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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.

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At least 757 records · Page 42Linked to original sources
USGS2022

First principles calibration of 40Ar abundances in 40Ar/39Ar mineral neutron fluence monitors: Methodology and preliminary results

The accuracy and traceability of geochronometers are of vital importance to questions asked by many Earth scientists. The widely applied 40 Ar/ 39 Ar geochronometer relies on the co-irradiation of samples with neutron fluence monitors (reference materials) of known ages; the ages and uncertainties of these monitors are critical to our ability to apply this chronometer. Previously, first principles, astronomical and optimisation calibrations have been made. The first principles method for determining the age of monitor minerals is the K-Ar method, which involves measurement of their 40 K and 40 Ar* abundances. The AQuA (Absolute Quantities of Argon) pipette system, which emits calibrated quantities of 40 Ar* via the ideal gas law, was used to calibrate the sensitivity of the system across a range of source pressures and estimate 40 Ar* abundances in neutron fluence monitors. These 40 Ar abundances were combined with existing 40 K abundance data for these monitors. Ages for HD-B1 and MD2 (GA1550) biotite fluence monitors were calculated and combined with intercalibration data for HD-B1 and Fish Canyon sanidine (FCs) to determine ages for FCs. Current results do not have the targeted accuracy when compared with previous calibrations; however, we show how the extensive methodology development presented here can be used towards making reliable future measurements.

Geostandards and Geoanalytical Research↗
USGS2014

Volcanology: Lessons learned from Synthetic Aperture Radar imagery

Twenty years of continuous Earth observation by satellite SAR have resulted in numerous new insights into active volcanism, including a better understanding of subsurface magma storage and transport, deposition of volcanic materials on the surface, and the structure and development of volcanic edifices. This massive archive of data has resulted in fundamental leaps in our understanding of how volcanoes work – for example, identifying magma accumulation at supposedly quiescent volcanoes, even in remote areas or in the absence of ground-based data. In addition, global compilations of volcanic activity facilitate comparison of deformation behavior between different volcanic arcs and statistical evaluation of the strong link between deformation and eruption. SAR data are also increasingly used in timely hazard evaluation thanks to decreases in data latency and growth in processing and analysis techniques. The existing archive of SAR imagery is on the cusp of being enhanced by a new generation of satellite SAR missions, in addition to ground-based and airborne SAR systems, which will provide enhanced temporal and spatial resolution, broader geographic coverage, and improved availability of data to the scientific community. Now is therefore an opportune time to review the contributions of SAR imagery to volcano science, monitoring, and hazard mitigation, and to explore the future potential for SAR in volcanology. Provided that the ever-growing volume of SAR data can be managed effectively, we expect the future application of SAR data to expand from being a research tool for analyzing volcanic activity after the fact, to being a monitoring and research tool capable of imaging a wide variety of processes on different temporal and spatial scales as those processes are occurring. These data can then be used to develop new models of how volcanoes work and to improve quantitative forecasts of volcanic activity as a means of mitigating risk from future eruptions.

Journal of Volcanology and Geothermal Research↗
USGS2014

Landsat-8: Science and product vision for terrestrial global change research

Landsat 8, a NASA and USGS collaboration, acquires global moderate-resolution measurements of the Earth's terrestrial and polar regions in the visible, near-infrared, short wave, and thermal infrared. Landsat 8 extends the remarkable 40 year Landsat record and has enhanced capabilities including new spectral bands in the blue and cirrus cloud-detection portion of the spectrum, two thermal bands, improved sensor signal-to-noise performance and associated improvements in radiometric resolution, and an improved duty cycle that allows collection of a significantly greater number of images per day. This paper introduces the current (2012–2017) Landsat Science Team's efforts to establish an initial understanding of Landsat 8 capabilities and the steps ahead in support of priorities identified by the team. Preliminary evaluation of Landsat 8 capabilities and identification of new science and applications opportunities are described with respect to calibration and radiometric characterization; surface reflectance; surface albedo; surface temperature, evapotranspiration and drought; agriculture; land cover, condition, disturbance and change; fresh and coastal water; and snow and ice. Insights into the development of derived ‘higher-level’ Landsat products are provided in recognition of the growing need for consistently processed, moderate spatial resolution, large area, long-term terrestrial data records for resource management and for climate and global change studies. The paper concludes with future prospects, emphasizing the opportunities for land imaging constellations by combining Landsat data with data collected from other international sensing systems, and consideration of successor Landsat mission requirements.

