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At least 1,333 records · Page 74Linked to original sources
USGS2001

Surface-water, water-quality, and ground-water assessment of the Municipio of Carolina, Puerto Rico, 1997-99

To meet the increasing need for a safe and adequate supply of water in the municipio of Carolina, an integrated surface-water, water-quality, and ground-water assessment of the area was conducted. The major results of this study and other important hydrologic and water-quality features were compiled in a Geographic Information System and are presented in two 1:30,000-scale map plates to facilitate interpretation and use of the diverse water-resources data. Because the supply of safe drinking water was a critical issue during recent dry periods, the surface-water assessment portion of this study focused on analysis of low-flow characteristics in local streams and rivers. Low-flow characteristics were evaluated for one continuous-record gaging station, based on graphical curve-fitting techniques and log-Pearson Type III frequency analysis. Estimates of low-flow characteristics for seven partial-record stations were generated using graphical-correlation techniques. Flow-duration characteristics were computed for the one continuous-record gaging station and were estimated for the partial-record stations using the relation curves developed from the low-flow study. Stream low-flow statistics document the general hydrology under current land and water use. Low-flow statistics may substantially change as a result of streamflow diversions for public supply, and an increase in ground-water development, waste-water discharges, and flood-control measures; the current analysis provides baseline information to evaluate these impacts and develop water budgets. A sanitary quality survey of streams utilized 29 sampling stations to evaluate the sanitary quality of about 87 miles of stream channels. River and stream samples were collected on two occasions during base-flow conditions and were analyzed for fecal coliform and fecal streptococcus. Bacteriological analyses indicate that a significant portion of the stream reaches within the municipio of Carolina may have fecal coliform concentrations above the water-quality goal established by the Puerto Rico Environmental Quality Board (Junta de Calidad Ambiental de Puerto Rico) for inland surface waters. Sources of fecal contamination may include: illegal discharge of sewage to storm-water drains, malfunctioning sanitary sewer ejectors, clogged and leaking sewage pipes, septic tank leakage, unfenced livestock, and runoff from livestock pens. Long-term fecal coliform data at two sampling stations, Quebrada Blasina in Carolina and the Rio Grande de Loiza, downstream from the town of Trujillo Alto, indicate that the sanitary quality of Quebrada Blasina is and has generally been poor for more than a decade. The sanitary quality of the Rio Grande de Loiza has generally been in compliance with the water-quality goal standard fecal coliform concentrations established in July 1990 by the Puerto Rico Environmental Quality Board. Geologic, topographic, soil, hydrogeologic, and streamflow data were used to divide the municipio of Carolina into five hydrogeologic terranes. This integrated database was then used to evaluate the ground-water potential of each hydrogeologic terrane. Analysis suggests that areas with slopes greater than 15 degrees have relatively low ground-water development potential. Fractures may be locally important in enhancing the water-bearing properties in the hydrogeologic terranes containing igneous rocks. Potentiometric-surface elevations recorded in piezometers installed in the coastal area during this study were used to define ground-water flow directions in the hydrogeologic terranes composed of coastal plain clastic and limestone units. The resultant potentiometric map indicates that the coastal plain aquifer and streams in the lowland parts of the municipio of Carolina are hydraulically connected. The potentiometric map also indicates that ground-water discharge to the Rio Grande de Loiza, downstream from highway PR-3, has been enhanced by dredging of the streambed for

Water-Resources Investigations Report↗
USGS2016

Active faulting on the Wallula fault zone within the Olympic-Wallowa lineament, Washington State, USA

