U.S. National Geodetic Survey
"United States Coast Survey" and "United States Coast and Geodetic Survey" redirect here. They are former scientific agencies of the United States government which should not be confused with the United States Coast Guard, a seagoing U. S. government law enforcement and safety agency, the modern Coast Survey, a U. S. government agency that makes nautical charts, or the United States Geological Survey, a U. S. government agency that studies earth science and makes topographical maps. The National Geodetic Survey the United States Survey of the Coast, United States Coast Survey, United States Coast and Geodetic Survey, is a United States federal agency that defines and manages a national coordinate system, providing the foundation for transportation and communication. Since its foundation in its present form in 1970, it has been part of the National Oceanic and Atmospheric Administration, of the United States Department of Commerce; the National Geodetic Survey's history and heritage are intertwined with those of other NOAA offices.
As the U. S. Coast Survey and U. S. Coast and Geodetic Survey, the agency operated a fleet of survey ships, from 1917 the Coast and Geodetic Survey was one of the uniformed services of the United States with its own corps of commissioned officers. Upon the creation of the Environmental Science Services Administration in 1965, the commissioned corps was separated from the Survey to become the Environmental Science Services Administration Corps. Upon the creation of NOAA in 1970, the ESSA Corps became the National Oceanic and Atmospheric Administration Commissioned Officer Corps. Thus, the National Geodetic Survey's ancestor organizations are the ancestors of today's NOAA Corps and Office of Coast Survey and are among the ancestors of today's NOAA fleet. In addition, today's National Institute of Standards and Technology, although long since separated from the Survey, got its start as the Survey's Office of Weights and Measures; the National Geodetic Survey is an office of NOAA's National Ocean Service.
Its core function is to maintain the National Spatial Reference System, "a consistent coordinate system that defines latitude, height, scale and orientation throughout the United States." NGS is responsible for defining the NSRS and its relationship with the International Terrestrial Reference Frame. The NSRS enables precise and accessible knowledge of where things are in the United States and its territories; the NSRS may be divided into its geometric and physical components. The official geodetic datum of the United States, NAD83 defines the geometric relationship between points within the United States in three-dimensional space; the datum may be accessed via NGS's network of survey marks or through the Continuously Operating Reference Station network of GPS reference antennas. NGS is responsible for computing the relationship between NAD83 and the ITRF; the physical components of the NSRS are reflected in its height system, defined by the vertical datum NAVD88. This datum is a network of orthometric heights obtained through spirit leveling.
Because of the close relationship between height and Earth's gravity field, NGS collects and curates terrestrial gravity measurements and develops regional models of the geoid and its slope, the deflection of the vertical. NGS is responsible for ensuring the accuracy of the NSRS over time as the North American plate rotates and deforms over time due to crustal strain, post-glacial rebound, elastic deformation of the crust, other geophysical phenomena. NGS will release new datums in 2022; the North American Terrestrial Reference Frame of 2022 will supersede NAD83 in defining the geometric relationship between the North American plate and the ITRF. United States territories on the Pacific and Mariana plates will have their own respective geodetic datums; the North American-Pacific Geopotential Datum of 2022 will separately define the height system of the United States and its territories, replacing NAVD88. It will use a geoid model accurate to 1 centimeter to relate orthometric height to ellipsoidal height measured by GPS, eliminating the need for future leveling projects.
This geoid model will be based on airborne and terrestrial gravity measurements collected by NGS's GRAV-D program as well as satellite-based gravity models derived from observations collected by GRACE, GOCE, satellite altimetry missions. NGS provides a number of other public services, it maps changing shorelines in the United States and provides aerial imagery of regions affected by natural disasters, enabling rapid damage assessment by emergency managers and members of the public. The Online Positioning and User Service processes user-input GPS data and outputs position solutions within the NSRS; the agency offers other tools for conversion between datums. The original predecessor agency of the National Geodetic Survey was the United States Survey of the Coast, created within the United States Department of the Treasury by an Act of Congress on February 10, 1807, to conduct a "Survey of the Coast." The Survey of the Coast, the United States government's first scientific agency, represented the interest of the administration of President Thomas Jefferson in science and the stimulation of international trade by using scientific surveying methods to chart t
San Francisco volcanic field
The San Francisco volcanic field is an area of volcanoes in northern Arizona, north of Flagstaff, USA. The field covers 1,800 square miles of the southern boundary of the Colorado Plateau; the field contains 600 volcanoes ranging in age from nearly 6 million years old to less than 1,000 years, of which Sunset Crater is the youngest. The highest peak in the field is Humphreys Peak, at Flagstaff's northern perimeter: the peak is Arizona's highest at 12,633 feet and is a part of the San Francisco Peaks, an extinct stratovolcano complex; the volcanic field seems to have formed from a geological hotspot. As the North American plate moves over the spot, new volcanoes appear. Thus, the newest volcanoes are at the east side of the field. Most of the volcanoes are basalt cinder cones, but there are large lava domes consisting of rhyolite and dacite. Given that Sunset Crater is such a young volcanic feature of this area and that eruptions have occurred every several thousands of years in frequency, it is that there will be a future eruption in the San Francisco Volcanic field.