Remote Sensing of Environment↗
USGS2014

Baseline coastal oblique aerial photographs collected from Breton Island, Louisiana, to the Alabama-Florida border, July 13, 2013

The U.S. Geological Survey (USGS) conducts baseline and storm response photography missions to document and understand the changes in vulnerability of the Nation's coasts to extreme storms. On July 13, 2013, the USGS conducted an oblique aerial photographic survey from Breton Island, Louisiana, to the Alabama-Florida border, aboard a Cessna 172 flying at an altitude of 500 feet (ft) and approximately 1,000 ft offshore. This mission was flown to collect baseline data for assessing incremental changes since the last survey, and the data can be used in the assessment of future coastal change. The images provided here are Joint Photographic Experts Group (JPEG) images. ExifTtool was used to add the following to the header of each photo: time of collection, Global Positioning System (GPS) latitude, GPS longitude, keywords, credit, artist (photographer), caption, copyright, and contact information. The photograph locations are an estimate of the position of the aircraft and do not indicate the location of any feature in the images (see the Navigation Data page). These photographs document the configuration of the barrier islands and other coastal features at the time of the survey. Pages containing thumbnail images of the photographs, referred to as contact sheets, were created in 5-minute segments of flight time. These segements can be found on the Photos and Maps page. Photographs can be opened directly with any JPEG-compatible image viewer by clicking on a thumbnail on the contact sheet. Table 1 provides detailed information about the GPS location, name, date, and time each of the 1242 photographs taken along with links to each photograph. The photography is organized into segments, also referred to as contact sheets, and represent approximately 5 minutes of flight time. (Also see the Photos and Maps page). In addition to the photographs, a Google Earth Keyhole Markup Language (KML) file is provided and can be used to view the images by clicking on the marker and then clicking on either the thumbnail or the link above the thumbnail. The KML files were created using the photographic navigation files.

Alabama;Florida;Louisiana;Mississippi↗
USGS2014

Baseline coastal oblique aerial photographs collected from Dauphin Island, Alabama, to Breton Island, Louisiana, August 8, 2012

The U.S. Geological Survey (USGS) conducts baseline and storm response photography missions to document and understand the changes in vulnerability of the Nation's coasts to extreme storms. On August 8, 2012, the USGS conducted an oblique aerial photographic survey from Dauphin Island, Alabama, to Breton Island, Louisiana, aboard a Cessna 172 at an altitude of 500 feet (ft) and approximately 1,000 ft offshore. This mission was flown to collect baseline data for assessing incremental changes since the last survey, and the data can be used in the assessment of future coastal change. The images provided here are Joint Photographic Experts Group (JPEG) images. Exiftool was used to add the following to the header of each photo: time of collection, Global Positioning System (GPS) latitude, GPS longitude, keywords, credit, artist (photographer), caption, copyright, and contact information. The photograph locations are an estimate of the position of the aircraft and do not indicate the location of any feature in the images (see the Navigation Data page). These photographs document the configuration of the barrier islands and other coastal features at the time of the survey. Pages containing thumbnail images of the photographs, referred to as contact sheets, were created in 5-minute segments of flight time. These segements can be found on the Photos and Maps page. Photographs can be opened directly with any JPEG-compatible image viewer by clicking on a thumbnail on the contact sheet. Table 1 provides detailed information about the GPS location, name, date, and time each of the 1241 photographs taken along with links to each photograph. The photography is organized into segments, also referred to as contact sheets, and represent approximately 5 minutes of flight time. (Also see the Photos and Maps page). In addition to the photographs, a Google Earth Keyhole Markup Language (KML) file is provided and can be used to view the images by clicking on the marker and then clicking on either the thumbnail or the link above the thumbnail. The KML files were created using the photographic navigation files.

Alabama;Louisiana↗
USGS1977

Reconnaissance engineering geology of the Metlakatla area, Annette Island, Alaska, with emphasis on evaluation of earthquakes and other geologic hazards