The Wallula fault zone is an integral feature of the Olympic-Wallowa lineament, an ∼500-km-long topographic lineament oblique to the Cascadia plate boundary, extending from Vancouver Island, British Columbia, to Walla Walla, Washington. The structure and past earthquake activity of the Wallula fault zone are important because of nearby infrastructure, and also because the fault zone defines part of the Olympic-Wallowa lineament in south-central Washington and suggests that the Olympic-Wallowa lineament may have a structural origin. We used aeromagnetic and ground magnetic data to locate the trace of the Wallula fault zone in the subsurface and map a quarry exposure of the Wallula fault zone near Finley, Washington, to investigate past earthquakes along the fault. We mapped three main packages of rocks and unconsolidated sediments in an ∼10-m-high quarry exposure. Our mapping suggests at least three late Pleistocene earthquakes with surface rupture, and an episode of liquefaction in the Holocene along the Wallula fault zone. Faint striae on the master fault surface are subhorizontal and suggest reverse dextral oblique motion for these earthquakes, consistent with dextral offset on the Wallula fault zone inferred from offset aeromagnetic anomalies associated with ca. 8.5 Ma basalt dikes. Magnetic surveys show that the Wallula fault actually lies 350 m to the southwest of the trace shown on published maps, passes directly through deformed late Pleistocene or younger deposits exposed at Finley quarry, and extends uninterrupted over 120 km.

Washington↗
USGS2010

Ensemble habitat mapping of invasive plant species

Ensemble species distribution models combine the strengths of several species environmental matching models, while minimizing the weakness of any one model. Ensemble models may be particularly useful in risk analysis of recently arrived, harmful invasive species because species may not yet have spread to all suitable habitats, leaving species-environment relationships difficult to determine. We tested five individual models (logistic regression, boosted regression trees, random forest, multivariate adaptive regression splines (MARS), and maximum entropy model or Maxent) and ensemble modeling for selected nonnative plant species in Yellowstone and Grand Teton National Parks, Wyoming; Sequoia and Kings Canyon National Parks, California, and areas of interior Alaska. The models are based on field data provided by the park staffs, combined with topographic, climatic, and vegetation predictors derived from satellite data. For the four invasive plant species tested, ensemble models were the only models that ranked in the top three models for both field validation and test data. Ensemble models may be more robust than individual species-environment matching models for risk analysis. ?? 2010 Society for Risk Analysis.

Risk Analysis↗
USGS1973

Atlas of Mars, Phoenicis Lacus quadrangle, MC-17

This mosaic is made with computer enhanced Mariner 9 pictures, rectified and scaled to a Mercator projection. Computer processing was performed by the Image Processing Laboratory (IPL) of the Jet Propulsion Laboratory (JPL). Processing included contrast enhancement and high-pass filtering which accentuates topographic features while subduing albedo variations. Photographic reproductions of the images were generated from the IPL digital magnetic tapes and mosaicked by the U.S. Geological Survey. Horizontal controls were derived from spacecraft tracking data, which are based on astronomical definitions of the spin axis and system of longitudes in use during the Mariner 9 mission. The projection is based on a theoretical dynamical ellipticity of 1/192. The scale is based on an equatorial radius of 3393.4 km. Standard deviation in image placement is less than 5 km at map scale.

Open-File Report↗
USGS2007

Predicting wetland plant community responses to proposed water-level-regulation plans for Lake Ontario: GIS-based modeling

Integrated, GIS-based, wetland predictive models were constructed to assist in predicting the responses of wetland plant communities to proposed new water-level regulation plans for Lake Ontario. The modeling exercise consisted of four major components: 1) building individual site wetland geometric models; 2) constructing generalized wetland geometric models representing specific types of wetlands (rectangle model for drowned river mouth wetlands, half ring model for open embayment wetlands, half ellipse model for protected embayment wetlands, and ellipse model for barrier beach wetlands); 3) assigning wetland plant profiles to the generalized wetland geometric models that identify associations between past flooding / dewatering events and the regulated water-level changes of a proposed water-level-regulation plan; and 4) predicting relevant proportions of wetland plant communities and the time durations during which they would be affected under proposed regulation plans. Based on this conceptual foundation, the predictive models were constructed using bathymetric and topographic wetland models and technical procedures operating on the platform of ArcGIS. An example of the model processes and outputs for the drowned river mouth wetland model using a test regulation plan illustrates the four components and, when compared against other test regulation plans, provided results that met ecological expectations. The model results were also compared to independent data collected by photointerpretation. Although data collections were not directly comparable, the predicted extent of meadow marsh in years in which photographs were taken was significantly correlated with extent of mapped meadow marsh in all but barrier beach wetlands. The predictive model for wetland plant communities provided valuable input into International Joint Commission deliberations on new regulation plans and was also incorporated into faunal predictive models used for that purpose.

