated to several thousands of years. But Columbia University volcanologists found that the eruption of Costa Rica’s Irazú Volcano in 1963 was likely triggered by magma that took a route from the mantle over just a few months. The volcanic explosivity index is a scale, from 0 to 8 and it is used by the Smithsonian Institutions Global Volcanism Program in assessing the impact of historic and prehistoric lava flows. It operates in a way similar to the Richter scale for earthquakes, the vast majority of volcanic eruptions are of VEIs between 0 and 2. Volcanic eruptions by VEI index Magmatic eruptions produce juvenile clasts during explosive decompression from gas release, Hawaiian eruptions are a type of volcanic eruption, named after the Hawaiian volcanoes with which this eruptive type is hallmark. Hawaiian eruptions are the calmest types of events, characterized by the effusive eruption of very fluid basalt-type lavas with low gaseous content
6.
Climate change
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Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time. Climate change may refer to a change in weather conditions. Climate change is caused by such as biotic processes, variations in solar radiation received by Earth, plate tectonics. Certain human activities have also identified as significant causes of recent climate change. Scientists actively work to understand past and future climate by using observations, more recent data are provided by the instrumental record. The most general definition of change is a change in the statistical properties of the climate system when considered over long periods of time. Accordingly, fluctuations over periods shorter than a few decades, such as El Niño, the term climate change is often used to refer specifically to anthropogenic climate change. Anthropogenic climate change is caused by activity, as opposed to changes in climate that may have resulted as part of Earths natural processes. In this sense, especially in the context of environmental policy, within scientific journals, global warming refers to surface temperature increases while climate change includes global warming and everything else that increasing greenhouse gas levels affect. A related term is climatic change, in 1966, the World Meteorological Organization proposed the term climatic change to encompass all forms of climatic variability on time-scales longer than 10 years, regardless of cause. Change was a given and climatic was used as an adjective to describe this kind of change, when it was realized that human activities had a potential to drastically alter the climate, the term climate change replaced climatic change as the dominant term to reflect an anthropogenic cause. Climate change was incorporated in the title of the Intergovernmental Panel on Climate Change, Climate change, used as a noun, became an issue rather than the technical description of changing weather. On the broadest scale, the rate at which energy is received from the Sun and this energy is distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions. Factors that can shape climate are called climate forcings or forcing mechanisms, there are a variety of climate change feedbacks that can either amplify or diminish the initial forcing. Some parts of the system, such as the oceans and ice caps, respond more slowly in reaction to climate forcings. There are also key factors which when exceeded can produce rapid change. Forcing mechanisms can be internal or external. Internal forcing mechanisms are natural processes within the system itself
7.
Mount Redoubt
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Redoubt Volcano, or Mount Redoubt, is an active stratovolcano in the largely volcanic Aleutian Range of the U. S. state of Alaska. At 10,197 feet, in just over 5 miles Mount Redoubt attains 9,150 feet of prominence over its surrounding terrain and it is the highest summit in the Aleutian Range. Active for millennia, Mount Redoubt has erupted four times since it was first observed, in 1902,1966,1989 and 2009, the eruption in 1989 spewed volcanic ash to a height of 45,000 ft. It caught KLM Flight 867, a Boeing 747 aircraft, in its plume, after the plane descended 13,000 feet, the pilots restarted the engines and landed the plane safely at Anchorage. The ash blanketed an area of about 7,700 sq mi, as of August 2015, the Alaska Volcano Observatory has rated Redoubt as Aviation Alert Level Green and Volcano Alert Level Normal. The official name of the mountain is Redoubt Volcano, a translation of the Russian name Sopka Redutskaya, referring to, as does the word redoubt, a fortified place. A local name, Ujakushatsch, also means fortified place, the Board on Geographic Names decided on the name Redoubt Volcano in 1891. The Alaska Volcano Observatory also uses simply Redoubt, it lists the alternate names in addition to the following, Goryalaya, Redoute Mtn. and Redutskaya. The volcano is about 3.7 miles in diameter at its base with a volume of 7.2 to 8.4 cu mi. The sides of the cone are relatively steep. The current main vent is on the side of the crater by the head of the Drift glacier. Also present on the mountain are Holocene lahar deposits that extend as far as the Cook Inlet and this mountain has produced andesite, basalt and dacite, with relatively silicic andesite dominant in recent eruptions. But this besides being too small for one of those clouds, however, several sources call this a discredited eruption. There are several other of these activities that are not called eruptions, in 1819, smoke was observed at the mountain. However, this is not recorded as an eruption as the information was insufficient to identify it as such. Similarly, in 2003, a cloud of snow was mistaken by an employee of the ConocoPhillips Building in Anchorage for an ash plume. Possible steam-vapor let off was observed in 1933 at the mountain, there was apparently an eruption described as to the eastward, Redoubt Volcano,11,060 feet high, is constantly smoking, with periods of exaggerated activity. Fire has been seen issuing from its summit far out at sea, a great eruption took place in 1881, when a party of native hunters half-way up its slopes were overwhelmed by a lava-flow and only two escaped
8.