A program to study the engineering geology of most larger Alaska coastal communities and to evaluate their earthquake and other geologic hazards was started following the 1964 Alaska earthquake; this report about the Metlakatla area, Annette Island, is a product of that program. Field-study methods were of a reconnaissance nature, and thus the interpretations in the report are tentative. Landscape of the Metlakatla Peninsula, on which the city of Metlakatla is located, is characterized by a muskeg-covered terrane of very low relief. In contrast, most of the rest of Annette Island is composed of mountainous terrane with steep valleys and numerous lakes. During the Pleistocene Epoch the Metlakatla area was presumably covered by ice several times; glaciers smoothed the present Metlakatla Peninsula and deeply eroded valleys on the rest. of Annette Island. The last major deglaciation was completed probably before 10,000 years ago. Rebound of the earth's crust, believed to be related to glacial melting, has caused land emergence at Metlakatla of at least 50 ft (15 m) and probably more than 200 ft (61 m) relative to present sea level. Bedrock in the Metlakatla area is composed chiefly of hard metamorphic rocks: greenschist and greenstone with minor hornfels and schist. Strike and dip of beds are generally variable and minor offsets are common. Bedrock is of late Paleozoic to early Mesozoic age. Six types of surficial geologic materials of Quaternary age were recognized: firm diamicton, emerged shore, modern shore and delta, and alluvial deposits, very soft muskeg and other organic deposits, and firm to soft artificial fill. A combination map unit is composed of bedrock or diamicton. Geologic structure in southeastern Alaska is complex because, since at least early Paleozoic time, there have been several cycles of tectonic deformation that affected different parts of the region. Southeastern Alaska is transected by numerous faults and possible faults that attest to major movements of the earth's crust. The latest of the major tectonic events in the Metlakatla region occurred in middle Tertiary time; some minor fault activity probably continues today at depth. Along the outer coast of southeastern Alaska and British Columbia, major faulting activity occurs in the form of active, strike-slip movement along the Queen Charlotte fault about 100 mi (160 kin) west-southwest of Metlakatla. Some branching subsidiary faults also may be active, at least one of which may be the Sandspit fault. Many major and smaller earthquakes occur along the outer coast. These shocks are related to movements along the Queen Charlotte fault. A few small earthquakes occur in the region between the outer coast and the Coast Mountains, which includes Metlakatla. 0nly a few earthquakes have been reported as felt at Metlakatla; these shocks and others felt in the region are tabulated. Historically, the closest major earthquake was the magnitude 8.1 Queen Charlotte Islands earthquake of August 22, 1949, which occurred along the Queen Charlotte fault 125 mi (200 km) southwest of Metlakatla. No damage was reported at Metlakatla. The probability of destructive earthquakes affecting Metlakatla is unknown. A consideration of the tectonics and earthquake history of the region, however, suggests that sometime in the future an earthquake with a magnitude of about 8 will occur along that segment of the Queen Charlotte fault nearest to Metlakatla. Smaller earthquakes with magnitudes of 6 or more might occur elsewhere in the Metlakatla region or south-southeastward near Dixon Entrance or Hecate Strait. Several geologic effects that have characterized large earthquakes elsewh6re may be expected to accompany some of the possible major earthquakes that might affect the Metlakatla area in the future. Evaluation of effects indicates that fault displacement and tectonic uplift or subsidence are probably unlikely, and ground shaking in general probably would be strongest

Open-File Report↗
USGS1996

USGS response to an urban earthquake, Northridge '94

The urban centers of our Nation provide our people with seemingly unlimited employment, social, and cultural opportunities as a result of the complex interactions of a diverse population embedded in an highly-engineered environment. Catastrophic events in one or more of the natural earth systems which underlie or envelop urban environment can have radical effects on the integrity and survivability of that environment. Earthquakes have for centuries been the source of cataclysmic events on cities throughout the world. Unlike many other earth processes, the effects of major earthquakes transcend all political, social, and geomorphic boundaries and can have decided impact on cities tens to hundreds of kilometers from the epicenter. In modern cities, where buildings, transportation corridors, and lifelines are complexly interrelated, the life, economic, and social vulnerabilities in the face of a major earthquake can be particularly acute. The 1994 Northridge Earthquake was a major test for parts of what many consider the most earthquake-prepared and best-engineered metropolitan region in the United States. While the combined efforts of concerned professionals at all levels of government, academia, and the private sector have produced significant advances in our knowledge of the causes and potential effects of earthquakes, and of ways to reduce their impact, it remains unfortunately true that actual earthquakes provide important opportunities to test those advances in our knowledge. In the hours and days following the Northridge Earthquake, the four Federal member agencies of the National Earthquake Hazards Reduction Program (NEHRP), the Federal Emergency Management Agency (FEMA), the National Institute for Standards and Technology (NIST), the National Science Foundation (NSF), and the United States Geological Survey (USGS) laid out a detailed plan for collecting, analyzing, archiving, and reporting information that would benefit the Nation in future earthquake hazards reduction efforts. Congress provided a special appropriation to FEMA to carry out this plan and FEMA distributed those funds to the four NEHRP agencies. The USGS was responsible for conducting geophysical and geological investigations in support of the NEHRP Post-earthquake Study. For the past 2 years, the USGS has rigorously pursued over 40 tasks focused on the USGS Northridge Earthquake Mission. This document is a summary report of the USGS findings; additional technical reports on specific USGS tasks are appearing in various scientific journals and USGS publications.

California↗
USGS2017

U.S. Geological Survey Karst Interest Group Proceedings, San Antonio, Texas, May 16–18, 2017