However, it is impossible to predict when and where a new eruption might occur. The United States Geological Survey does say that a future eruption would be in the eastern side of the volcanic field, where the most recent volcanic activity has occurred; such an eruption is to be small and pose little hazard due to the remoteness of the area. Popular tourist and hiking destinations in the volcanic field include the Kendrick Mountain Wilderness, 20 miles northwest of Flagstaff. Areas of the volcanic field have been used by NASA for testing techniques for exploration in a simulated extraterrestrial terrain environment. NASA has conducted the Desert Research and Technology Studies tests here. List of volcanoes in the United States USGS fact sheet about the San Francisco volcanic field Satellite view of San Francisco Volcanic Field
Fortification Hill is a prominence adjacent to Lake Mead in the Lake Mead National Recreation Area. It is near a southern section of Lake Mead, just northeast of Hoover Dam, it can be seen eastward across Las Vegas Bay or from the two northern mountain terminuses of Eldorado Mountains, or the Black Mountains. The mountain prominence is plateau-like, or mesa-like with its highpoint at the southeast terminus, sloping north and northwestwards toward Lake Mead; the prominence is 3,719 feet. The flat mountaintop, sloping northwards is composed of Tertiary basaltic lava flows. Black Mountains Eldorado Mountains List of mountains of Arizona by height Larger photo from the trailhead. Peakbagger.com. Geologic History of Lake Mead National Recreation Area. USGS. "Fortification Hill". SummitPost.org. "Fortification Hill". Geographic Names Information System. United States Geological Survey
James Turrell is an American artist concerned with Light and Space. Turrell was a MacArthur Fellow in 1984. Turrell is best known for his work in progress, Roden Crater, a natural cinder cone crater located outside Flagstaff, that he is turning into a massive naked-eye observatory. James Turrell was born in California, his father, Archibald Milton Turrell, was educator. His mother, Margaret Hodges Turrell, trained as a medical doctor and worked in the Peace Corps, his parents were Quakers. Turrell obtained a pilot's license. Registered as a conscientious objector during the Vietnam War, he ended up flying Buddhist monks out of Chinese-controlled Tibet; some writers have suggested. For years he restored antique airplanes to support his "art habit", he received a BA degree from Pomona College in perceptual psychology in 1965 and studied mathematics and astronomy there. Turrell enrolled in the graduate Studio Art program at the University of California, Irvine in 1966, where he began making work using light projections.
His studies at the University of California, Irvine were interrupted in 1966, when he was arrested for coaching young men to avoid the Vietnam draft. He spent about a year in jail, he received an MA degree in art from Claremont Graduate University. In 2004, he was awarded an honorary doctorate by Haverford College. In 1966, Turrell began experimenting with light in his Santa Monica studio, the Mendota Hotel, at a time when the so-called Light and Space group of artists in Los Angeles, including Robert Irwin, Mary Corse and Doug Wheeler, was coming into prominence. By covering the windows and only allowing prescribed amounts of light from the street outside to come through the openings, Turrell created his first light projections. In Shallow Space Constructions he used screened partitions, allowing a radiant effusion of concealed light to create an artificially flattened effect within the given space; that same year, he participated in the Los Angeles County Museum's Art and Technology Program, investigating perceptual phenomena with the artist Robert Irwin and psychologist Edward Wortz.