Gas
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Gas is one of the four fundamental states of matter. A pure gas may be made up of atoms, elemental molecules made from one type of atom. A gas mixture would contain a variety of pure gases much like the air, what distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colorless gas invisible to the human observer, the interaction of gas particles in the presence of electric and gravitational fields are considered negligible as indicated by the constant velocity vectors in the image. One type of commonly known gas is steam, the gaseous state of matter is found between the liquid and plasma states, the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases which are gaining increasing attention, high-density atomic gases super cooled to incredibly low temperatures are classified by their statistical behavior as either a Bose gas or a Fermi gas. For a comprehensive listing of these states of matter see list of states of matter. The only chemical elements which are stable multi atom homonuclear molecules at temperature and pressure, are hydrogen, nitrogen and oxygen. These gases, when grouped together with the noble gases. Alternatively they are known as molecular gases to distinguish them from molecules that are also chemical compounds. The word gas is a neologism first used by the early 17th-century Flemish chemist J. B. van Helmont, according to Paracelsuss terminology, chaos meant something like ultra-rarefied water. An alternative story is that Van Helmonts word is corrupted from gahst and these four characteristics were repeatedly observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a relationship among these properties expressed by the ideal gas law. Gas particles are separated from one another, and consequently have weaker intermolecular bonds than liquids or solids. These intermolecular forces result from interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another, transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these forces varies within a substance which determines many of the physical properties unique to each gas. A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion, the drifting smoke particles in the image provides some insight into low pressure gas behavior
9.
Troposphere
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The troposphere is the lowest portion of Earths atmosphere, and is also where nearly all weather takes place. It contains approximately 75% of the mass and 99% of the total mass of water vapor. The average depths of the troposphere are 20 km in the tropics,17 km in the mid latitudes, the lowest part of the troposphere, where friction with the Earths surface influences air flow, is the planetary boundary layer. This layer is typically a few hundred meters to 2 km deep depending on the landform, atop the troposphere is the tropopause, which is the border between the troposphere and stratosphere. The tropopause is a layer, where the air temperature ceases to decrease with height. Most of the phenomena we associate with day-to-day weather occur in the troposphere, by volume, dry air contains 78. 09% nitrogen,20. 95% oxygen,0. 93% argon,0. 04% carbon dioxide, and small amounts of other gases. Air also contains an amount of water vapor. The chemical composition of the troposphere is essentially uniform, with the exception of water vapor. The source of vapor is at the surface through the processes of evaporation. Thus the proportion of water vapor is normally greatest near the surface, the pressure of the atmosphere is maximum at sea level and decreases with altitude. This is because the atmosphere is nearly in hydrostatic equilibrium. The temperature of the troposphere generally decreases as altitude increases, the rate at which the temperature decreases, − d T / d z, is called the environmental lapse rate. The ELR is nothing more than the difference in temperature between the surface and the tropopause divided by the height. The reason for this difference is that the ground absorbs most of the suns energy. Meanwhile, the radiation of heat at the top of the results in the cooling of that part of the atmosphere. The ELR assumes the atmosphere is still, but as air is heated it becomes buoyant, when a parcel of air rises, it expands, because the pressure is lower at higher altitudes. As the air expands, it pushes the surrounding air outward. As energy transfer to a parcel of air by way of heat is very slow, such a process is called an adiabatic process
10.
Weather
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Weather is the state of the atmosphere, to the degree that it is hot or cold, wet or dry, calm or stormy, clear or cloudy. Most weather phenomena occur in the lowest level of the atmosphere, Weather refers to day-to-day temperature and precipitation activity, whereas climate is the term for the averaging of atmospheric conditions over longer periods of time. When used without qualification, weather is understood to mean the weather of Earth. Weather is driven by air pressure, temperature and moisture differences between one place and another and these differences can occur due to the suns angle at any particular spot, which varies with latitude. The strong temperature contrast between polar and tropical air gives rise to the largest scale atmospheric circulations, the Hadley Cell, the Ferrel Cell, the Polar Cell, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow. Because the Earths axis is tilted relative to its orbital plane, on Earths surface, temperatures usually range ±40 °C annually. Over thousands of years, changes in Earths orbit can affect the amount and distribution of energy received by the Earth, thus influencing long-term climate. Surface temperature differences in turn cause pressure differences, higher altitudes are cooler than lower altitudes as most atmospheric heating is due to contact with the Earths surface while radiative losses to space are mostly constant. Weather forecasting is the application of science and technology to predict the state of the atmosphere for a future time and a given location. The Earths weather system is a system, as a result. Human attempts to control the weather have occurred throughout history, and there is evidence that human activities such as agriculture, studying how the weather works on other planets has been helpful in understanding how weather works on Earth. A famous landmark in the Solar System, Jupiters Great Red Spot, is a storm known to have existed for at least 300 years. However, weather is not limited to planetary bodies, a stars corona is constantly being lost to space, creating what is essentially a very thin atmosphere throughout the Solar System. The movement of mass ejected from the Sun is known as the solar wind, on Earth, the common weather phenomena include wind, cloud, rain, snow, fog and dust storms. Less common events include natural disasters such as tornadoes, hurricanes, typhoons, almost all familiar weather phenomena occur in the troposphere. Weather does occur in the stratosphere and can affect weather lower down in the troposphere, Weather occurs primarily due to air pressure, temperature and moisture differences between one place to another. These differences can occur due to the sun angle at any particular spot, in other words, the farther from the tropics one lies, the lower the sun angle is, which causes those locations to be cooler due the spread of the sunlight over a greater surface. The strong temperature contrast between polar and tropical air gives rise to the large scale atmospheric circulation cells and the jet stream, Weather systems in the mid-latitudes, such as extratropical cyclones, are caused by instabilities of the jet stream flow
