Lassen Volcanic National Park
Lassen Volcanic National Park is an American national park in northeastern California. The dominant feature of the park is Lassen Peak, the largest plug dome volcano in the world and the southernmost volcano in the Cascade Range. Lassen Volcanic National Park started as two separate national monuments designated by President Theodore Roosevelt in 1907: Cinder Cone National Monument and Lassen Peak National Monument; the source of heat for the volcanism in the Lassen area is subduction of the Gorda Plate diving below the North American Plate off the Northern California coast. The area surrounding Lassen Peak is still active with boiling mud pots and hot springs. Lassen Volcanic National Park is one of the few areas in the world where all four types of volcano can be found—plug dome, cinder cone, stratovolcano; the park is accessible via State Routes 89 and 44. SR 89 passes north-south through the park, beginning at SR 36 to the south and ending at SR 44 to the north. SR 89 passes adjacent to the base of Lassen Peak.
There are five vehicle entrances to the park: the north and south entrances on SR 89. The park can be accessed by trails leading in from the Caribou Wilderness to the east, as well as the Pacific Crest Trail, two smaller trails leading in from Willow Lake and Little Willow Lake to the south; the Lassen Chalet, a large lodge with concession facilities, was located near the southwest entrance, but was demolished in 2005. A new full-service visitor center in the same location opened to the public in 2008; the Lassen Ski Area was located near the lodge. Native Americans have inhabited the area since long; the natives knew that the peak was full of fire and water and thought it would one day blow itself apart. White immigrants in the mid-19th century used Lassen Peak as a landmark on their trek to the fertile Sacramento Valley. One of the guides to these immigrants was a Danish blacksmith named Peter Lassen, who settled in Northern California in the 1830s. Lassen Peak was named after him. Nobles Emigrant Trail was cut through the park area and passed Cinder Cone and the Fantastic Lava Beds.
Inconsistent newspaper accounts reported by witnesses from 1850 to 1851 described seeing "fire thrown to a terrible height" and "burning lava running down the sides" in the area of Cinder Cone. As late as 1859, a witness reported seeing fire in the sky from a distance, attributing it to an eruption. Early geologists and volcanologists who studied the Cinder Cone concluded the last eruption occurred between 1675 and 1700. After the 1980 eruption of Mount St. Helens, the United States Geological Survey began reassessing the potential risk of other active volcanic areas in the Cascade Range. Further study of Cinder Cone estimated the last eruption occurred between 1630 and 1670. Recent tree-ring analysis has placed the date at 1666; the Lassen area was first protected by being designated as the Lassen Peak Forest Preserve. Lassen Peak and Cinder Cone were declared as U. S. National Monuments in May 1907 by President Theodore Roosevelt. Starting in May 1914 and lasting until 1921, a series of minor to major eruptions occurred on Lassen.
These events created a new crater, released lava and a great deal of ash. Because of warnings, no one was killed, but several houses along area creeks were destroyed; because of the eruptive activity, which continued through 1917, the area's stark volcanic beauty, Lassen Peak, Cinder Cone and the area surrounding were declared a National Park on August 9, 1916. The 29-mile Main Park Road was constructed between 1925 and 1931, just 10 years after Lassen Peak erupted. Near Lassen Peak the road reaches 8,512 feet, it is not unusual for 40 ft of snow to accumulate on the road near Lake Helen and for patches of snow to last into July. In October 1972, a portion of the park was designated as Lassen Volcanic Wilderness by the US Congress; the National Park Service seeks to manage the wilderness in keeping with the Wilderness Act of 1964, with minimal developed facilities and trails. The management plan of 2003 adds that, "The wilderness experience offers a moderate to high degree of challenge and adventure."In 1974, the National Park Service took the advice of the USGS and closed the visitor center and accommodations at Manzanita Lake.
The Survey stated that these buildings would be in the way of a rockslide from Chaos Crags if an earthquake or eruption occurred in the area. An aging seismograph station remains. However, a campground and museum dedicated to Benjamin F. Loomis stands near Manzanita Lake, welcoming visitors who enter the park from the northwest entrance. After the Mount St. Helens eruption, the USGS intensified its monitoring of active and active volcanoes in the Cascade Range. Monitoring of the Lassen area includes periodic measurements of ground deformation and volcanic-gas emissions and continuous transmission of data from a local network of nine seismometers to USGS offices in Menlo Park, California. Should indications of a significant increase in volcanic activity be detected, the USGS will deploy scientists and specially designed portable monitoring instruments to evaluate the threat. In addition, the National Park Service has developed an emergency response plan that would be activated to protect the public in the event of an impending eruption.
