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At least 487 records · Page 27Linked to original sources
USGS2023

2022 Crustal Deformation Modeling Workshop Report

The 2022 Crustal Deformation Modeling Workshop was held June 20–24 at the Colorado School of Mines in Golden, Colorado. The workshop included two days of tutorials on the use of the open-source software PyLith for crustal deformation modeling followed by three days of science talks and discussions. The workshop focused on three primary themes: (1) Earthquake cycle modeling; (2) Inversions for fault slip; and (3) Faulting, fluids, and surface loading. The talks highlighted how computational models provide insight into intriguing observations of Earth and planetary behavior. These included (1) earthquake synchronization of rupture patches due to their close proximity to each other, (2) the influence of fault geometry and damage zones on hypocenter depth and rupture propagation, (3) a lack of steady-state faulting behavior due to long time scales for grain size evolution in the mid-crust, (4) crustal deformation due to tidal, hydrological, and atmospheric loads, and (5) plumes of gas and icy particles due to tidal driven faulting on Enceladus (one of Saturn’s moons). The talks also described new computational modeling capabilities for incorporating complex geologic structure into Bayesian inversions for fault slip and efficient implementation of earthquake cycle models using a symmetric interior discontinuous Galerkin method. The complete agenda is available on the Computational Infrastructure for Geodynamic (CIG) website.

Report↗
USGS2010

Self calibration of small and medium format digital cameras

The knowledge of a camera’s interior orientation parameters are a prerequisite for the camera to be used in any precision photogrammetric project. Historically, the interior orientation parameters have been determined by analyzing the measured ground 3D coordinates of photo-identifiable targets, and their 2D (image) coordinates from multiple images of these targets. Camera self calibration, on the other hand, uses targets on a scene that have not been measured before. In this research, we will briefly discuss existing self calibration techniques, and present two methods for camera self calibration that are being used at the U.S. Geological Survey’s Earth Resources Observation and Science (EROS) Data Center. The first method, developed by Pictometry (augmented by Dr C.S. Fraser), uses a series of coded targets on a cage. The coded targets form different patterns that are imaged from nine different locations with differing camera orientations. A free network solution using collinearity equations is used to determine the calibration parameters. The coded targets are placed on the cage in three different planes, which allows for a robust calibration procedure. The USGS/EROS has developed an inexpensive method for calibration, particularly for calibrating short focal length cameras. In this case, the coded targets are pasted on a small prototype box and imaged from different locations and camera orientations. The design of the box is discussed, and the results of the box and the cage calibrations are compared and analyzed.

Conference Paper↗
USGS2008

Development of Landsat-5 thematic mapper internal calibrator gain and offset table

The National Landsat Archive Production System (NLAPS) has been the primary processing system for Landsat data since U.S. Geological Survey (USGS) Earth Resources Observation and Science Center (EROS) started archiving Landsat data. NLAPS converts raw satellite data into radiometrically and geometrically calibrated products. NLAPS has historically used the Internal Calibrator (IC) to calibrate the reflective bands of the Landsat-5 Thematic Mapper (TM), even though the lamps in the IC were less stable than the TM detectors, as evidenced by vicarious calibration results. In 2003, a major effort was made to model the actual TM gain change and to update NLAPS to use this model rather than the unstable IC data for radiometric calibration. The model coefficients were revised in 2007 to reflect greater understanding of the changes in the TM responsivity. While the calibration updates are important to users with recently processed data, the processing system no longer calculates the original IC gain or offset. For specific applications, it is useful to have a record of the gain and offset actually applied to the older data. Thus, the NLAPS calibration database was used to generate estimated daily values for the radiometric gain and offset that might have been applied to TM data. This paper discusses the need for and generation of the NLAPS IC gain and offset tables. A companion paper covers the application of and errors associated with using these tables.

Conference Paper↗
USGS2003

Delivering data for The National Map

The National Map aims at delivering current, nationwide views of regional and local data, synthesized into a single presentation. A key method of achieving this is the use of satellite data, aerial photographs, and derivative products to maintain up-to-date maps. The Earth Resources Observation Systems (EROS) Data Center (EDC) archives several large orthoimagery datasets, along with reference datasets, and is the main distributor of elevation data for this effort. The EDC is using the raster and reference datasets to create OpenGIS Consortium and ArcGIS** compatible map services. The datasets are processed into seamless tables within an Arc Spatial Database Engine residing on an Oracle database. This database resides on a Solaris server accessed through an Arc Internet Map Server running on Windows 2000 machines to create online map services. A Cisco switch that uses load balancing for reliability handles client requests. This system has a theoretical capacity to render of 300,000 to 400,000 images and to provide 600 to 1,500 data extractions per day. Over the last 6 months, this system has delivered more than 4.8 million maps online and 2.6 terabytes of actual data in downloads and media.

