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USGS2026

Comparing DESIS hyperspectral and Landsat 10 simulated superspectral data for crop type classification in California's Central Valley

To advance crop type mapping in support of global food and water security, this study compared three spectral configurations: (A) the full 60-band DLR Earth Sensing Imaging Spectrometer (DESIS) hyperspectral narrowband (HNB) dataset, (B) a 14-band subset of DESIS-derived HNBs aligned with the planned Landsat 10 (formerly Landsat Next) spectral configuration (400–1000 nm), and (C) DESIS-based simulations of Landsat 10 superspectral broadbands. The analysis was conducted in California’s Central Valley, hereafter referred to as “the Central Valley”, during the peak growing month of August. DESIS imagery from August 2021, 2022, and 2023 was used sequentially for model development, testing, and independent validation. Over these three years, DESIS provided extensive hyperspectral coverage of much of the 4 million hectares in the Central Valley’s. Analyses were performed on Google Earth Engine using two pixel-based supervised classifiers, Random Forest (RF) and Support Vector Machine (SVM), to differentiate three major crop classes: row crops, grapes and tree crops, and winter wheat/fallow/other. The highest overall accuracy (86%) was achieved using SVM in combination with either the full DESIS hyperspectral dataset or the 14 DESIS narrowbands corresponding to Landsat 10. This finding aligns with earlier studies showing a small number of strategically positioned narrowbands can be optimal for crop type classification. Use of the narrowband datasets resulted in substantially higher accuracy (overall accuracy of 86%) compared to the simulated Landsat 10 broadbands (overall accuracy of 75%), supporting previous studies highlighting the utility of narrowbands. Despite the high accuracy using August imagery, the study indicates more granular crop type classification will require multi-temporal observations spanning the full phenological cycle (June–October), especially for a large number of crop classes. Acquiring task-based hyperspectral imagery over such large areas throughout the growing season remains operationally challenging. In contrast, Landsat 10 superspectral imagery could provide routine coverage across seasons and years that is practical and scalable for future large area crop type mapping and agricultural monitoring.

California↗

USGS2019

Heat accumulation on coral reefs mitigated by internal waves

Coral reefs are among the most species-rich, productive and economically valuable ecosystems on Earth but increasingly frequent pantropical coral bleaching events are threatening their persistence on a global scale. The 2015–2016 El Niño led to the hottest sea surface temperatures on record and widespread bleaching of shallow-water corals. However, the causes of spatial variation in bleaching are poorly understood, and near-surface estimates of heat stress, such as those inferred from satellites, cannot be generalized across the broad depth ranges occupied by corals. Here, using in situ temperatures recorded across reefs from the near surface to 30–50 m depths in the western, central and eastern Pacific, we show that during the peak of the 2015–2016 anomaly, temperature fluctuations associated with internal waves reduced cumulative heat exposure by up to 88%. The durations of severe thermal anomalies above 8 °C-days, at which point widespread coral bleaching and mortality are likely, were also decreased by >36% at some sites and were prevented entirely at others. The impact of internal waves across depths on coral reefs has the potential to create and support thermal refuges in which heat stress and coral bleaching risk may be modulated, but future effects depend on the response of internal wave climates to continued warming and strengthening ocean stratification.

Nature Geoscience↗

USGS2013

Geodatabase compilation of hydrogeologic, remote sensing, and water-budget-component data for the High Plains aquifer, 2011