The NPS tracks visitors by counting vehicles entering the park via in-road inductive loops at all vehicle entrances. Buses and other non-reportable vehicles are subtracted from
Eagle Lake (Lassen County)
Eagle Lake is a lake at 5,098 ft elevation in Lassen County 15 mi north of Susanville, California. An endorheic alkaline lake, it is the second largest natural lake in the state of California, United States. Eagle Lake is home to bald eagles, from which it gets its name. Eagle Lake is the only watershed; these rainbow trout grow to large sizes having evolved to live longer as low flows restrict spawning runs up their main spawning stream, Pine Creek. The average size of Eagle Lake trout can exceed 10 lb. Adults grow to a size of 17 to 18 in in three years and can live for up to 11 years. Since these Modoc Lakes are high in alkalinity, the trout have evolved to be the only known trout subspecies capable of surviving in the alkaline waters of Eagle Lake. Eagle Lake Rainbow descendants, are planted with high success in many other lakes in California; these trout were once so abundant that there was a commercial fishery for them in the late 19th century. At the same time, extensive logging and heavy livestock grazing caused Pine Creek to change from a permanent to an intermittent stream in its lower reaches.
In the early 1950s the few remaining eagle lake rainbow trout at the mouth of Pine Creek were rescued and used to start a hatchery program to maintain the species and the sport fishery. Because of the complete dependence of Eagle Lake rainbow trout on hatchery production, the American Fisheries Society considers it to be a threatened species and NatureServe has listed it as critically imperiled. Peter Moyle considers it to be one of the most endangered salmonids in California. However, a petition for listing the Eagle Lake rainbow trout as a threatened species was rejected by the U. S. Fish and Wildlife Service in 1994, a similar petition was rejected by the California State Fish and Game Commission in 2004. From 2007 to 2009 Bogard Spring Creek, a tributary to Pine Creek, was electrofished to remove non-native brook trout. Non-native fish have not survived in the lake because of its high alkalinity, although in the early 1900s during a period of higher lake levels and falling alkalinity, Largemouth bass and Brown bullhead became abundant in the lake for some years.
American white pelicans nested on Eagle Lake. They suffered from hunting by locals who mistakenly thought the pelicans ate the native trout and stopped nesting after 1932, when water was exported for agricultural irrigation and lowered the lake level by 3 meters, changing their nesting island into a less desirable peninsula. Eagle Lake was once part of a large lake on the Modoc Plateau millions of years ago; the modern lake is 15 mi long by 1.8–2.5 mi wide and is alkaline. The lake consists of three basins, two of them averaging 16–20 ft deep, the third averaging 32–65 ft and reaching a depth of nearly 98 ft; the tributaries of Eagle Lake are Cleghorn Creek, Papoose Creek, Merrill Creek, Pine Creek. Pine Creek is 39 miles long. Now an intermittent stream. In 1923 the Leon Bly Tunnel was constructed to export lake water to the Honey Lake Valley via Willow Creek, a tributary of the Susan River; the 2 mi long tunnel was cut through old lava flows but falling lake levels rendered it useless and a landslide blocked the tunnel entrance.
However, a 1990 study found that lake water still flows through the tunnel although tunnel fish are from the Willow Creek assemblage. List of lakes in California Eagle Lake Biological Field Station Wild Eagle Lake Rainbow Trout Restoration Project Video
Sierra Nevada (U.S.)
The Sierra Nevada is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies in Nevada; the Sierra Nevada is part of the American Cordillera, a chain of mountain ranges that consists of an continuous sequence of such ranges that form the western "backbone" of North America, Central America, South America and Antarctica. The Sierra runs 400 miles north-to-south, is 70 miles across east-to-west. Notable Sierra features include the largest alpine lake in North America; the Sierra is home to three national parks, twenty wilderness areas, two national monuments. These areas include Yosemite and Kings Canyon National Parks; the character of the range is shaped by its ecology. More than one hundred million years ago during the Nevadan orogeny, granite formed deep underground; the range started to uplift four million years ago, erosion by glaciers exposed the granite and formed the light-colored mountains and cliffs that make up the range.