Conference Paper↗
USGS2022

Fifty years of Landsat science and impacts

Since 1972, the Landsat program has been continually monitoring the Earth, to now provide 50 years of digital, multispectral, medium spatial resolution observations. Over this time, Landsat data were crucial for many scientific and technical advances. Prior to the Landsat program, detailed, synoptic depictions of the Earth's surface were rare, and the ability to acquire and work with large datasets was limited. The early years of the Landsat program delivered a series of technological breakthroughs, pioneering new methods, and demonstrating the ability and capacity of digital satellite imagery, creating a template for other global Earth observation missions and programs. Innovations driven by the Landsat program have paved the way for subsequent science, application, and policy support activities. The economic and scientific value of the knowledge gained through the Landsat program has been long recognized, and despite periods of funding uncertainty, has resulted in the program's 50 years of continuity, as well as substantive and ongoing improvements to payload and mission performance. Free and open access to Landsat data, enacted in 2008, was unprecedented for medium spatial resolution Earth observation data and substantially increased usage and led to a proliferation of science and application opportunities. Here, we highlight key developments over the past 50 years of the Landsat program that have influenced and changed our scientific understanding of the Earth system. Major scientific and programmatic impacts have been realized in the areas of agricultural crop mapping and water use, climate change drivers and impacts, ecosystems and land cover monitoring, and mapping the changing human footprint. The introduction of Landsat collection processing, coupled with the free and open data policy, facilitated a transition in Landsat data usage away from single images and towards time series analyses over large areas and has fostered the widespread use of science-grade data. The launch of Landsat-9 on September 27, 2021, and the advanced planning of its successor mission, Landsat-Next, underscore the sustained institutional support for the program. Such support and commitment to continuity is recognition of both the historic impact the program, and the future potential to build upon Landsat's remarkable 50-year legacy.

Remote Sensing of Environment↗
USGS2012

Observations of the lunar regolith and the Earth from the television camera on Surveyor 7

Surveyor 7, the last spacecraft of the Surveyor series, landed about 30 km north of the rim crest of Tycho, one of the most prominent and well-known features in the southern part of the moon. About 21,000 pictures were transmitted during two lunar days of operation. At the Surveyor 7 site, the cumulative size-frequency distribution of craters 13 cm to 3 meters in diameter follows closely the distribution of craters observed at the other Surveyor sites in the lunar maria. This distribution of small craters is believed to be a steady-state distribution.

Journal of Geophysical Research↗
USGS2013

The Borderlands and climate change: Chapter 10 in United States-Mexican Borderlands: Facing tomorrow's challenges through USGS science

The prediction of global climate change in response to both natural forces and human activity is one of the defining issues of our times. The unprecedented observational capacity of modern earth-orbiting satellites coupled with the development of robust computational representations (models) of the Earth’s weather and climate systems afford us the opportunity to observe and investigate how these systems work now, how they have worked in the past, and how they will work in the future when forced in specific ways. In the most recent report on global climate change by the Intergovernmental Panel on Climate Change (IPCC; Solomon and others, 2007), analyses using multiple climate models support recent observations that the Earth’s climate is changing in response to a combination of natural and human-induced causes. These changes will be significant in the United States–Mexican border region, where the process of climate change affects all of the Borderlands challenge themes discussed in the preceding chapters. The dual possibilities of both significantly-changed climate and increasing variability in climate make it challenging to take full measure of the potential effects because the Borderlands already experience a high degree of interannual variability and climatological extremes.

