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Payson D. Sheets
Payson D. Sheets is an American archaeologist, Mayanist, and professor of anthropology at the University of Colorado Boulder. He is primarily known for his research in Pre-Columbian Mesoamerica and Lower Central America, most importantly for his work on the Maya civilization at Joya de Cerén in El Salvador (although he has worked throughout the western United States, Canada, Panama, Guatemala, Costa Rica, and Nicaragua). He specializes in Mesoamerican archaeology, lithic technology, ancient adaptations, geophysical applications, hazards research (sudden environmental change – particularly volcanic eruptions), and remote sensing. Education Sheets received his B.A. in 1967 and M.A. in 1969 at the University of Colorado and Ph.D. in 1974 at the University of Pennsylvania. Field work His largest known body of research comes from the archaeology of the Maya site of Cerén, or Joya de Cerén, in the Zapotitan Valley of El Salvador which has been ongoing since it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archaeologist
Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landscapes. Archaeology can be considered both a social science and a branch of the humanities. It is usually considered an independent academic discipline, but may also be classified as part of anthropology (in North America – the four-field approach), history or geography. Archaeologists study human prehistory and history, from the development of the first stone tools at Lomekwi in East Africa 3.3 million years ago up until recent decades. Archaeology is distinct from palaeontology, which is the study of fossil remains. Archaeology is particularly important for learning about prehistoric societies, for which, by definition, there are no written records. Prehistory includes over 99% of the human past, from the Paleolithic until the adve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geophysical
Geophysics () is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment, and the use of quantitative methods for their analysis. The term ''geophysics'' sometimes refers only to solid earth applications: Earth's shape; its gravitational and magnetic fields; its internal structure and composition; its dynamics and their surface expression in plate tectonics, the generation of magmas, volcanism and rock formation. However, modern geophysics organizations and pure scientists use a broader definition that includes the water cycle including snow and ice; fluid dynamics of the oceans and the atmosphere; electricity and magnetism in the ionosphere and magnetosphere and solar-terrestrial physics; and analogous problems associated with the Moon and other planets. Gutenberg, B., 1929, Lehrbuch der Geophysik. Leipzig. Berlin (Gebruder Borntraeger). Runcorn, S.K, (editor-in-chief), 1967, International ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Landsat
The Landsat program is the longest-running enterprise for acquisition of satellite imagery of Earth. It is a joint NASA / USGS program. On 23 July 1972, the Earth Resources Technology Satellite was launched. This was eventually renamed to Landsat 1 in 1975. The most recent, Landsat 9, was launched on 27 September 2021. The instruments on the Landsat satellites have acquired millions of images. The images, archived in the United States and at Landsat receiving stations around the world, are a unique resource for global change research and applications in agriculture, cartography, geology, forestry, regional planning, surveillance and education, and can be viewed through the U.S. Geological Survey (USGS) "EarthExplorer" website. Landsat 7 data has eight spectral bands with spatial resolutions ranging from ; the temporal resolution is 16 days. Landsat images are usually divided into scenes for easy downloading. Each Landsat scene is about 115 miles long and 115 miles wide (or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synthetic Aperture Radar
Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars. SAR is typically mounted on a moving platform, such as an aircraft or spacecraft, and has its origins in an advanced form of side looking airborne radar (SLAR). The distance the SAR device travels over a target during the period when the target scene is illuminated creates the large ''synthetic'' antenna aperture (the ''size'' of the antenna). Typically, the larger the aperture, the higher the image resolution will be, regardless of whether the aperture is physical (a large antenna) or synthetic (a moving antenna) – this allows SAR to create high-resolution images with comparatively small physical antennas. For a fixed antenna size and orientation, objects which are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Infrared Spectroscopy
Thermal infrared spectroscopy (TIR spectroscopy) is the subset of infrared spectroscopy that deals with radiation emitted in the infrared part of the electromagnetic spectrum. The emitted infrared radiation, though similar to blackbody radiation, is different in that the radiation is banded at characteristic vibrations in the material. The method measures the thermal infrared radiation emitted (as opposed to being transmitted or reflected) from a volume or surface. This method is commonly used to identify the composition of surface by analyzing its spectrum and comparing it to previously measured materials. It is particularly suited to airborne and spaceborne applications. Thermal infrared spectrometers Airborne *TIMS: a multispectral radiometer flown on C-130, ER-2, and the Stennis Learjet aircraft. *SEBASS: a hyperspectral sensor developed and operated by The Aerospace Corporation. *Hyper-Cam: a hyperspectral thermal infrared camera developed by Telops. *OWL: a hyperspectr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
LiDAR
Lidar (, also LIDAR, or LiDAR; sometimes LADAR) is a method for determining ranges (variable distance) by targeting an object or a surface with a laser and measuring the time for the reflected light to return to the receiver. It can also be used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light. It has terrestrial, airborne, and mobile applications. ''Lidar'' is an acronym of "light detection and ranging" or "laser imaging, detection, and ranging". It is sometimes called 3-D laser scanning, a special combination of 3-D scanning and laser scanning. Lidar is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swath mapping (ALSM), and laser altimetry. It is also used in control and navigation for som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infrared Photography