The uplift caused a wide range of elevations and climates in the Sierra Nevada, which are reflected by the presence of five life zones. Uplift continues due to faulting caused by tectonic forces, creating spectacular fault block escarpments along the eastern edge of the southern Sierra; the Sierra Nevada has a significant history. The California Gold Rush occurred in the western foothills from 1848 through 1855. Due to inaccessibility, the range was not explored until 1912; the Sierra Nevada lies in Central and Eastern California, with a small but important spur extending into Nevada. West-to-east, the Sierra Nevada's elevation increases from 1,000 feet in the Central Valley to heights of about 14,000 feet at its crest 50–75 miles to the east; the east slope forms the steep Sierra Escarpment. Unlike its surroundings, the range receives a substantial amount of snowfall and precipitation due to orographic lift; the Sierra Nevada's irregular northern boundary stretches from the Susan River and Fredonyer Pass to the North Fork Feather River.
It represents where the granitic bedrock of the Sierra Nevada dives below the southern extent of Cenozoic igneous surface rock from the Cascade Range. It is bounded on the west by California's Central Valley and on the east by the Basin and Range Province; the southern boundary is at Tehachapi Pass. Physiographically, the Sierra is a section of the Cascade-Sierra Mountains province, which in turn is part of the larger Pacific Mountain System physiographic division; the California Geological Survey states that "the northern Sierra boundary is marked where bedrock disappears under the Cenozoic volcanic cover of the Cascade Range." The range is drained on its western slope by the Central Valley watershed, which discharges into the Pacific Ocean at San Francisco. The northern third of the western Sierra is part of the Sacramento River watershed, the middle third is drained by the San Joaquin River; the southern third of the range is drained by the Kings, Kaweah and Kern rivers, which flow into the endorheic basin of Tulare Lake, which overflows into the San Joaquin during wet years.
The eastern slope watershed of the Sierra is much narrower. From north to south, the Susan River flows into intermittent Honey Lake, the Truckee River flows from Lake Tahoe into Pyramid Lake, the Carson River runs into Carson Sink, the Walker River into Walker Lake. Although none of the eastern rivers reach the sea, many of the streams from Mono Lake southwards are diverted into the Los Angeles Aqueduct which provides water to Southern California; the height of the mountains in the Sierra Nevada increases from north to south. Between Fredonyer Pass and Lake Tahoe, the peaks range from 5,000 feet to more than 9,000 feet; the crest near Lake Tahoe is 9,000 feet high, with several peaks approaching the height of Freel Peak. Farther south, the highest peak in Yosemite National Park is Mount Lyell; the Sierra rises to 14,000 feet with Mount Humphreys near Bishop, California. Near Lone Pine, Mount Whitney is at 14,505 feet, the highest point in the contiguous United States. South of Mount Whitney, the elevation of the range dwindles.
The crest elevation is 10,000 feet near Lake Isabella, but south of the lake, the peaks reach to only a modest 8,000 feet. There are several notable geographical features in the Sierra Nevada: Lake Tahoe is a large, clear freshwater lake in the northern Sierra Nevada, with an elevation of 6,225 ft and an area of 191 sq mi. Lake Tahoe lies between a spur of the Sierra. Hetch Hetchy Valley, Yosemite Valley, Kings Canyon, Kern Canyon are examples of many glacially-scoured canyons on the west side of the Sierra. Yosemite National Park is filled with notable features such as waterfalls, granite domes, high mountains and meadows. Groves of Giant Sequoia
Susanville is the county seat of Lassen County, United States. Susanville is located on the Susan River in the southern part of the county, at an elevation of 4,186 feet; the population was 17,974 in the 2010 census, up from 13,541 in the 2000 census. Much of the population increase is related to persons held at two state prisons in the city. Susanville, a former logging and mining town, is the site of two state prisons: the California Correctional Center, a minimum-medium security facility, which opened in 1963; the Federal Correctional Institution, Herlong is nearby, having opened in 2001 The prisons and their effects on the community, including the provision of much-needed jobs, were explored in the documentary, Prison Town, USA, aired on PBS. Nearly half the adult population of Susanville works at the three prisons in the area, where 6,000 people are incarcerated, it was known as Rooptown until 1857, named for Isaac Roop, a pioneer of the Honey Lake District. Roop renamed the town Susanville in honor of his daughter in 1857.