Introduction and Acknowledgments Karst aquifer systems are present throughout parts of the United States and some of its territories, and have developed in carbonate rocks (primarily limestone and dolomite) and evaporites (gypsum, anhydrite, and halite) that span an interval of time encompassing more than 550 million years. The depositional environments, diagenetic processes, post-depositional tectonic events, and geochemical weathering processes that form karst aquifers are varied and complex. These factors involve biological, chemical, and physical changes that when combined with the diverse climatic regimes in which karst development has taken place, result in the unique dual- or triple-porosity nature of karst aquifers. These complex hydrogeologic systems typically represent challenging and unique conditions to scientists attempting to study groundwater flow and contaminant transport in these terrains. The dissolution of carbonate rocks and the subsequent development of distinct and beautiful landscapes, caverns, and springs have resulted in the most exceptional karst areas being designated as national or state parks. Tens of thousands of similar areas in the United States have been developed into commercial caverns and known privately owned caves. Both public and private properties provide access for scientists to study the flow of groundwater in situ . Likewise, the range and complexity of landforms and groundwater flow systems associated with karst terrains are enormous, perhaps more than for any other aquifer type. Karst aquifers and landscapes that form in tropical areas, such as the cockpit karst along the north coast of Puerto Rico, differ greatly from karst landforms in more arid climates, such as the Edwards Plateau in west-central Texas or the Guadalupe Mountains near Carlsbad, New Mexico, where hypogenic processes have played a major role in speleogenesis. Many of these public and private lands also contain unique flora and fauna associated with these karst hydrogeologic systems. As a result, numerous federal, state, and local agencies have a strong interest in the study of karst terrains. Many of the major springs and aquifers in the United States have developed in carbonate rocks, such as the Floridan aquifer system in Florida and parts of Alabama, Georgia, and South Carolina; the Ozark Plateaus aquifer system in parts of Arkansas, Kansas, Missouri, and Oklahoma; and the Edwards-Trinity aquifer system in west-central Texas. These aquifers, and the springs that discharge from them, serve as major water-supply sources and form unique ecological habitats. Competition for the water resources of karst aquifers is common, and urban development and the lack of attenuation of contaminants in karst areas due to dissolution features that form direct pathways into karst aquifers can impact the ecosystem and water quality associated with these aquifers. The concept for developing a platform for interaction among scientists within the U.S. Geological Survey (USGS) working on karst-related studies evolved from the November 1999 National Groundwater Meeting of the USGS. As a result, the Karst Interest Group (KIG) was formed in 2000. The KIG is a loose-knit, grass-roots organization of USGS and non-USGS scientists and researchers devoted to fostering better communication among scientists working on, or interested in, karst science. The primary mission of the KIG is to encourage and support interdisciplinary collaboration and technology transfer among scientists working in karst areas. Additionally, the KIG encourages collaborative studies between the different mission areas of the USGS as well as with other federal and state agencies, and with researchers from academia and institutes. To accomplish its mission, the KIG has organized a series of workshops that have been held near nationally important karst areas. To date (2017) seven KIG workshops, including the workshop documented in this report, have been held. The workshops typically include oral and poster sessions on selected karst-related topics and research, as well as field trips to local karst areas. To increase non-USGS participation an effort was made for the workshops to be held at a university or institute beginning with the fourth workshop. Proceedings of the workshops are published by the USGS and are available online at the USGS publications warehouse https://pubs.er.usgs.gov/ by using the search term “karst interest group.” The first KIG workshop was held in St. Petersburg, Florida, in 2001, in the vicinity of the large springs and other karst features of the Floridan aquifer system. The second KIG workshop was held in 2002, in Shepherdstown, West Virginia, in proximity to the carbonate aquifers of the northern Shenandoah Valley, and highlighted an invited presentation on karst literature by the late Barry F. Beck of P.E. LaMoreaux and Associates. The third KIG workshop was held in 2005, in Rapid City, South Dakota, near evaporite karst features in limestones of the Madison Group in the Black Hills of South Dakota. The Rapid City KIG workshop included field trips to Wind Cave National Park and Jewel Cave National Monument, and featured a presentation by Thomas Casadevall, then USGS Central Region Director, on the status of Earth science at the USGS. The fourth KIG workshop in 2008 was hosted by the Hoffman Environmental Research Institute and Center for Cave and Karst Studies at Western Kentucky University in Bowling Green, Kentucky, near Mammoth Cave National Park and karst features of the Chester Upland and Pennyroyal Plateau. The workshop featured a late-night field trip into Mammoth Cave led by Rickard Toomey and Rick Olsen, National Park Service. The fifth KIG workshop in 2011 was a joint meeting of the USGS KIG and University of Arkansas HydroDays, hosted by the Department of Geosciences at the University of Arkansas in Fayetteville. The workshop featured an outstanding field trip to the unique karst terrain along the Buffalo National River in the southern Ozarks, and a keynote presentation on paleokarst in the United States was delivered by Art and Peggy Palmer. The sixth KIG workshop was hosted by the National Cave and Karst Research Institute (NCKRI) in 2014, in Carlsbad, New Mexico. George Veni, Director of the NCKRI, served as a co-chair of the workshop with Eve Kuniansky of the USGS. The workshop featured speaker Dr. Penelope Boston, Director of Cave and Karst Studies at New Mexico Tech, Socorro, and Academic Director at the NCKRI, who addressed the future of karst research. The field trip on evaporite karst of the lower Pecos Valley was led by Lewis Land (NCKRI karst hydrologist), and the field trip on the geology of Carlsbad Caverns National Park was led by George Veni. This current seventh KIG workshop is being held in San Antonio at the University of Texas at San Antonio (UTSA). This 2017 workshop is being hosted by the Department of Geological Sciences’ Student Geological Society (SGS), and student chapters of the American Association of Petroleum Geologists (AAPG) and Association of Engineering Geologists (AEG), with support by the UTSA Department of Geological Sciences and Center for Water Research. The UTSA student chapter presidents, Jose Silvestre (SGS), John Cooper (AAPG), and Tyler Mead (AEG) serve as co-chairs of the 2017 workshop with Eve Kuniansky of the USGS. The technical session committee is chaired by Eve Kuniansky, USGS, and includes Michael Bradley, Tom Byl, Rebecca Lambert, John Lane, and James Kaufmann, all USGS, and Patrick Tucci, retired USGS. The logistics committee includes Amy Clark, Yongli Gao, and Lance Lambert (Department Chair), UTSA Department of Geological Sciences; and Ryan Banta and Allan Clark, USGS, San Antonio, Texas. The field trip committee is chaired by Allan Clark and includes Amy Clark, Yongli Gao, and Keith Muehlestein, UTSA; Marcus Gary, Edwards Aquifer Authority and University of Texas at Austin; Ron Green, Southwest Research Institute; Geary Schindel, Edwards Aquifer Authority; and George Veni, NCKRI. Additionally, two organizations have assisted the UTSA student chapters in hosting the meeting by donating funds to the chapters: the Edwards Aquifer Authority, San Antonio, Texas, and the Barton Springs Edwards Aquifer Authority, Austin, Texas. Additionally, Yongli Gao, Center for Water Research and Department of Geological Sciences, UTSA, helped develop sessions on cave and karst research in China for this workshop. These proceedings could not have been accomplished without the assistance of Lawrence E. Spangler as co-editor who not only has subject matter expertise, but also serves as an editor with the USGS Science Publishing Network. We sincerely hope that this workshop continues to promote future collaboration among scientists of varied and diverse backgrounds, and improves our understanding of karst aquifer systems in the United States and its territories. The extended abstracts of USGS authors were peer reviewed and approved for publication by the USGS. Articles submitted by university researchers and other federal and state agencies did not go through the formal USGS peer review and approval process, and therefore may not adhere to USGS editorial standards or stratigraphic nomenclature. However, all articles had a minimum of two peer reviews and were edited for consistency of appearance in the proceedings. The use of trade, firm or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. The USGS Water Availability and Use Science Program funded the publication costs of the proceedings.