Journal of Great Lakes Research↗
USGS2016

Topobathymetric elevation model development using a new methodology: Coastal National Elevation Database

During the coming decades, coastlines will respond to widely predicted sea-level rise, storm surge, and coastalinundation flooding from disastrous events. Because physical processes in coastal environments are controlled by the geomorphology of over-the-land topography and underwater bathymetry, many applications of geospatial data in coastal environments require detailed knowledge of the near-shore topography and bathymetry. In this paper, an updated methodology used by the U.S. Geological Survey Coastal National Elevation Database (CoNED) Applications Project is presented for developing coastal topobathymetric elevation models (TBDEMs) from multiple topographic data sources with adjacent intertidal topobathymetric and offshore bathymetric sources to generate seamlessly integrated TBDEMs. This repeatable, updatable, and logically consistent methodology assimilates topographic data (land elevation) and bathymetry (water depth) into a seamless coastal elevation model. Within the overarching framework, vertical datum transformations are standardized in a workflow that interweaves spatially consistent interpolation (gridding) techniques with a land/water boundary mask delineation approach. Output gridded raster TBDEMs are stacked into a file storage system of mosaic datasets within an Esri ArcGIS geodatabase for efficient updating while maintaining current and updated spatially referenced metadata. Topobathymetric data provide a required seamless elevation product for several science application studies, such as shoreline delineation, coastal inundation mapping, sediment-transport, sea-level rise, storm surge models, and tsunami impact assessment. These detailed coastal elevation data are critical to depict regions prone to climate change impacts and are essential to planners and managers responsible for mitigating the associated risks and costs to both human communities and ecosystems. The CoNED methodology approach has been used to construct integrated TBDEM models in Mobile Bay, the northern Gulf of Mexico, San Francisco Bay, the Hurricane Sandy region, and southern California.

Journal of Coastal Research↗
USGS2009

Age, geochemical composition, and distribution of Oligocene ignimbrites in the northern Sierra Nevada, California: Implications for landscape morphology, elevation, and drainage divide geography of the Nevadaplano

To gain a better understanding of the topographic and landscape evolution of the Cenozoic Sierra Nevada and Basin and Range, we combine geochemical and isotopic age correlations with palaeoaltimetry data from widely distributed ignimbrites in the northern Sierra Nevada, California. A sequence of Oligocene rhyolitic ignimbrites is preserved across the modern crest of the range and into the western foothills. Using trace and rare earth element geochemical analyses of volcanic glass, these deposits have been correlated to ignimbrites described and isotopically dated in the Walker Lane fault zone and in central Nevada (Henry et al. , 2004, Geologic map of the Dogskin mountain quadrangle; Washoe County, Nevada; Faulds et al. , 2005, Geology, v. 33, p. 505–508). Ignimbrite deposits were sampled within the northern Sierra Nevada and western Nevada, and four distinct geochemical compositions were identified. The majority of samples from within the northern Sierra Nevada have compositions similar to the tuffs of Axehandle Canyon or Rattlesnake Canyon, both likely sourced from the same caldera complex in either the Clan Alpine Mountains or the Stillwater Range, or to the tuff of Campbell Creek, sourced from the Desatoya Mountains caldera. New 40 Ar/ 39 Ar age determinations from these samples of 31.2, 30.9, and 28.7 Ma, respectively, support these correlations. Based on an Oligocene palinspastic reconstruction of the region, our results show that ignimbrites travelled over 200 km from their source calderas across what is now the crest of the Sierra Nevada, and that during that time, no drainage divide existed between the ignimbrite source calderas in central Nevada and sample locations 200 km to the west. Palaeoaltimetry data from Sierra Nevada ignimbrites, based on the hydrogen isotopic composition of hydration water in glass, reflect the effect of a steep western slope on precipitation and indicate that the area had elevations similar to the present-day range. These combined results suggest that source calderas were likely located in a region of high elevation to the east of the Oligocene Sierra Nevada, which had a steep western slope that allowed for the large extent and broad distribution of the ignimbrites.