Susanville is located at the head of Honey Lake Valley, 40 miles east of Lassen Peak. Susanville is located at 40°24′59″N 120°39′11″W; the elevation of Susanville is 4,258 feet above sea level. It is considered a gateway city to Reno on U. S. Route 395. According to the United States Census Bureau, the city has a total area of 8.0 square miles, of which 7.9 square miles is land and 1.07% is water. Eagle Lake is located 15 miles north of the town. Susanville is underlain by igneous rock, which provides the parent material for its well-drained brown stony to gravelly sandy loams or loams. On the western outskirts under forest cover, the soils are reddish brown; the most common soil series in Susanville's urban area is Springmeyer gravelly fine sandy loam. Susanville was named after daughter of Isaac Roop, an early settler, it was first called Rooptown, the present name was adopted in 1857. The Susanville US post office was established in 1860. Susanville was incorporated in 1900; the center of farming and the lumber industry, Susanville suffered from the loss of jobs as these industries changed or declined in the 20th century.
Since the late 20th century, the only area of growth in the economy has been associated with the construction and operation of two state prisons in the city and one federal prison in the area. In 2007 half of the adult population of Susanville worked in the prisons: the California Correctional Center, a minimum-medium security facility, which opened in 1963. Susanville has an alpine climate with cold winters and warm dry summers with a high degree of diurnal temperature variation. Records have been kept at several stations since 1893, including Susanville Airport and Susanville 2 SW, southwest of the town center, along with two other stations with shorter records. Average January temperatures are a high of 40.4 °F and a low of 20.8 °F. Average July temperatures are a high of 88.4 °F and a low of 49.8 °F. Temperatures reach 90 °F or higher on an average of 36.9 days annually, drop to 32 °F or lower on an average of 164.6 days annually. The highest recorded temperature in Susanville was 106 °F in July 1931, the lowest recorded temperature was −23 °F on February 1, 1956.
Annual precipitation averaged 13.44 inches from 1971 to 2000, with an average of 66 days with measurable precipitation. Susanville Airport has averaged a somewhat higher 15.04 inches between 1893 and 2012. At the airport the wettest calendar year has been 1907 with 33.51 inches and the driest 1976 with 5.33 inches, though the wettest "rain year" was from July 1937 to June 1938 with 33.01 inches as against 32.42 inches between July 1906 and June 1907 and 4.36 inches in the driest rain year from July 1975 to June 1976. The most precipitation in one month was 12.30 inches in March 1907, the most in 24 hours 5.04 inches on January 31, 1897. Annual snowfall averages 18.7 inches at Susanville 2 SW and 32.8 inches at the airport, though the median at Susanville 2 SW is only 6.5 inches. The most snowfall in one year was 89 inches in 1937, with the most in one month 65.5 inches in January 1895. The 2010 United States Census reported that Susanville had a population of 17,947; the population density was 2,238.7 people per square mile.
The racial makeup of Susanville was 11,269 White, 2,249 African American, 612 Native American, 198 Asian, 111 Pacific Islander, 2,928 from other races, 580 from two or more races. Hispanic or Latino of any race were 4,259 persons; the Census reported that 9,439 people lived in households, 108 lived in non-institutionalized group quarters, 8,400 were institutionalized. There were 3,833 households, out of which 1,357 had children under the age of 18 living in them, 1,645 were opposite-sex married couples living together, 499 had a female householder with no husband pres
A river mouth is the part of a river where the river debouches into another river, a lake, a reservoir, a sea, or an ocean. The water from a river can enter the receiving body in a variety of different ways; the motion of a river is influenced by the relative density of the river compared to the receiving water, the rotation of the earth, any ambient motion in the receiving water, such as tides or seiches. If the river water has a higher density than the surface of the receiving water, the river water will plunge below the surface; the river water will either form an underflow or an interflow within the lake. However, if the river water is lighter than the receiving water, as is the case when fresh river water flows into the sea, the river water will float along the surface of the receiving water as an overflow. Alongside these advective transports, inflowing water will diffuse. At the mouth of a river, the change in flow condition can cause the river to drop any sediment it is carrying; this sediment deposition can generate a variety of landforms, such as deltas, sand bars and tie channels.