Scientific Investigations Report↗
USGS2026

Future water constraints on United States lithium mining under climate change

Lithium is necessary for low-carbon technologies that combat climate change, but lithium extraction is water-intensive. Changes in temperature and precipitation arising from climate change are altering water distribution, which could further strain supplies for new mines and industry, farms, and households. Here we explored how climate change, water use, and mining siting could impact lithium mining in the United States. We analyzed whether there would be sufficient water available to support the single existing and 22 proposed U.S. lithium mines at mid-century under four socioeconomic-climate scenarios and five climate models. Though dependent on socioeconomic-climate scenario, climate model, and lithium deposit type, available water supply in most subbasins would likely be unable to support new mines’ water demands, or even non-mining water demands from other sectors. Water scarcity could hinder the ability of the United States to produce enough lithium to meet domestic demand thereby necessitating higher imports.

conterminous United States↗
USGS1988

Measuring contemporary crustal motions; NASA’s Crustal Dynamics Project

In the early and middle 1970's, two new space-based geodetic techniques became available that offered unprecedented accuracy in the measurement of distances over long baselines. As described below, Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI) provided a capability to determine in relatively short periods of time the inter-site distance between two observing stations to a level of several centimeters, even if they were separated by thousands or tens of thousands of kilometers. During the 1980's the two techniques have evolved to the point where baselines can now be routinely measured to a level below one centimeter. This is a tenfold improvement in about ten years. Perhaps more important than providing the measurement capability are the consequences of this capability when applied over a few years: the motion of any one site with respect to another can be monitored at the level of better than a cm/yr. This has made possible, for the first time, direct measurement of the motion of the Earth's tectonic plates and of the deformation of its crust in active plate boundary regions. Because such measurements have the potential for providing important information on the mechanisms that drive plates and cause them to slip during earthquakes, a coordinated federal program for the application of this space technology to crustal dynamics and earthquake research was established in 1979. The participating agencies were the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration (NOAA), the United States Geological Survey (USGS), the National Science Foundation (NSF), and the Defense Mapping Agency. NASA formed the Crustal Dynamics Project to further develop the SLR and VLBI techniques, to implement global networks of stations with the cooperation of many different countries, and to conduct measurements of plate motions and regional deformations. this project has grown into an international effort to collect information directly relevant to understanding the threat of the earthquake hazard as well as fundamental research about the crust and upper mantle. In this article we describe briefly the two space geodetic techniques and how they are used by the Crustal Dynamics Project, show some of the very exciting results that have emerged at the halfway point in the project's life, describe the availability and utilization of the data being collected, and consider what the future may hold when measurement accuracies eventually exceed even those now available and when other international groups become more heavily involved.