The High Plains aquifer underlies almost 112 million acres in the central United States. It is one of the largest aquifers in the Nation in terms of annual groundwater withdrawals and provides drinking water for 2.3 million people. The High Plains aquifer has gained national and international attention as a highly stressed groundwater supply primarily because it has been appreciably depleted in some areas. The U.S. Geological Survey has an active program to monitor the changes in groundwater levels for the High Plains aquifer and has documented substantial water-level changes since predevelopment: the High Plains Groundwater Availability Study is part of a series of regional groundwater availability studies conducted to evaluate the availability and sustainability of major aquifers across the Nation. The goals of the regional groundwater studies are to quantify current groundwater resources in an aquifer system, evaluate how these resources have changed over time, and provide tools to better understand a systems response to future demands and environmental stresses. The purpose of this report is to present selected data developed and synthesized for the High Plains aquifer as part of the High Plains Groundwater Availability Study. The High Plains Groundwater Availability Study includes the development of a water-budget-component analysis for the High Plains completed in 2011 and development of a groundwater-flow model for the northern High Plains aquifer. Both of these tasks require large amounts of data about the High Plains aquifer. Data pertaining to the High Plains aquifer were collected, synthesized, and then organized into digital data containers called geodatabases. There are 8 geodatabases, 1 file geodatabase and 7 personal geodatabases, that have been grouped in three categories: hydrogeologic data, remote sensing data, and water-budget-component data. The hydrogeologic data pertaining to the northern High Plains aquifer is included in three separate geodatabases: (1) base data from a groundwater-flow model; (2) hydrogeology and hydraulic properties data; and (3) groundwater-flow model data to be used as calibration targets. The remote sensing data for this study were developed by the U. S. Geological Survey Earth Resources Observation and Science Center and include historical and predicted land-use/land-cover data and actual evapotranspiration data by using remotely sensed temperature data. The water-budget-component data contains selected raster data from maps in the “Selected Approaches to Estimate Water-Budget Components of the High Plains, 1940 Through 1949 and 2000 Through 2009” report completed in 2011 ( http://pubs.usgs.gov/sir/2011/5183/ ). Federal Geographic Data Committee compliant metadata were created for each spatial and tabular data layer in the geodatabases.

Colorado, Kansas, Nebraska, New Mexico, Oklahoma, ↗

USGS2007

Long-term perspectives on giant earthquakes and tsunamis at subduction zones

Histories of earthquakes and tsunamis, inferred from geological evidence, aid in anticipating future catastrophes. This natural warning system now influences building codes and tsunami planning in the United States, Canada, and Japan, particularly where geology demonstrates the past occurrence of earthquakes and tsunamis larger than those known from written and instrumental records. Under favorable circumstances, paleoseismology can thus provide long-term advisories of unusually large tsunamis. The extraordinary Indian Ocean tsunami of 2004 resulted from a fault rupture more than 1000 km in length that included and dwarfed fault patches that had broken historically during lesser shocks. Such variation in rupture mode, known from written history at a few subduction zones, is also characteristic of earthquake histories inferred from geology on the Pacific Rim. Copyright ?? 2007 by Annual Reviews. All rights reserved.

Annual Review of Earth and Planetary Sciences↗

USGS2016

Post-Hurricane Irene coastal oblique aerial photographs collected from Ocracoke Inlet, North Carolina, to Virginia Beach, Virginia, August 30-31, 2011

The U.S. Geological Survey (USGS), as part of the National Assessment of Coastal Change Hazards project, conducts baseline and storm-response photography missions to document and understand the changes in vulnerability of the Nation's coasts to extreme storms (Morgan, 2009). On August 30-31, 2011, the USGS conducted an oblique aerial photographic survey from Ocracoke Inlet, North Carolina, to Virginia Beach, Virginia, aboard a Piper Navajo Chieftain (aircraft) at an altitude of 500 feet (ft) and approximately 1,200 ft offshore. This mission was flown to collect post-Hurricane Irene data for assessing incremental changes in the beach and nearshore area since the last survey, flown in May 2008, and the data can be used in the assessment of future coastal change. The photographs provided in this report 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 at the time the photograph was taken and do not indicate the location of any feature in the images (see the Navigation Data page). These photographs document the state 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 segments 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, image name, date, and time for each of the 2,688 photographs that were taken along with links to each photograph. 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 also shows the track of Hurricane Irene. The KML files were created using the photographic navigation files. These KML file(s) can be found in the kml folder.