In 1969, he made sky drawings with Sam Francis, using colored skywriting smoke and cloud-seeding materials. A pivotal environment Turrell developed from 1969 to 1974, The Mendota Stoppages, used several rooms in the former Mendota Hotel in Santa Monica which were sealed off, with the window apertures controlled by the artist to allow natural and artificial light to enter the darkened spaces in specific ways. Turrell is best known for his work in progress, Roden Crater, he acquired an extinct cinder cone volcano located outside Flagstaff, Arizona, in 1979. Since he has spent decades moving tons of dirt and building tunnels and apertures to turn this crater into a massive naked-eye observatory for experiencing celestial phenomena. Although he works in the American desert, Turrell does not consider himself an earthworks artist like Robert Smithson or Michael Heizer: "You could say I'm a mound builder: I make things that take you up into the sky, but it's not about the landforms. I'm working to bring celestial objects like the sun and moon into the spaces that we inhabit."
He added: "I apprehend light — I make events that shape or contain light."The completion date for the Crater has been pushed back several times for funding and construction reasons, with the artist missing early targets in the 1990s. The last time Turrell or his team went on record talking about a completion date, the goal was 2011. During May 2015, Roden Crater was open to a select group of 80 people, as part of a fund raiser, by allowing visits of 20 people per day during the course of four days, at a cost of $6,500 per person; as Roden Crater has been long shrouded in secrecy, fans have attempted to sneak in without the artist's permission. Some have succeeded. In the 1970s, Turrell began his series of "skyspaces" enclosed spaces open to the sky through an aperture in the roof. A Skyspace is an enclosed room large enough for 15 people. Inside, the viewers sit on benches along the edge to view the sky through an opening in the roof; as a lifelong Quaker, Turrell designed the Live Oak Meeting House for the Society of Friends, with an opening or skyhole in the roof, wherein the notion of light takes on a decidedly religious connotation..
His work Meeting at P. S. 1, which consists of a square room with a rectangular opening cut directly into the ceiling, is a recreation of such a meeting house. In 2013, Turrell created another Quaker skyspace, Greet the Light, at the newly rebuilt Chestnut Hill Friends Meeting in Philadelphia. In a New York Times article on L. A. collectors building skyspaces in their backyards, Jori Finkel describes a skyspace as a " celestial viewing room designed to create the rather magical illusion that the sky is within reach -- stretched like a canvas across an opening in the ceiling."In 1992, James Turrell's Irish Sky Garden opened at the Liss Ard Estate, Skibbereen, Co Cork, Ireland. The giant earth and stoneworks has a crater at its center. A visitor enters through a doorway in the perimeter of the rim, walks through a passage and climbs stairs to enter lies on the central plinth and looks upwards to experience the sky framed by the rim of the crater. "The most important thing i
The Cerbat Mountains is a mountain range in Mohave County in northwest Arizona north of Kingman. The Cerbat Mountains and the White Hills adjacent north, are the dividing ranges between the Detrital Valley west, the Hualapai Valley east, it is a 23 mi long range trending northwest-southeast. It lies directly east of the 130-mile long Black Mountains range and is separated by the Sacramento Valley bordering southwest of Kingman through which Interstate 40 turns south and west to meet Needles, California. A series of peaks can be found towards the southern end of the range, including Packsaddle Mountain at 6,431 feet, Cherum Peak at 6,983 feet; the northern section of the Cerbat Mountains is composed of the Mount Tipton Wilderness, with Mount Tipton being its peak at 7,148 feet. The Dolan Springs community is at the base of the wilderness on the northwestern side of the Cerbat Mountains; the "Mineral Park mine", a large copper and turquoise mine, is located in the Cerbat Mountains 14 miles northwest of Kingman, Arizona.
List of mountain ranges of Arizona List of LCRV Wilderness Areas
A summit is a point on a surface, higher in elevation than all points adjacent to it. The topographic terms acme, apex and zenith are synonymous; the term top is used only for a mountain peak, located at some distance from the nearest point of higher elevation. For example, a big massive rock next to the main summit of a mountain is not considered a summit. Summits near a higher peak, with some prominence or isolation, but not reaching a certain cutoff value for the quantities, are considered subsummits of the higher peak, are considered part of the same mountain. A pyramidal peak is an exaggerated form produced by ice erosion of a mountain top. Summit may refer to the highest point along a line, trail, or route; the highest summit in the world is Everest with height of 8844.43 m above sea level. The first official ascent was made by Sir Edmund Hillary, they reached the mountain`s peak in 1953. Whether a highest point is classified as a summit, a sub peak or a separate mountain is subjective; the UIAA definition of a peak is.