Earthquakes & Volcanoes (USGS)↗
USGS2026

On-demand global Landsat evapotranspiration product: Development, evaluation, and dissemination

Global actual evapotranspiration (ET) is one of the essential climate variables needed to understand and manage the relationships among food, energy, and water resources. The U.S. Geological Survey Earth Resources Observation and Science (EROS) Center launched a provisional ET product in 2020, offering on-demand, field-scale global coverage derived from Landsat data through the EROS Science Processing Architecture (ESPA) platform. The ESPA interface provides ET data for cloud-free Landsat overpasses starting in 1982 with Landsat 4 through the current Landsat 9. The ET data are delivered as a Provisional Level-3 Science product created using the Operational Simplified Surface Energy Balance (SSEBop) model. Landsat surface temperature and reference ET are the main model drivers along with vegetation index and net radiation for model parameterization. A large volume of Landsat-based ET orders (e.g., over 1,200,000 images from June 2020 through December 2025) around the world indicate increasing awareness and application of the ET data. The ESPA platform enables land and water resource managers and researchers to access a first-order ET product without requiring advanced knowledge of remote sensing technology or evapotranspiration modeling. We present the methodology and workflow of the on-demand Landsat ET product and its performance evaluations over diverse hydro-climatic settings. The product can help estimate field-scale consumptive water use and thus quickly and consistently assess historical water use, allocation, and budget to inform water management under changing environments. Future ET data aggregated to monthly and seasonal time scales are expected to enhance integration with decision-making tools and procedures.

Remote Sensing of Environment↗
USGS2010

Accuracy of EAARL lidar ground elevations using a bare-earth algorithm in marsh and beach grasses on the Chandeleur Islands, Louisiana

The NASA Experimental Advanced Airborne Lidar (EAARL) is an airborne lidar (light detection and ranging) instrument designed to map coastal topography and bathymetry. The EAARL system has the capability to capture each laser-pulse return over a large signal range and can digitize the full waveform of the backscattered energy. Because of this ability to capture the full waveform, the EAARL system can map features such as coral reefs, beaches, coastal vegetation, and trees, where extreme variations in the laser backscatter are caused by different physical and optical characteristics. Post-processing of the EAARL data is accomplished using the Airborne Lidar Processing System (ALPS) (Nayegandhi and others, 2009). In ALPS, the waveform of the lidar is analyzed and split into first and last returns. The 'first returns' are indicative of vegetation-canopy height, or bare ground in the absence of vegetation, whereas 'last returns' typically represent 'bare-earth' elevations under vegetation. To test the accuracy of the first-return and bare-earth EAARL data, topographic and vegetation height surveys were conducted in the Chandeleur Islands, concurrent with an EAARL lidar survey and an aerial oblique-photographic survey from September 20 to 27, 2006. The Chandeleur Islands are a north-south-oriented chain of low-lying islands located approximately 100 kilometers east of the city of New Orleans, Louisiana. The islands are narrow north-south strips of land with marsh on the landward (west sides) and sandy beaches on their gulfward (east sides). Prior to Hurricane Katrina, which made landfall at Buras, Louisiana, as a Category 3 storm on August 29, 2005, prominent, 3- to 4-meter-high sand dunes were present in the northern Chandeleurs. The storm removed them, leaving post-storm island elevations of generally less than 2 meters above 0.0 NAVD88. This report is part of a study of the impact of Hurricane Katrina on the Chandeleur Islands using pre-storm and post-storm lidar surveys to detect morphological changes. The islands lost over 80 percent of their land area during Hurricane Katrina, and in the first 2 years following Katrina, many of the islands experienced continued shoreline retreat (Sallenger and others, 2007). In addition to land-area losses, the loss of dunes made the islands increasingly vulnerable to future storm impacts. The U.S. Geological Survey, along with partners in the Louisiana Department of Natural Resources and the U.S. Army Corps of Engineers, continues to monitor changes in shoreline position, land area, and elevation in the Chandeleur Islands.

Open-File Report↗
USGS2024

Sea level rise threatens Florida’s insular vertebrate biodiversity

Islands are some of the most biodiverse places on earth, but they are also hotspots of biodiversity loss. The coastline of Florida, U.S.A., is surrounded by thousands of islands, many of which are home to species that occur nowhere else. A rapidly emerging threat to these low-lying islands is inundation as sea levels rise. The capacity of island-dwelling species to adapt to climate change and sea level rise may be limited because many species do not have the ability to shift their distribution off the island to track favorable conditions. We assessed the vulnerability of Florida’s islands to inundation from sea level rise and estimated the terrestrial biodiversity on Florida’s islands that could be lost. Our models predicted that by 2100, over 80% and up to 90% of Florida’s islands could be completely inundated from sea level rise, depending on the sea level rise projection (1.2 m or 2.2 m). Of the 85 mammalian, reptilian, and amphibian species on our subset list of Florida’s Species of Greatest Conservation Need, over half occur on Florida’s islands for at least part of their range, highlighting the importance of these islands for housing Florida’s rich biodiversity. Notably, at least 12 mammal species and 7 reptile species have their entire distribution on Florida’s islands, and this count is likely an underestimate. Projections of future sea level rise mean that these island-endemic species face the threat of extinction in the wild if their island habitat is submerged.