North Carolina, Virginia↗

USGS1993

The U. S. Geological Survey, Digital Spectral Library: Version 1 (0.2 to 3.0um)

We have developed a digital reflectance spectral library, with management and spectral analysis software. The library includes 498 spectra of 444 samples (some samples include a series of grain sizes) measured from approximately 0.2 to 3.0 um . The spectral resolution (Full Width Half Maximum) of the reflectance data is <= 4 nm in the visible (0.2-0.8 um) and <= 10 nm in the NIR (0.8-2.35 um). All spectra were corrected to absolute reflectance using an NIST Halon standard. Library management software lets users search on parameters (e.g. chemical formulae, chemical analyses, purity of samples, mineral groups, etc.) as well as spectral features. Minerals from borate, carbonate, chloride, element, halide, hydroxide, nitrate, oxide, phosphate, sulfate, sulfide, sulfosalt, and the silicate (cyclosilicate, inosilicate, nesosilicate, phyllosilicate, sorosilicate, and tectosilicate) classes are represented. X-Ray and chemical analyses are tabulated for many of the entries, and all samples have been evaluated for spectral purity. The library also contains end and intermediate members for the olivine, garnet, scapolite, montmorillonite, muscovite, jarosite, and alunite solid-solution series. We have included representative spectra of H2O ice, kerogen, ammonium-bearing minerals, rare-earth oxides, desert varnish coatings, kaolinite crystallinity series, kaolinite-smectite series, zeolite series, and an extensive evaporite series. Because of the importance of vegetation to climate-change studies we have include 17 spectra of tree leaves, bushes, and grasses. The library and software are available as a series of U.S.G.S. Open File reports. PC user software is available to convert the binary data to ascii files (a separate U.S.G.S. open file report). Additionally, a binary data files are on line at the U.S.G.S. in Denver for anonymous ftp to users on the Internet. The library search software enables a user to search on documentation parameters as well as spectral features. The analysis system includes general spectral analysis routines, plotting packages, radiative transfer software for computing intimate mixtures, routines to derive optical constants from reflectance spectra, tools to analyze spectral features, and the capability to access imaging spectrometer data cubes for spectral analysis. Users may build customized libraries (at specific wavelengths and spectral resolution) for their own instruments using the library software. We are currently extending spectral coverage to 150 um. The libraries (original and convolved) will be made available in the future on a CD-ROM.

Open-File Report↗

USGS2008

Petrology of the 2004-2006 Mount St. Helens lava dome -- implications for magmatic plumbing and eruption triggering