International Geology Review↗
USGS2003

Spatial variability of groundwater recharge and its effect on shallow groundwater quality in southern New Jersey

Point estimates of groundwater recharge at 48 sediment-coring locations vary substantially (−18.5–1840 cm yr −1 ) in a 930-km 2 area of southern New Jersey. Darcian estimates of steady, long-term recharge made at depth in the unsaturated zone were estimated using pedotransfer functions of soil texture and interpolated (mapped) with nonparametric methods to assess aquifer vulnerability in the area. The probability of exceeding the median recharge (29.1 cm yr −1 ) is low in the southwestern and northeastern portions of the study area and high in the eastern and southeastern portions. Estimated recharge is inversely related to measured percentage clay and positively related to the percentage of well-drained soils near wells. Spatial patterns of recharge estimates, exceedance probabilities, and clay content indicate that sediment texture controls recharge in the study area. Relations with land elevation and a topographic wetness index were statistically insignificant. Nitrate concentration and atrazine (6-chloro- N 2 -ethyl- N 4 -isopropyl-1,3,5-triazine-2,4-diamine) percentage detection in samples of shallow groundwater (typically <10 m) are higher for low recharge sites (≤29.1 cm yr −1 ) than for high recharge sites (>29.1 cm yr −1 ) in agricultural and urban areas. Differences between high and low recharge sites in these areas are highly significant for NO 3 concentration, but not for atrazine concentration.

New Jersey↗
USGS2008

Physiographically sensitive mapping of climatological temperature and precipitation across the conterminous United States

Spatial climate data sets of 1971–2000 mean monthly precipitation and minimum and maximum temperature were developed for the conterminous United States. These 30‐arcsec (∼800‐m) grids are the official spatial climate data sets of the U.S. Department of Agriculture. The PRISM (Parameter‐elevation Relationships on Independent Slopes Model) interpolation method was used to develop data sets that reflected, as closely as possible, the current state of knowledge of spatial climate patterns in the United States. PRISM calculates a climate–elevation regression for each digital elevation model (DEM) grid cell, and stations entering the regression are assigned weights based primarily on the physiographic similarity of the station to the grid cell. Factors considered are location, elevation, coastal proximity, topographic facet orientation, vertical atmospheric layer, topographic position, and orographic effectiveness of the terrain. Surface stations used in the analysis numbered nearly 13 000 for precipitation and 10 000 for temperature. Station data were spatially quality controlled, and short‐period‐of‐record averages adjusted to better reflect the 1971–2000 period. PRISM interpolation uncertainties were estimated with cross‐validation (C‐V) mean absolute error (MAE) and the 70% prediction interval of the climate–elevation regression function. The two measures were not well correlated at the point level, but were similar when averaged over large regions. The PRISM data set was compared with the WorldClim and Daymet spatial climate data sets. The comparison demonstrated that using a relatively dense station data set and the physiographically sensitive PRISM interpolation process resulted in substantially improved climate grids over those of WorldClim and Daymet. The improvement varied, however, depending on the complexity of the region. Mountainous and coastal areas of the western United States, characterized by sparse data coverage, large elevation gradients, rain shadows, inversions, cold air drainage, and coastal effects, showed the greatest improvement. The PRISM data set benefited from a peer review procedure that incorporated local knowledge and data into the development process.

International Journal of Climatology↗
USGS2016

High resolution mapping of development in the wildland-urban interface using object based image extraction

The wildland-urban interface (WUI), the area where human development encroaches on undeveloped land, is expanding throughout the western United States resulting in increased wildfire risk to homes and communities. Although census based mapping efforts have provided insights into the pattern of development and expansion of the WUI at regional and national scales, these approaches do not provide sufficient detail for fine-scale fire and emergency management planning, which requires maps of individual building locations. Although fine-scale maps of the WUI have been developed, they are often limited in their spatial extent, have unknown accuracies and biases, and are costly to update over time. In this paper we assess a semi-automated Object Based Image Analysis (OBIA) approach that utilizes 4-band multispectral National Aerial Image Program (NAIP) imagery for the detection of individual buildings within the WUI. We evaluate this approach by comparing the accuracy and overall quality of extracted buildings to a building footprint control dataset. In addition, we assessed the effects of buffer distance, topographic conditions, and building characteristics on the accuracy and quality of building extraction. The overall accuracy and quality of our approach was positively related to buffer distance, with accuracies ranging from 50 to 95% for buffer distances from 0 to 100 m. Our results also indicate that building detection was sensitive to building size, with smaller outbuildings (footprints less than 75 m 2 ) having detection rates below 80% and larger residential buildings having detection rates above 90%. These findings demonstrate that this approach can successfully identify buildings in the WUI in diverse landscapes while achieving high accuracies at buffer distances appropriate for most fire management applications while overcoming cost and time constraints associated with traditional approaches. This study is unique in that it evaluates the ability of an OBIA approach to extract highly detailed data on building locations in a WUI setting.