Florida↗
USGS2014

Using multiple data sets to populate probabilistic volcanic event trees

The key parameters one needs to forecast outcomes of volcanic unrest are hidden kilometers beneath the Earth’s surface, and volcanic systems are so complex that there will invariably be stochastic elements in the evolution of any unrest. Fortunately, there is sufficient regularity in behaviour that some, perhaps many, eruptions can be forecast with enough certainty for populations to be evacuated and kept safe. Volcanologists charged with forecasting eruptions must try to understand each volcanic system well enough that unrest can be interpreted in terms of pre-eruptive process, but must simultaneously recognize and convey uncertainties in their assessment. We have found that use of event trees helps to focus discussion, integrate data from multiple sources, reach consensus among scientists about both pre-eruptive process and uncertainties and, in some cases, to explain all of this to officials. Figure 1 shows a generic volcanic event tree from Newhall and Hoblitt (2002) that can be modified as needed for each specific volcano. This paper reviews how we and our colleagues have used such trees during a number of volcanic crises worldwide, for rapid hazard assessments in situations in which more formal expert elicitations could not be conducted. We describe how Multiple Data Sets can be used to estimate probabilities at each node and branch. We also present case histories of probability estimation during crises, how the estimates were used by public officials, and some suggestions for future improvements.

Book chapter↗
USGS2019

To what extent is drought-induced tree mortality a natural phenomenon?

Aim Catastrophic forest mortality due to more extreme rainfall deficits and higher temperatures under future climate scenarios has been predicted. The aim of this study is to explore the magnitude of historical drought-induced tree mortality under pre-warming conditions. Location North-eastern Australia. Time period 1845–2017. Major taxa studied Trees. Methods Field survey, historical analysis and climate analysis. Results We present evidence of 18%–30% tree mortality from recent droughts across three regions of north-eastern Australia with rainfall deficits less severe than earlier historical droughts. The corrected temperature record represents modest warming at the stations with long records in the vicinity of the study areas. In terms of rainfall deficit the most severe drought on record occurred in the early 20th century, and historical evidence confirms that this drought and earlier droughts before the advent of pastoralism coincided with substantial tree mortality. Main conclusions Dramatic declines in woody biomass in response to drought historically occurred more than once a century and are a natural phenomenon in semi-arid Australia. The magnitude of drought-induced tree mortality under natural climate fluctuations requires further investigation in other continents. Widespread drought-induced tree mortality is not just a recent global change phenomenon and has been underestimated as a natural ecological process. However, even more severe forest die-off events from more extreme hotter droughts are predicted if Earth’s warming proceeds as currently projected.

Queensland↗
USGS2021

Three-dimensional electrical resistivity characterization of Mountain Pass, California and surrounding region

The Sulphide Queen carbonatite deposit at Mountain Pass in southeast California is a world class rare earth element (REE) resource. This study images electrical resistivity structure of the REE deposit and surrounding area to characterize resources under cover. An east-west elongated grid (35 × 15 km) of 65 wideband magnetotelluric stations spanning from eastern Shadow Valley to eastern Ivanpah Valley were collected and modeled in three-dimensions (3-D). Gravity, aeromagnetic, and geologic data are used to inform interpretation of structures in the resistivity model, including the following observations. Shadow Valley is filled with conductive sediment that locally dips southward to a depth of 1 km. The Kingston Range-Halloran Hills detachment fault dips westward at ∼15 degrees. The REE deposit is a moderate low resistivity zone dipping southwest to a possible depth of ∼1 km, and is bounded by the North and South faults and bisected by the Middle fault. Ivanpah Dry Lake is underlain by a north striking southward dipping sedimentary basin. Two possible zones of mineralization are observed in Ivanpah Valley, one along the western edge of Ivanpah Dry Lake and one on the western edge of valley along a new inferred fault. The brittle-ductile transition is imaged at ∼10 km below mean sea level. No deep electrically conductive structures are imaged to be related to the REE deposit likely due to the complex geologic history of the Mojave terrane. Future studies should regional target Proterozoic rocks and search within for geophysical signatures similar to Mountain Pass.