Eighteen years after dome-forming eruptions ended in 1986, and with little warning, Mount St. Helens began to erupt again in October 2004. During the ensuing two years, the volcano extruded more than 80×10 6 m 3 of gas-poor, crystal-rich dacite lava. The 2004-6 dacite is remarkably uniform in bulk-rock composition and, at 65 percent SiO 2 , among the richest in silica and most depleted in incompatible elements of the magmas erupted at Mount St. Helens during the past 500 years. Since shortly after the first spine of lava appeared, samples have been collected using a steel box dredge (“Jaws”) suspended 20-35 m below a helicopter and, occasionally, by hand sampling. As of the spring of 2006, 25 age-controlled samples have been collected from the seven spines of the new lava dome. Samples were obtained from both the interiors of spines and from their carapaces, which are composed of fault gouge and cataclasite 1-2 m thick. The dacite lava is crystal rich, with 40-50 percent phenocrysts. The groundmass is extensively crystallized to a cotectic assemblage of quartz, tridymite, and Na- and K-rich feldspar microlites, raising the total crystal content to more than 80 percent on a vesicle-free basis in all but the earliest erupted samples. Early samples and those collected from near the spine margin are more glassy and vesicular that those collected later and from the interior of the spines. Oxide thermobarometer determinations for the earliest erupted samples we collected cluster at temperatures of approximately 850°C and at an oxygen fugacity one log unit above the nickel-nickel oxide (NNO) buffer curve. In contrast, samples from relatively glass-poor samples erupted in late 2004 and early 2005 have zoned oxides with apparent temperatures that range to greater than 950°C. The higher temperatures in these microlite-rich rocks are attributed to latent heat evolved during extensive and rapid groundmass crystallization. Low volatile contents of matrix glasses and presence of tridymite and quartz in the high-silica rhyolite matrix glass indicate extensive shallow (<1 km) crystallization of the matrix, driven by degassing of water and solidifying the magma below the level of the vent. The mode of eruption of the dacite as a series of fault-gouge-mantled spines is explained by this process of extensive subvent degassing and solidification. Although the dacite from this eruption is more silica rich than 1980-86 dome rocks, most major and trace element concentrations of the 1980-86 and 2004-6 magma batches are similar, and magmatic gas emissions have been low and have had similar ratios to those of the 1980s, raising the possibility that the magma might be residual from the 1980–86 reservoir. However, titanium and chromium are enriched slightly relative to the most recent 1980-86 and Goat Rocks (A.D. 1800-1857) eruptive cycles, and heavy rare-earth-element abundances are slightly depleted relative to those erupted during the past 500 years at Mount St. Helens. These data suggest either addition of new gas-poor dacite magma or tapping of a region of the preexisting reservoir that was not erupted previously. A relatively low pressure of last phenocryst growth suggests that the magma was derived from near the apex of the Mount St. Helens magma reservoir at a depth of about 5 km. Viewed in the context of seismic, deformation, and gas-emission data, the petrologic and geochemical data can be explained by ascent of a geochemically distinct batch of magma into the apex of the reservoir during the period 1987-97, followed by upward movement of magma into a new conduit beginning in late September 2004. The question of new versus residual magma has implications for the long-term eruptive behavior of Mount St. Helens, because arrival of a new batch of dacitic magma from the deep crust could herald the beginning of a new long-term cycle of eruptive activity. It is also important to our understanding of what triggered the eruption and its future course. Two hypotheses for triggering are considered: (1) top-down fracturing related to the shallow groundwater system and (2) an increase in reservoir pressure brought about by recent magmatic replenishment. With respect to the future course of the eruption, similarities between textures and character of eruption of the 2004-6 dome and the long-duration (greater than 100 years) pre-1980 summit dome, along with the low eruptive rate of the current eruption, suggest that the eruption could continue sluggishly or intermittently for years to come.

Washington↗

USGS2006

Comprehensive water quality of the Boulder Creek Watershed, Colorado, during high-flow and low-flow conditions, 2000