Otherwise, it's a subpeak. In many parts of the western United States, the term summit refers to the highest point along a road, highway, or railroad. For example, the highest point along Interstate 80 in California is referred to as Donner Summit and the highest point on Interstate 5 is Siskiyou Mountain Summit. A summit climbing differs from the common mountaineering. Summit expedition requires: 1+ year of training, a good physical shape, a special gear. Although a huge part of climber’s stuff can be left and taken at the base camps or given to porters, there is a long list of personal equipment. In addition to common mountaineers’ gear, Summit climbers need to take Diamox and bottles of oxygen. There are special requirements for crampons, ice axe, rappel device, etc. Geoid Hill – Landform that extends above the surrounding terrain Nadir Summit accordance Peak finder Summit Climbing Gear List
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, gases to escape from a magma chamber below the surface. Earth's volcanoes occur because its crust is broken into 17 major, rigid tectonic plates that float on a hotter, softer layer in its mantle. Therefore, on Earth, volcanoes are found where tectonic plates are diverging or converging, most are found underwater. For example, a mid-oceanic ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can form where there is stretching and thinning of the crust's plates, e.g. in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande Rift in North America. This type of volcanism falls under the umbrella of "plate hypothesis" volcanism. Volcanism away from plate boundaries has been explained as mantle plumes; these so-called "hotspots", for example Hawaii, are postulated to arise from upwelling diapirs with magma from the core–mantle boundary, 3,000 km deep in the Earth.
Volcanoes are not created where two tectonic plates slide past one another. Erupting volcanoes can pose many hazards, not only in the immediate vicinity of the eruption. One such hazard is that volcanic ash can be a threat to aircraft, in particular those with jet engines where ash particles can be melted by the high operating temperature. Large eruptions can affect temperature as ash and droplets of sulfuric acid obscure the sun and cool the Earth's lower atmosphere. 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 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; because the crust is thin at these ridges due to the pull of the tectonic plates, the release of pressure leads to adiabatic expansion and the partial melting of the mantle, causing volcanism and creating new oceanic crust.
Most divergent plate boundaries are at the bottom of the oceans. Black smokers are evidence of this kind of volcanic activity. Where the mid-oceanic ridge is above sea-level, volcanic islands are formed. Subduction zones are places where two plates an oceanic plate and a continental plate, collide. In this case, the oceanic 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 melting temperature of the overlying mantle wedge, thus creating magma; this magma tends to be viscous because of its high silica content, so it does not attain the surface but cools and solidifies at depth. When it does reach the surface, however, a volcano is formed. Typical examples are the volcanoes in the Pacific Ring of Fire. Hotspots are volcanic areas believed to be formed by mantle plumes, which are hypothesized to be columns of hot material rising from the core-mantle boundary in a fixed space that causes large-volume melting.
Because tectonic plates move across them, each volcano becomes dormant and is re-formed as the plate advances over the postulated plume. The Hawaiian Islands are said to have been formed in such a manner; this theory, has been doubted. The most common perception of a volcano is of a conical mountain, spewing lava and poisonous gases from a crater at its summit; the features of volcanoes are much more complicated and their structure and behavior depends on a number of factors. Some volcanoes have rugged peaks formed by lava domes rather than a summit crater while others have landscape features such as massive plateaus. Vents that issue volcanic material and gases can develop anywhere on the landform and may give rise to smaller cones such as Puʻu ʻŌʻō on a flank of Hawaii's Kīlauea. Other types of volcano include cryovolcanoes on some moons of Jupiter and Neptune. Active mud volcanoes tend to involve temperatures much lower than those of igneous volcanoes except when the mud volcano is a vent of an igneous volcano.
Volcanic fissure vents are linear fractures through which lava emerges. Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent, they do not explode catastrophically. Since low-viscosity magma is low in silica, shield volcanoes are more common in oceanic than continental settings; the Hawaiian volcanic chain is a series of shield cones, they are common in Iceland, as well. Lava domes are built by slow eruptions of viscous lava, they are sometimes formed within the crater of a previous volcanic eruption, as in the case of Mount Saint Helen