California↗
USGS2007

Outcrop descriptions and fossils from the Upper Cretaceous Frontier Formation, Wind River Basin and adjacent areas, Wyoming: Chapter 11 in Petroleum systems and geologic assessment of oil and gas resources in the Wind River Basin Province, Wyoming

The Wind River Basin of central Wyoming trends west-northwest from near the community of Alcova to near the town of Dubois (fig. 1). On the perimeter of the basin, outcrops of the Frontier Formation were examined and described during the years 1972-1975. Invertebrate fossils were collected from those outcrops during the years 1972-1996, in places with the assistance of other earth scientists (see Acknowledgments). The Frontier Formation in the Wind River Basin, ranging in thickness from 650 to 1,000 ft thick, consists mainly of sandstone, siltstone, shale, and bentonite of early Late Cretaceous age. The Frontier conformably overlies the Mowry Shale and is conformably overlain by the Cody Shale. A basal unit of the Cody, a sequence of marine noncalcareous shale, is named the Sage Breaks Member. The Frontier consists of two or three members, separated by disconformities; in ascending order, the Belle Fourche, Emigrant Gap, and Wall Creek. At several localities, the Emigrant Gap Member is missing. The formation was deposited mainly in marine environments, although nonmarine beds are conspicuous in the western part of the basin. Strata of the Frontier record a succession of marine regressions and transgressions. Molluscan fossils from the marine beds were identified and related to the chronostratigraphic chart shown in figure 2. The absolute ages on the chart were determined and supplied by J.D. Obradovich (Cobban and others, 2006). In this region, the Belle Fourche is of Cenomanian age, the Emigrant Gap is of early middle Turonian age, and the Wall Creek is of late Turonian and early Coniacian ages. The main purpose of this report is to present biostratigraphic information from studies of the Frontier Formation in the Wind River Basin that could be useful for future stratigraphic investigations of the formation throughout Wyoming. Locations of outcrop sections and associated fossil collections are depicted on accompanying maps and aerial photographs. Graphic descriptions of strata in the outcrops and identifications of fossils from nearby localities also are presented. Those fossils named on the graphic sections commonly have the most restricted time-spans. Fossils collected near the outcrops studied are not always named on the enclosed graphic sections because (1) the specimens are less useful for dating the enclosing beds, (2) the specimens are duplicates, or (3) the specimens could not be related to specific strata in the sections. The names, locations, and members of the outcrop sections and the approximate ages of the constituent strata are summarized in table 1. The index maps used to show locations of outcrop sections and fossil collections are from scanned versions of U.S. Geological Survey topographic maps of various scales and were obtained from TerraServer®. The portion of each map used depended on the areal distribution of the localities involved. The named quadrangles used for locality descriptions, however, all refer to 7½-minute, 1:24,000-scale quadrangles (for example, “Alcova”). The aerial photographs also are from TerraServer®; http://www.terraserver.com/.

Wyoming↗
USGS2017

Lichens and microfungi in biocrusts: Structure and function now and in the future

Biological soil crusts (biocrusts) are formed by soil-surface communities of biota that live within, or immediately on top of, the uppermost millimeters of soil. They consist of cyanobacteria, algae, mosses, microfungi, and lichenized fungi (hereafter, lichens). Cyanobacterial and microfungal filaments, rhizinae and rhizomorphs of lichens, and rhizinae and protonemata of bryophytes weave throughout the top few millimeters of soil, gluing loose soil particles together (Fig. 1). The intimate association between soil particles and organisms forms a coherent crust. A quantitative estimate of global biological crust cover is difficult to obtain and not yet available, but the worldwide coverage of the terrestrial surface by biocrusts is very high. In arid and semiarid areas, biocrusts may constitute up to or more than 70% of the living cover and dryland (hyper-arid, arid, semi-arid, and polar deserts) ecosystems, where they often dominate, cover ~40% of the terrestrial land mass (Pointing and Belnap 2014). Lichens and microfungi are an essential and often dominant part of biocrusts. About one fifth (19 %) of all known species of fungi are lichenized; that is, they form a stable symbiotic association with green algal or/and cyanobacterial photobionts that provide nutrients for the mycobiont (fungi). The vast majority of lichenized fungi belong to the Ascomycota, with 42% of all fungi in this group forming lichens (Kirk et al., 2001). About 85% of lichen-forming fungi are symbiotic with Chlorophyta (green algae, creating "chlorolichens), approximately 10% with Cyanophyta, (creating "cyanolichens"), and the remainder are associated simultaneously with both groups. About 40 genera of photobionts have been identified in lichens: 25 are green algae and 15 are cyanobacteria. The autotrophic lifestyle of lichens requires an exposure of the green thallus to light. Most lichens are long-lived organisms with high habitat specificity. They are especially ecologically successful in dryland areas where competition with phanerogamous vegetation is reduced. It is estimated that approximately 8% of the earth's terrestrial surface has lichens as its most dominant life-form (Ahmadjian 1995). One of their most important habitats are biocrusts, which lichens often dominate. In the present Chapter we concentrate on those widely distributed biocrusts in which free-living and lichenized fungi play a dominating role. We describe their community structure, analyze the special properties and functions of these organisms as key members of biocrusts, and then discuss the function of the fungi-rich biocrusts as components of larger ecosystems and landscapes (for details and specific literature, see Belnap and Lange 2003).

Book chapter↗