Colorado↗
USGS2014

Report of committee on glaciers, 1940–41

The personnel of the Committee is now as follows: Harry Fielding Reid, Professor Emeritus of Geology, Johns Hopkins University, 608 Cathedral Street, Baltimore, Maryland; William H. Hobbs, Professor Emeritus of Geology, University of Michigan, Ann Arbor, Michigan; Lawrence Martin, Chief of the Division of Maps, Library of Congress, Washington, D.C.; J. E. Church, Professor of Meteorology, Agricultural Experiment Station, University of Nevada, Reno, Nevada; Wm. Osgood Field, Jr., Explorer, 18 West Twelfth Street, New York, New York; Oliver Kehrlein, Chairman, Committee on Glacier Studies of Sierra Club, 1050 Mills Tower, 220 Bush Street, San Francisco, California; Kenneth N. Phillips, Associate Hydraulic Engineer, Water Resources Branch, United States Geological Survey, Chairman, Research Committee of the Mazamas, 606 Post‐Office Building, Portland, Oregon; William S. Cooper, Professor of Botany, University of Minnesota, Minneapolis, Minnesota; Gerald Fitzgerald, Senior Topographic Engineer, Alaska Branch, United States Geological Survey, Washington, D.C.; Laurence M. Gould, Professor of Geology, Carleton College, Northfield, Minnesota; Dr. Max Demorest, Department of Geology, Yale University, New Haven, Connecticut; François E. Matthes (Chairman), Senior Geologist, Section of Glacial Geology, United States Geological Survey, Washington, D.C.

Eos, Transactions, American Geophysical Union↗
USGS2013

Meeting the Science Needs of the Nation in the Wake of Hurricane Sandy-- A U.S. Geological Survey Science Plan for Support of Restoration and Recovery

n late October 2012, Hurricane Sandy came ashore during a spring high tide on the New Jersey coastline, delivering hurricane-force winds, storm tides exceeding 19 feet, driving rain, and plummeting temperatures. Hurricane Sandy resulted in 72 direct fatalities in the mid-Atlantic and northeastern United States, and widespread and substantial physical, environmental, ecological, social, and economic impacts estimated at near $50 billion. Before the landfall of Hurricane Sandy, the USGS provided forecasts of potential coastal change; collected oblique aerial photography of pre-storm coastal morphology; deployed storm-surge sensors, rapid-deployment streamgages, wave sensors, and barometric pressure sensors; conducted Light Detection And Ranging (lidar) aerial topographic surveys of coastal areas; and issued a landslide alert for landslide prone areas. During the storm, Tidal Telemetry Networks provided real-time water-level information along the coast. Long-term network and rapid-deployment real-time streamgages and water-quality monitors reported on river levels and changes in water quality. Immediately after the storm, the USGS serviced real-time instrumentation, retrieved data from over 140 storm-surge sensors, and collected other essential environmental data, including more than 830 high-water marks mapping the extent and elevation of the storm surge. Post-storm lidar surveys documented storm impacts to coastal barriers informing response and recovery and providing a new baseline to assess vulnerability of the reconfigured coast. The USGS Hazard Data Distribution System served storm related information from many agencies on the Internet on a daily basis. This science plan was developed immediately following Hurricane Sandy to coordinate continuing USGS activities with other agencies and to guide continued data collection and analysis to ensure support for recovery and restoration efforts. The data, information, and tools that are produced by implementing this plan will: (1) further characterize impacts and changes, (2) guide mitigation and restoration of impacted communities and ecosystems, (3) inform a redevelopment strategy aimed at developing resilient coastal communities and ecosystems, (4) improve preparedness and responsiveness to the next hurricane or similar coastal disaster, and (5) enable improved hazard assessment, response, and recovery for future storms along the hurricane prone shoreline of the United States. The activities outlined in this plan are organized in five themes based on impact types and information needs. These USGS science themes are: Theme 1: Coastal topography and bathymetry. Theme 2: Impacts to coastal beaches and barriers. Theme 3: Impacts of storm surge and estuarine and bay hydrology. Theme 4: Impacts on environmental quality and persisting contaminant exposures. Theme 5: Impacts to coastal ecosystems, habitats, and fish and wildlife. A major emphasis in the implementation of this plan will be on interacting with stakeholders to better understand their specific data and information needs, to define the best way to make information available, and to support applications of USGS science and expertise to decisionmaking.