United States-Mexico Borderlands↗
USGS2002

35 - Strength and energetics of active fault zones

The strength of active fault zones, i.e., the shear stress level required to cause fault slip, is fundamental to understanding the physics of earthquakes and to assessing earthquake hazard. Although many researchers have concluded that fault zones are weak (shear stresses 10 MPa or less averaged between 0 and ˜20 km depth), others maintain that faults are strong (˜100 MPa average of an approximate linear increase with depth). Thus, despite 30 y of dedicated research, relevant data remain inconclusive and fault strength remains uncertain by an order of magnitude. In part, this is because the main source of energy release in earthquakes is at depths greater than 5 km, inaccessible to direct instrumental observation. Very large earthquakes rupture to the Earth's surface where direct observation of the shallow rupture process is possible. However, the rupture characteristics at shallow depth may differ from those at seismogenic depths. To date no great ( M ≥ 7.75) earthquakes have occurred within a network of modern strong-motion instruments, but the large, well-recorded 1999 earthquakes in Turkey and Taiwan, both M = 7.6, show that this data gap is rapidly being filled. Furthermore, shear stress changes at the earthquake source (and the resulting seismic waves) are nearly linear perturbations of the absolute stress field. Thus, an unknown absolute background stress does not greatly affect the basic characteristics of the observed low frequency seismic waves and the observed geodetic deformation. Other, less-direct data must then be used to infer the physical state and ambient stress levels on active faults. This chapter discusses available evidence and current ideas about fault zone strength and energetics. In our review we begin by outlining the general physical conditions prevailing in the Earth around active faults and summarize the generally agreed upon observational features of faulting and earthquake occurrence ( Section 2 ). In doing so we make as few assumptions as possible, because making uncertain assumptions may lead to logical inconsistencies and apparent paradoxes. For example, the absence of a measurable, frictionally generated heat flow anomaly near active faults, the so-called stress-heat flow paradox, rests upon assumptions that must somehow be incorrect. We wish to avoid such inconsistencies and to begin we introduce the observations and briefly state what they imply about fault zones. Subsequently, in Sections 3–8 , we place these observations in an interpretative context and show how they have been used to infer various measures of fault shear stress. Section 9 summarizes our assessment of the average shear stress state near faults, argues for the general importance of stress heterogeneity in faulting processes, and discusses its implications.

International Geophysics↗
USGS2011

Developing climate data records and essential climate variables from landsat data

The series of Landsat missions has compiled the longest record of satellite observation of the Earth’s land surface, extending for more than 38 years for most areas of the globe. Landsat data are particularly important as long term climate data records because the scale of observation is sufficient to differentiate between natural and human drivers of land cover change. The USGS has established consistent radiometric calibration across the Landsat TM and ETM+ sensors, and have extended the calibration back to the earlier MSS sensors. The USGS is developing capabilities to create fundamental climate data records (FCDRs), thematic climate data records (TCDRs), and essential climate variables (ECVs) from the Landsat data archive. Two high priority TCDRs were identified: surface reflectance and land surface temperature because they have direct application or are required as input to the generation of ECVs. We will focus development on a few of the terrestrial ECVs that have a high potential for being derived from Landsat data, that include land cover, albedo, fire disturbance, surface water, snow and ice, and leaf area index (LAI). We are collaborating with scientists who have demonstrated successful algorithm development and application of these science products to develop a framework of processing capabilities to support research projects and land management applications, along with an independent strategy for product validation. Our goal is to scale the creation and validation of these products from specific sites in the conterminous U.S. and Alaska, for extension to continental and global scales.

Conference Paper↗
USGS2023

Calibration and validation for the Surface Biology and Geology (SBG) mission concept: Recommendations for a multi-sensor system for imaging spectroscopy and thermal imagery

The primary objective of the National Aeronautics and Space Administration (NASA) Surface Biology and Geology (SBG) mission is to measure biological, physical, chemical, and mineralogical features of the Earth's surface, realizing a key conceptual component of the envisioned NASA Earth System Observatory (ESO). SBG is planned to launch as a two-platform mission in the late 2020s, the first of the ESO satellites. Targeted science and applications objectives based on observations of the Earth's SBG helped to define the mission architecture and instrument capabilities for the SBG mission concept. These objectives further drove the need for enabling change detection and trending of surface biological and geological features. These needs implied fundamental calibration goals to achieve the necessary science data quality characteristics. To meet those goals, calibration and validation pre-launch and on-orbit methods formed a basis of the calibration and validation concept, including the combined use of on-board references, vicarious techniques, and routine lunar imaging. International collaboration with space agencies in other countries, an important feature of the recommended SBG mission architecture, uncovered and emphasized the need for inter-calibration techniques that underscored the importance of collaborative instrument characterization data sharing and the use of common calibration references that are International System of Units (SI) traceable in pre-launch and post-launch on orbit calibration mission phases. International collaboration through the use of terrestrial and aquatic networks on six continents for vicarious calibration and validation activities will further assure necessary science data quality while in orbit.