Executive Summary The Boulder Creek Watershed, Colorado, is 1160 square kilometers in area and ranges in elevation from 1480 to 4120 meters above sea level. Streamflow originates primarily as snowmelt near the Continental Divide, and thus discharge varies seasonally and annually (Chapter 1). Most of the water in Boulder Creek is diverted for domestic, agricultural, and industrial use. Some diverted water is returned to the creek as wastewater effluent and by ditch returns, and additional water enters as groundwater and by transbasin diversions. These diversions and returns lead to complex temporal and spatial variations in discharge. The variations in discharge, along with natural factors such as geology and climate, and anthropogenic factors such as wastewater treatment, agriculture, mining, and urbanization, can affect water chemistry. As with many watersheds in the American West, dependable water quality and sufficient water supply are issues facing local water managers and users. Detailed water-quality and sediment sampling allows the identification of sources and sinks of chemical constituents and an understanding of the processes at work in a river system. This study, the most comprehensive water-quality analysis performed for Boulder Creek to date, was a cooperative effort of the U.S. Geological Survey (USGS) and the city of Boulder. Geographic information systems and modeling programs were used to delineate watershed boundaries, land cover, and geology (Chapter 2). During high-flow (June 2000) and low-flow (October 2000) conditions, researchers evaluated 226 water-quality variables, including basic water-quality indicators (Chapter 3), major ions and trace elements (Chapter 4), wastewater-derived organic compounds (Chapter 5), and pesticides (Chapter 6). Discharge (Chapter 1) and bed-sediment particle size and mineralogy (Chapter 7) were also evaluated. This cooperative study was facilitated by the Boulder Area Sustainability Information Network (BASIN), which provides public access to environmental information about the Boulder Creek Watershed on a website, www.basin.org. In addition to the USGS and city of Boulder data, researchers at the Institute of Arctic and Alpine Research at the University of Colorado provided water chemistry data for the headwaters of North Boulder Creek, upstream of the reach of the USGS/city of Boulder sampling sites (Chapter 8). Snowmelt produces high flows in Boulder Creek in late spring to early summer (Chapter 1). Because precipitation falling in the headwaters is very dilute (specific conductance about 5 microsiemens per centimeter), most chemical constituents are present in lower concentrations during high flows (Chapters 3, 4, 5, 6, and 8). However, concentrations of some constituents, such as total suspended solids (Chapter 3) and organic carbon (Chapter 5), increase during the spring snowmelt flush. The upper basin, which consists of alpine, subalpine, montane, and foothills regions west of the mouth of Boulder Canyon, is underlain by Precambrian igneous and metamorphic rocks (Chapter 1). Major dissolved inorganic constituents in headwater sites were found to be enriched by factors of 10 to 20 relative to precipitation; this is consistent with minor weathering of the local crystalline bedrock (Chapter 4). Some anthropogenic input is observed in the headwaters; precipitation introduces nitrogen derived from fossil fuel combustion and agricultural activities (Chapter 8). The lower basin, which consists of the plains region east of the mouth of Boulder Canyon, is underlain by Mesozoic sedimentary rock and Quaternary alluvium, and has substantially more anthropogenic sources. Concentrations of most dissolved inorganic constituents increased in the lower basin. Differentiation between natural and anthropogenic sources of some dissolved constituents is difficult because both sources contribute to the water composition in this region. The increase of most major constituents (bicarbonate, calcium, chloride, magnesium, sodium, and sulfate) is consistent with weathering of the underlying sedimentary bedrock (Chapter 4). It is likely that anthropogenic loading of constituents in this reach occurs during storm events. Fecal coliform concentrations were variable and in some cases exceeded state standards, primarily during low-flow conditions (Chapter 3). Effluent from Boulder’s 75th Street Wastewater Treatment Plant (WWTP) has a substantial impact on the water chemistry of lower Boulder Creek. The WWTP increases the concentrations of nutrients such as nitrogen and phosphorus (Chapter 3), major ions and trace metals (Chapter 4), and organic carbon (Chapter 5) in Boulder Creek. The effluent contained a spike in gadolinium, a rare earth element that is ingested for magnetic resonance imaging as a contrasting agent and then excreted to the urban wastewater system. The effluent also contained trace organic compounds such as surfactants, pharmaceuticals, hormones (Chapter 5), and pesticides (Chapter 6), which also were detected at downstream Boulder Creek sites. Water chemistry of Boulder Creek downstream of the WWTP is largely controlled by the degree of dilution of the wastewater effluent, which varies depending on the baseflow of Boulder Creek, the volume of wastewater effluent, and depletion by agricultural diversions. Coal Creek, a tributary of Boulder Creek, contains wastewater effluent from four additional WWTPs, and increases the load of many constituents in Boulder Creek. In addition to the impact from wastewater effluent, lower Boulder Creek is affected by agricultural land use. Eleven of 84 analyzed pesticides were detected in Boulder Creek or its inflows, primarily in the eastern section of the watershed (Chapter 6). This collaborative study provides an in-depth evaluation of the hydrology, water chemistry, and sediment mineralogy of North Boulder Creek, Middle Boulder Creek, Boulder Creek, and major inflows. The detailed sampling and analysis in this report provide a baseline for future reference, as well as information on the effect of land use and geology on water chemistry.