Connecticut;Delaware;Maine;Maryl;Massachusetts;New↗
USGS1973

Geologic and hydrologic summary of salt domes in Gulf Coast region of Texas, Louisiana, Mississippi, and Alabama

There are 263 known or suspected onshore salt domes in the Texas-Louisiana-Mississippi-Alabama portion of the Gulf Coast geosyncline. The top of the salt in 148 of them is probably deeper than desirable for a waste repository site, and 79 of those that are shallow enough are probably unavailable for a site because of present use by industry for gas storage or production of oil, salt, or sulfur. In this report we have compiled the available geologic and hydrologic background data pertinent to the evaluation of the remaining 36 known or suspected salt domes as potential sites for waste storage. There are three parts to this compilations: 1) summaries of the geology and hydrology of the salt-dome province as a whole; 2) summaries of the physiography, climate, geology, and hydrology of each of the five salt-dome basins that occur within the province; and 3) an appendix of background data for each of the 36 potentially acceptable domes. The distribution of salt domes in the province is genetically related to areas of relative subsidence that formed basins or depocenters within the Gulf Coast geosyncline. In some cases, as in northeast Texas and south Louisiana, the locations of individual domes or groups of domes are related to deep movement of salt along axial trends. The salt domes in the interior salt-dome subprovince are probably more structurally stable than those of the coastal subprovince because salt diapirism is inferred to have ceased around Miocene time in the interior but may still be active in parts of the coastal subprovince. Although the size and shape of many domes is unknown or can only be roughly approximated, each of the five basins in the province appears to contain potentially acceptable domes of adequate size for a repository. We recognize no pattern to the distribution of salt-dome size. Caprock thicknesses vary greatly within each salt-dome basin,and we recognize no pattern to the variations. Among the potentially acceptable domes, the depths to the top of the salt are generally greatest in the Mississippi salt-dome basin, where all tops are more than 1,500 feet deep. Intermediate depths of about 1,000 feet are common in the east Texas-south Louisiana salt-dome basin. Depths to salt tops in the north Louisiana and northeast Texas basins are variable but most are less than 1,000 feet. Available drilling records are generally adequate to determine the number of wells drilled on or in the vicinity of individual domes and also the well locations. The numbers of wells vary widely within each salt-dome basin. More salt domes are currently available for use as repository sites in the interior subprovince than in the coastal subprovince, where the pressure for industrial use of domes is high. In the interior subprovince many of the potentially acceptable domes are located beneath hilly well-drained terrain that is not subject to flooding or other surface-water problems. Although topographic depressions occupied by shallow lakes, swamps, or 'salines' occur over several of the domes, they are generally flanked by topographically high ground where surface facilities could be sited without complications.A few of the potentially acceptable domes are located beneath floodplains where surface facilities might face hazards from flooding. In the coastal subprovince several of the potentially acceptable domes are located in relatively flat poorly drained terrain where surface flooding might constitute a potential hazard. The availability of fresh to slightly saline ground water varies considerably within each salt-dome basin. We have outlined some of the factors that are responsible for the variations and have provided or referred to maps and geohydrologic cross sections that illustrate the general distribution of fresh to slightly saline water. The top of the salt in about half of the known potentially acceptable domes is below the regional base of the fresh to slightly saline ground-water system, but in a few of