JGR Biogeosciences↗
USGS1972

Photogeology: Part W: Apollo 16 landing site: summary of Earth-based remote sensing data

The purpose of the infrared (IR) and radar study of the Apollo data is to establish lunar surface conditions in the vicinity of the orbital tracks of the Apollo command modules during the J-series missions. Correlations and comparisons between the Earth-based radar observations, IR observations, and other data will be plotted on photomaps produced from the mapping and panoramic cameras. In addition, the Apollo photography will be used to improve the classifications of the anomalous IR and radar features. The three sets of Earth-based data have already been obtained. The IR (11 μm) data (ref. 29-112) were obtained during a total lunar eclipse. More than a thousand thermally anomalous regions with an unusually high population of exposed boulders have been identified (ref. 29-113). The 70-cm radar backscatter observations made at the same resolution as the IR measurements show regions of anomalous backscatter. These regions have been explained as roughness caused by the boulders on the surface and below the surface. The high-resolution 3.8-cm radar backscatter measurements (ref. 29-114) reveal in great detail regions of anomalous radar backscatter. At this short radar wavelength, small-scale surface and subsurface roughness and boulders less than the order of 10 cm are responsible for the anomalous returns. Previous studies have revealed strong correlation between these three data sets (refs. 29-115 to 29-117). The strongest anomalies (anomalous at all three wavelengths) correspond to features interpreted geologically as young Copernican craters. There are, however, many combinations of enhancements from IR only, 70-cm radar only, 3.8-cm radar only, or combinations of two of these types but not a third. The variation of intensity in all combinations indicates a very complex set of features. These data provide information about the surface on a centimeter- and meter-sized scale although the basic instrumental resolution was 2 to 15 km. The Apollo orbital photography and observations at the landing sites, used in conjunction with the remote sensing data, can significantly improve geologic and geophysical interpretations of lunar surface conditions.

Book chapter↗
USGS2022

The global seismographic network reveals atmospherically coupled normal modes excited by the 2022 Hunga Tonga eruption

The eruption of the submarine Hunga Tonga-Hunga Haʻapai (Hunga Tonga) volcano on 15 January 2022, was one of the largest volcanic explosions recorded by modern geophysical instrumentation. The eruption was notable for the broad range of atmospheric wave phenomena it generated and for their unusual coupling with the oceans and solid Earth. The event was recorded worldwide across the Global Seismographic Network (GSN) by seismometers, microbarographs and infrasound sensors. The broad-band instrumentation in the GSN allows us to make high fidelity observations of spheroidal solid Earth normal modes from this event at frequencies near 3.7 and 4.4 mHz. Similar normal mode excitations were reported following the 1991 Pinatubo (Volcanic Explosivity Index of 6) eruption and were predicted, by theory, to arise from the excitation of mesosphere-scale acoustic modes of the atmosphere coupling with the solid Earth. Here, we compare observations for the Hunga Tonga and Pinatubo eruptions and find that both strongly excited the solid Earth normal mode 0 S 29 (3.72 mHz). However, the mean modal amplitude was roughly 11 times larger for the 2022 Hunga Tonga eruption. Estimates of attenuation ( Q ) for 0 S 29 across the GSN from temporal modal decay give Q = 332 ± 101, which is higher than estimates of Q for this mode using earthquake data ( Q = 186.9 ± 5). Two microbarographs located at regional distances (<1000 km) to the volcano provide direct observations of the fundamental acoustic mode of the atmosphere. These pressure oscillations, first observed approximately 40 min after the onset of the eruption, are in phase with the seismic Rayleigh wave excitation and are recorded only by microbarographs in proximity (<1500 km) to the eruption. We infer that excitation of fundamental atmospheric modes occurs within a limited area close to the site of the eruption, where they excite select solid Earth fundamental spheroidal modes of similar frequencies that are globally recorded and have a higher apparent Q due to the extended duration of atmospheric oscillations.