Many places in the United Kingdom take their names from their positions at the mouths of rivers, such as Plymouth and Great Yarmouth. Confluence River delta Estuary Liman
Geographic coordinate system
A geographic coordinate system is a coordinate system that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position and two or three of the numbers represent a horizontal position. A common choice of coordinates is latitude and elevation. To specify a location on a plane requires a map projection; the invention of a geographic coordinate system is credited to Eratosthenes of Cyrene, who composed his now-lost Geography at the Library of Alexandria in the 3rd century BC. A century Hipparchus of Nicaea improved on this system by determining latitude from stellar measurements rather than solar altitude and determining longitude by timings of lunar eclipses, rather than dead reckoning. In the 1st or 2nd century, Marinus of Tyre compiled an extensive gazetteer and mathematically-plotted world map using coordinates measured east from a prime meridian at the westernmost known land, designated the Fortunate Isles, off the coast of western Africa around the Canary or Cape Verde Islands, measured north or south of the island of Rhodes off Asia Minor.
Ptolemy credited him with the full adoption of longitude and latitude, rather than measuring latitude in terms of the length of the midsummer day. Ptolemy's 2nd-century Geography used the same prime meridian but measured latitude from the Equator instead. After their work was translated into Arabic in the 9th century, Al-Khwārizmī's Book of the Description of the Earth corrected Marinus' and Ptolemy's errors regarding the length of the Mediterranean Sea, causing medieval Arabic cartography to use a prime meridian around 10° east of Ptolemy's line. Mathematical cartography resumed in Europe following Maximus Planudes' recovery of Ptolemy's text a little before 1300. In 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, England as the zero-reference line; the Dominican Republic voted against the motion, while Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911.
In order to be unambiguous about the direction of "vertical" and the "horizontal" surface above which they are measuring, map-makers choose a reference ellipsoid with a given origin and orientation that best fits their need for the area they are mapping. They choose the most appropriate mapping of the spherical coordinate system onto that ellipsoid, called a terrestrial reference system or geodetic datum. Datums may be global, meaning that they represent the whole Earth, or they may be local, meaning that they represent an ellipsoid best-fit to only a portion of the Earth. Points on the Earth's surface move relative to each other due to continental plate motion and diurnal Earth tidal movement caused by the Moon and the Sun; this daily movement can be as much as a metre. Continental movement can be up to 10 m in a century. A weather system high-pressure area can cause a sinking of 5 mm. Scandinavia is rising by 1 cm a year as a result of the melting of the ice sheets of the last ice age, but neighbouring Scotland is rising by only 0.2 cm.
These changes are insignificant if a local datum is used, but are statistically significant if a global datum is used. Examples of global datums include World Geodetic System, the default datum used for the Global Positioning System, the International Terrestrial Reference Frame, used for estimating continental drift and crustal deformation; the distance to Earth's center can be used both for deep positions and for positions in space. Local datums chosen by a national cartographical organisation include the North American Datum, the European ED50, the British OSGB36. Given a location, the datum provides the latitude ϕ and longitude λ. In the United Kingdom there are three common latitude and height systems in use. WGS 84 differs at Greenwich from the one used on published maps OSGB36 by 112 m; the military system ED50, used by NATO, differs from about 120 m to 180 m. The latitude and longitude on a map made against a local datum may not be the same as one obtained from a GPS receiver. Coordinates from the mapping system can sometimes be changed into another datum using a simple translation.
For example, to convert from ETRF89 to the Irish Grid add 49 metres to the east, subtract 23.4 metres from the north. More one datum is changed into any other datum using a process called Helmert transformations; this involves converting the spherical coordinates into Cartesian coordinates and applying a seven parameter transformation, converting back. In popular GIS software, data projected in latitude/longitude is represented as a Geographic Coordinate System. For example, data in latitude/longitude if the datum is the North American Datum of 1983 is denoted by'GCS North American 1983'; the "latitude" of a point on Earth's surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the Equator and to each other; the North Pole is 90° N. The 0° parallel of latitude is designated the Equator, the fun