Alabama, Louisiana, Mississippi, Texas↗
USGS2017

Spatio-temporal mapping of plate boundary faults in California using geodetic imaging

The Pacific–North American plate boundary in California is composed of a 400-km-wide network of faults and zones of distributed deformation. Earthquakes, even large ones, can occur along individual or combinations of faults within the larger plate boundary system. While research often focuses on the primary and secondary faults, holistic study of the plate boundary is required to answer several fundamental questions. How do plate boundary motions partition across California faults? How do faults within the plate boundary interact during earthquakes? What fraction of strain accumulation is relieved aseismically and does this provide limits on fault rupture propagation? Geodetic imaging, broadly defined as measurement of crustal deformation and topography of the Earth’s surface, enables assessment of topographic characteristics and the spatio-temporal behavior of the Earth’s crust. We focus here on crustal deformation observed with continuous Global Positioning System (GPS) data and Interferometric Synthetic Aperture Radar (InSAR) from NASA’s airborne UAVSAR platform, and on high-resolution topography acquired from lidar and Structure from Motion (SfM) methods. Combined, these measurements are used to identify active structures, past ruptures, transient motions, and distribution of deformation. The observations inform estimates of the mechanical and geometric properties of faults. We discuss five areas in California as examples of different fault behavior, fault maturity and times within the earthquake cycle: the M6.0 2014 South Napa earthquake rupture, the San Jacinto fault, the creeping and locked Carrizo sections of the San Andreas fault, the Landers rupture in the Eastern California Shear Zone, and the convergence of the Eastern California Shear Zone and San Andreas fault in southern California. These examples indicate that distribution of crustal deformation can be measured using interferometric synthetic aperture radar (InSAR), Global Navigation Satellite System (GNSS), and high-resolution topography and can improve our understanding of tectonic deformation and rupture characteristics within the broad plate boundary zone.

California↗
USGS2001

Development of a seamless multisource topographic/bathymetric elevation model of Tampa Bay

Many applications of geospatial data in coastal environments require knowledge of the nearshore topography and bathymetry. However, because existing topographic and bathymetric data have been collected independently for different purposes, it has been difficult to use them together at the land/water interface owing to differences in format, projection, resolution, accuracy, and datums. As a first step toward solving the problems of integrating diverse coastal datasets, the U.S. Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA) are collaborating on a joint demonstration project to merge their data for the Tampa Bay region of Florida. The best available topographic and bathymetric data were extracted from the USGS National Elevation Dataset and the NOAA hydrographic survey database, respectively. Before being merged, the topographic and bathymetric datasets were processed with standard geographic information system tools to place them in a common horizontal reference frame. Also, a key part of the preprocessing was transformation to a common vertical reference through the use of VDatum, a new tool created by NOAA's National Geodetic Survey for vertical datum conversions. The final merged product is a seamless topographic/bathymetric model covering the Tampa Bay region at a grid spacing of 1 arc-second. Topographic LIDAR data were processed and merged with the bathymetry to demonstrate the incorporation of recent third party data sources for several test areas. A primary application of a merged topographic/bathymetric elevation model is for user-defined shoreline delineation, in which the user decides on the tidal condition (for example, low or high water) to be superimposed on the elevation data to determine the spatial position of the water line. Such a use of merged topographic/bathymetric data could lead to the development of a shoreline zone, which could reduce redundant mapping efforts by federal, state, and local agencies by allowing them to customize their portrayals of the shoreline using a standard baseline elevation dataset.