''Top:'' tree photographed in the near infrared range. ''Bottom:'' same tree in the visible part of the spectrum. In infrared photography, the film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Film is usually sensitive to visible light too, so an infrared-passing filter is used; this lets infrared (IR) light pass through to the camera, but blocks all or most of the visible light spectrum (the filter thus looks black or deep red). ("Infrared filter" may refer either to this type of filter or to one that blocks infrared but passes other wavelengths.) When these filters are used together with infrared-sensitive film or sensors, "in-camera effects" can be obtained; false-color or black-and-white images with a dreamlike or sometimes lurid appearance kn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Ash
Volcanic ash consists of fragments of rock, mineral crystals, and volcanic glass, created during volcano, volcanic eruptions and measuring less than 2 mm (0.079 inches) in diameter. The term volcanic ash is also often loosely used to refer to all explosive eruption products (correctly referred to as ''tephra''), including particles larger than 2 mm. Volcanic ash is formed during explosive volcanic eruptions when dissolved gases in magma expand and escape violently into the atmosphere. The force of the gases 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, causing the water to explosively flash to steam leading to shattering of magma. Once in the air, ash is transported by wind up to thousands of kilometres away. Due to its wide dispersal, ash can have a number of impacts on society, including animal a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Colorado
The University of Colorado (CU) is a system of public universities in Colorado. It consists of four institutions: University of Colorado Boulder, University of Colorado Colorado Springs, University of Colorado Denver, and the University of Colorado Anschutz Medical Campus. It is governed by the elected, nine-member board of regents. Campuses * The University of Colorado Boulder (CU Boulder) is the flagship university of the University of Colorado System in Boulder, Colorado. Founded in 1876, the university has more than 33,000 undergraduate and graduate students. It offers more than 2,500 courses in more than 150 areas of study through its nine colleges and schools. * The University of Colorado Colorado Springs (UCCS) is the fastest growing of the three campuses with an undergraduate and graduate student population of about 12,000 students. It offers 45 bachelor's, 22 master's, and five doctoral degree programs through its six colleges. The campus is located in central Colorad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Loma Caldera
The San Salvador Volcano (also known as Quezaltepeque or El Boquerón) is a stratovolcano situated northwest to the city of San Salvador. The crater has been nearly filled with a relatively newer edifice, the Boquerón volcano. San Salvador is adjacent to the volcano and the western section of the city actually lies among its slopes. Due to this close proximity, any geological activity of the volcano, whether eruptive or not, has the potential to result in catastrophic destruction and death to the city. Despite this, the volcano is iconic of the city, and several TV and radio antennas are situated on the El Picacho peaks and the crater of Boqueron. El Picacho, the prominent peak is the highest elevation (1,960 meters altitude). Boquerón edifice The main edifice, known as the Boquerón edifice, formed between 700 and 1,000 years ago, filling up a former caldera. The crescent-shaped ridge on the northeast side of the volcano is a remnant of the caldera rim. The lavas of the B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pompeii
Pompeii (, ) was an ancient city located in what is now the ''comune'' of Pompei near Naples in the Campania region of Italy. Pompeii, along with Herculaneum and many villas in the surrounding area (e.g. at Boscoreale, Stabiae), was buried under of volcanic ash and pumice in the Eruption of Mount Vesuvius in 79 AD. Largely preserved under the ash, the excavated city offered a unique snapshot of Roman life, frozen at the moment it was buried, although much of the detailed evidence of the everyday life of its inhabitants was lost in the excavations. It was a wealthy town, with a population of ca. 11,000 in AD 79, enjoying many fine public buildings and luxurious private houses with lavish decorations, furnishings and works of art which were the main attractions for the early excavators. Organic remains, including wooden objects and human bodies, were interred in the ash. Over time, they decayed, leaving voids that archaeologists found could be used as moulds to make plaste ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Pennsylvania
The University of Pennsylvania (also known as Penn or UPenn) is a private research university in Philadelphia. It is the fourth-oldest institution of higher education in the United States and is ranked among the highest-regarded universities by numerous organizations and scholars. While the university dates its founding to 1740, it was created by Benjamin Franklin and other Philadelphia citizens in 1749. It is a member of the Ivy League. The university has four undergraduate schools as well as twelve graduate and professional schools. Schools enrolling undergraduates include the College of Arts and Sciences, the School of Engineering and Applied Science, the Wharton School, and the School of Nursing. Among its highly ranked graduate schools are its law school, whose first professor wrote the first draft of the United States Constitution, its medical school, the first in North America, and Wharton, the first collegiate business school. Penn's endowment is US$20.7 billio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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