Colorado↗

USGS2024

Multiple stressors mediate the effects of warming on leaf decomposition in a large regulated river

Predicting how increasing temperatures interact with other global change drivers to influence the structure and dynamics of Earth's ecosystems is a primary challenge in ecology. Our study made use of multiple simultaneous “natural experiments” to examine how rapid warming, declining nutrients, invasive consumers, and riparian invasive species management interact to influence leaf decomposition in a large and regulated river. Specifically, we compared the breakdown of cottonwood ( Populus fremontii ), willow ( Salix exigua ), and saltcedar ( Tamarix sp.) leaf litter in 2022 to a previous experiment from 1998 that occurred under much cooler water temperatures, and had higher water phosphorus concentrations, low numbers of invasive New Zealand mudsnails ( Potamopyrgus antipodarum ), and unaltered litter chemistry from the herbivory of saltcedar leaf beetles ( Diorhabda carinulata ). We found that the effects of up to 10°C warmer temperatures on leaf decomposition were mediated by the establishment and management of invasive species and declining water nutrient concentrations arising from upstream reservoir lowering. Such interactions led to accelerated breakdown of saltcedar, but relatively minor effects of warming on the rate of cottonwood and willow decomposition. Additionally, our results demonstrate the potential for favorable invasive species management outcomes in the terrestrial environment to produce unintended responses in adjacent freshwater ecosystems. As temperatures continue to rise, it is critical that future studies consider how warming interacts with multiple stressors and environmental factors to influence processes such as decomposition in freshwater ecosystems.

Arizona↗

USGS2020

Does Lake Erie still have sufficient oxythermal habitat for cisco Coregonus artedi ?

In Lake Erie, cisco Coregonus artedi once supported one of the most valuable freshwater fisheries on earth, yet overfishing caused their eventual extirpation from the lake. With warming lake temperatures, some have questioned whether Lake Erie still contains suitable oxythermal conditions for cisco. Using published oxythermal thresholds for cisco and oxythermal profiles from Lake Erie, we sought to answer two questions critical to cisco restoration science. First, is cisco habitat still available during the most restrictive periods? Second, what is the distribution of cisco habitat during these times? Beta regression was used to determine that cisco habitat was most limited during the month of August, and that August of 2010 was the most restrictive period in the time series. We then used Empirical Bayesian Kriging (EBK) to map the spatial extent of cisco habitat during these times. EBK maps revealed large areas of summer refugia for cisco in Lake Erie, even during the least favorable periods. Most of the Central and East Basins contain suitable habitat during the average August, yet during August of 2010, suitable conditions were limited to the eastern edge of the Central Basin and the deep waters of the East Basin. These findings align well with historical accounts of cisco landings. While suitable oxythermal habitat still exists for cisco in Lake Erie, future restoration efforts, if attempted, will partially depend on: 1) better management of nutrient inputs, 2) the realization of future climate scenarios, and 3) the ability of cisco to adapt to a changing lake.

Lake Erie↗

USGS2015

Post-Hurricane Ivan coastal oblique aerial photographs collected from Crawfordville, Florida, to Petit Bois Island, Mississippi, September 17, 2004

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 September 17, 2004, the USGS conducted an oblique aerial photographic survey from Crawfordville, Florida, to Petit Bois Island, Mississippi aboard a Piper Navajo Chieftain (aircraft) at an altitude of 500 feet (ft) and approximately 1,000 ft offshore. This mission was flown to collect post-Hurricane Ivan data for assessing incremental changes in the beach and nearshore area since the last survey in 2001, and the data can be used in the assessment of future coastal change. The images provided in this report 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. These photographs document the state 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 segments can be found on the Photos and Maps page. The 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, image name, date, and time for each of the 3,381 photographs taken, along with links to each photograph. The photographs are organized into segments, also referred to as contact sheets, and represent approximately 5 minutes of flight time. In addition to the photographs, a Google Earth Keyhole Markup Language (KML) file is provided, which 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, Mississippi↗

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↗

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↗