Marine Technology Society Journal↗
USGS2018

Bedrock mapping and seismic hazard assessment at Gold Basin landslide, Washington

The Gold Basin landslide is located along the South Fork Stillaguamish River, within the Mount Baker-Snoqualmie National Forest in western Washington State. Recent concerns related to slope stability after the 2014 State Route 530 Landslide near Oso, Washington, forced the closure of the U.S. Forest Service Gold Basin Campground in May of 2014. In addition to safety concerns for National Forest visitors, the landslide-derived sediment pulses shed into the South Fork Stillaguamish River may harm migrant salmon spawning grounds, an important resource for the Stillaguamish Tribe of Indians and for public anglers. The Gold Basin landslide is composed of three active lobes and has an approximate footprint of 566,560 m 2 . Each lobe consists of steep topographic escarpments contained largely within Pleistocene glacial outwash sediments and debris flow and earth flow deposits at the base. In addition to landslides confined within the Pleistocene glacial strata, bedrock landslides are also apparent on lidar imagery of the study area. Bedrock landslides may pose additional hazard to the area, either during stochastic hillslope failure or during strong ground motion events. Potential seismic sources include the proximal Darrington-Devils Mountain and southern Whidbey Island fault zones, as well as the offshore Cascadia Subduction Zone. Previous analyses of hillslope stability in the Cascade Range suggests that rock mass strength is a useful way of characterizing bedrock and fracture patterns in order to understand potential landslide-prone landscape. The goals of this investigation are to assess the glacial strata and bedrock geology of the Gold Basin landslide and adjacent areas and to assess how the geology and geomorphology within the study area affect the likelihood of coseismic landsliding.

Washington↗
USGS2005

The National Assessment of Shoreline Change: A GIS compilation of vector shorelines and associated shoreline change data for the U.S. southeast Atlantic coast

The Coastal and Marine Geology Program of the U.S. Geological Survey has generated a comprehensive database of digital vector shorelines and shoreline change rates for the U.S. Southeast Atlantic Coast (Florida, Georgia, South Carolina, North Carolina). These data, which are presented herein, were compiled as part of the U.S. Geological Survey's National Assessment of Shoreline Change Project. Beach erosion is a chronic problem along most open-ocean shores of the United States. As coastal populations continue to grow and community infrastructures are threatened by erosion, there is increased demand for accurate information including rates and trends of shoreline migration. There is also a critical need for shoreline change data that is consistent from one coastal region to another. One purpose of this work is to develop standard repeatable methods for mapping and analyzing shoreline movement so that periodic updates of shorelines and shoreline change rates can be made nationally that are systematic and internally consistent. This data compilation for open-ocean, sandy shorelines of the U.S. Southeast Atlantic Coast is the second in a series that already includes the Gulf of Mexico, and will eventually include the Pacific Coast, and parts of Hawaii and Alaska. Short- and long-term shoreline change evaluations are based on merging three historical shorelines with a modern shoreline derived from lidar (light detection and ranging) topographic surveys. Historical shorelines generally represent the following time periods: 1800s, 1920s-1930s, and 1970s. The most recent shoreline is derived from data collected over the period of 1997-2002. Long-term rates of change are calculated by linear regression using all four shorelines. Short-term rates of change are simple end-point rate calculations using the two most recent shorelines. Please refer to our full report on shoreline change for the U.S. Southeast Atlantic Coast at http://pubs.usgs.gov/of/2005/1401/ to get additional information regarding methods and results.

southeast Atlantic coast↗
USGS2007

Data collected to support monitoring of constructed emergent sandbar habitat on the Missouri River downstream from Gavins Point Dam, South Dakota and Nebraska, 2004-06

The U.S. Army Corps of Engineers has constructed emergent sandbar habitat on sections of the Missouri River bordering South Dakota and Nebraska downstream from Gavins Point Dam to create and enhance habitat for threatened and endangered bird species. Two areas near river miles 761.3 and 769.8 were selected for construction of emergent sandbar habitat. Pre- and postconstruction data were collected by the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, to evaluate the success of the habitat management techniques. Data collected include pre- and postconstruction channel-geometry data (bathymetric and topographic) for areas upstream from, downstream from, and within each construction site. Water-velocity data were collected for selected parts of the site near river mile 769.8. Instruments and methods used in data collection, as well as quality-assurance and quality-control measures, are described. Geospatial channel-geometry data are presented for transects of the river channel as cross sections and as geographical information system shapefiles. Geospatial land-surface elevation data are provided for part of each site in the form of a color-shaded relief map. Geospatial water-velocity data also are provided as color-shaded maps and geographical information system shapefiles.

Nebraska, South Dakota↗