Geophysical Journal International↗
USGS2013

Radiometric and geometric assessment of data from the RapidEye constellation of satellites

To monitor land surface processes over a wide range of temporal and spatial scales, it is critical to have coordinated observations of the Earth's surface using imagery acquired from multiple spaceborne imaging sensors. The RapidEye (RE) satellite constellation acquires high-resolution satellite images covering the entire globe within a very short period of time by sensors identical in construction and cross-calibrated to each other. To evaluate the RE high-resolution Multi-spectral Imager (MSI) sensor capabilities, a cross-comparison between the RE constellation of sensors was performed first using image statistics based on large common areas observed over pseudo-invariant calibration sites (PICS) by the sensors and, second, by comparing the on-orbit radiometric calibration temporal trending over a large number of calibration sites. For any spectral band, the individual responses measured by the five satellites of the RE constellation were found to differ <2–3% from the average constellation response depending on the method used for evaluation. Geometric assessment was also performed to study the positional accuracy and relative band-to-band (B2B) alignment of the image data sets. The position accuracy was assessed by comparing the RE imagery against high-resolution aerial imagery, while the B2B characterization was performed by registering each band against every other band to ensure that the proper band alignment is provided for an image product. The B2B results indicate that the internal alignments of these five RE bands are in agreement, with bands typically registered to within 0.25 pixels of each other or better.

International Journal of Remote Sensing↗
USGS1981

United States Geological Survey Yearbook, fiscal year 1980

It is not very often that a single event is so overwhelming that it changes public perceptions of natural hazards for generations. Perhaps for the U.S. Geological Survey, the explosive volcanic activity of Mount St. Helens began such a change. After 101 years of careful science of the Earth's past and meticulous observations and assessments of the present, predictive earth science was in full public view. However vague and faint the glimpse of the future made possible by earth science, it was enough. Warnings were issued, thousands of lives were saved, and the age of real-time geology began. The Survey's basic mission has not changed, but the power of our analytical tools has increased by several orders of magnitude. The Survey's efforts to understand Earth processes and hydrologic principles continued with the collection, during fiscal year 1980, of valuable new data on the geologic origin and framework, seismicity, and mineral and energy resources of the United States. The Survey is also responsible for classification of the leasable minerals on Federal lands and the regulation of mineral exploration and development activities on Federal and Indian lands. As the principal earth science fact-gathering agency, the Survey provides information for sound decisionmaking by government and private industry. Industry uses the Survey's information in exploring for energy and minerals and improving their efforts to make development of energy and minerals compatible with environmental protection standards. Government uses the Survey's information in conducting leasing operations on public lands, in regulating the safe design and siting of nuclear plants, and in establishing guidelines for determining and locating areas that are subject to geologic hazards such as landslides, earthquakes, and volcanic eruptions. The Yearbook reports a broad range of the Survey's accomplishments during the past fiscal year and provides an overview of future directions. Many of the topics covered will continue to be important natural resource and earth science issues of the 1980's.

Yearbook↗
USGS1977

The Aristarchus-Harbinger region of the moon: Surface geology and history from recent remote-sensing observations

The region including the Aristarchus Plateau and Montes Harbinger is probably the most diverse, geologically, of any area of comparble size on the Moon. This part of the northwest quadrant of the lunar near side includes unique dark mantling material; both the densest concentration and the largest of the sinuous rilles; apparent volcanic vents, sinks, and domes; mare materials of various ages and colors; one of the freshest large craters (Aristarchus) with ejecta having unique colors and albedos; and three other large craters in different states of flooding and degradation (krieger, Herodotus, and Prinz). The three best-authenticated lunar transient phenomena were also observed here. This study is based principally on photographic and remote sensing observations made from Earth and Apollo orbiting space craft. Results include (1) delineation of geologic map units and their stratigraphic relationships; (2) discussion of the complex interrelationships between materials of volcanic and impact origin, including the effects of excavation, redistribution and mixing of previously deposited materials by younger impact craters; (3) deduction of physical and chemical properties of certain of the geologic units, based on both the remote-sensing information and on extrapolation of Apollo data to this area; and (4) development of a detailed geologic history of the region, outlining the probable sequence of events that resulted in its present appearance. A primary concern of the investigation has been anomalous red dark mantle on the Plateau. Based on an integration of Earth- and lunar orbit-based data, this layer seems to consist of fine-grained, block-free material containing a relatively large fraction of orange glass. It is probably of pyroclastic origin, laid down at some time during the Imbrian period of mare flooding. ?? 1977 D. Reidel Publishing Company.

The Moon↗