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

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At least 865 records · Page 48Linked to original sources
USGS2022

By land, air, and water — U.S. Geological Survey science supporting fish and wildlife migrations throughout North America

Countless species of animals—big game, birds, bats, insects, amphibians, reptiles, and fish—migrate to reach suitable habitats to feed, reproduce, and raise their young. Animal migrations developed over millennia commonly follow migration corridors—unique routes for each species—to move among seasonal habitats. Changes along those corridors, whether from human development (buildings, roads, dams) or from natural disturbances (for example, climate change, drought, fire, flooding, or invasive species), can make them harder to navigate. The U.S. Geological Survey’s Ecosystems Mission Area provides science that assists land managers in mapping, enhancing, protecting, and reconnecting migration corridors critical for diverse fish and wildlife populations that migrate, such as Odocoileus hemionus (mule deer) and Antilocapra americana (pronghorn), trout and salmon, salamanders, tortoises, bats, and Danaus plexippus (monarch butterflies).

North America↗
USGS2024

Precariously balanced rocks in northern New York and Vermont, U.S.A.: Ground-motion constraints and implications for fault sources

Precariously balanced rocks (PBRs) and other fragile geologic features have the potential to constrain the maximum intensity of earthquake ground shaking over millennia. Such constraints may be particularly useful in the eastern United States (U.S.), where few earthquake‐source faults are reliably identified, and moderate earthquakes can be felt at great distances due to low seismic attenuation. We describe five PBRs in northern New York and Vermont—a region of elevated seismic hazard associated with historical seismicity. These boulders appear to be among the most fragile PBRs in the region, based on reports from hobbyists. The PBRs are glacial erratics, best evidenced by glacial striations on bedrock pedestals. The pedestals themselves are locally high knobs, often situated on regionally high topography; this setting limits soil development and indicates that any outwash deposits were likely ephemeral. As a result, PBR ages can be reliably established by the retreat of the last continental ice sheet, ∼15–13 ka. To quantify the fragility of the PBRs, we surveyed them with ground‐based light detection and ranging and calculated geometric parameters from the point clouds, field observations, and seismic responses. Preliminary validation of the 2023 time‐independent U.S. National Seismic Hazard Model (NSHM) shows that the existence of PBRs is generally consistent with the median site‐specific hazard curves. Only the Blue Ridge Road site suggests a modest reduction in hazard. To visualize the ensemble of data, we mapped the minimum permissible distance to potential source faults around each PBR site as a function of source magnitude by using the ground‐motion models from the 2023 NSHM. Viewed in this manner, our data are consistent with potential M ∼6.5 earthquake‐source faults in many parts of the Lake Champlain Valley and northern Adirondack Mountains. Our work illustrates a potential pathway for better constraining earthquake‐source faults in regions of cryptic faults.

Bulletin of the Seismological Society of America↗
USGS2008

Sediment deposition, erosion, and bathymetric change in central San Francisco Bay: 1855-1979

Central San Francisco Bay is the hub of a dynamic estuarine system connecting the San Joaquin and Sacramento River Deltas, Suisun Bay, and San Pablo Bay to the Pacific Ocean and South San Francisco Bay. To understand the role that Central San Francisco Bay plays in sediment transport throughout the system, it is necessary to first determine historical changes in patterns of sediment deposition and erosion from both natural and anthropogenic forces. The first extensive hydrographic survey of Central San Francisco Bay was conducted in 1853 by the National Ocean Service (NOS) (formerly the United States Coast and Geodetic Survey (USCGS)). From 1894 to 1979, four additional surveys, composed of a total of approximately 700,000 bathymetric soundings, were collected within Central San Francisco Bay. Converting these soundings into accurate bathymetric models involved many steps. The soundings were either hand digitized directly from the original USCGS and NOS hydrographic sheets (H-sheets) or obtained digitally from the National Geophysical Data Center's (NGDC) Geophysical Data System (GEODAS) (National Geophysical Data Center, 1996). Soundings were supplemented with contours that were either taken directly from the H-sheets or added in by hand. Shorelines and marsh areas were obtained from topographic sheets. The digitized soundings, depth contours, shorelines, and marsh areas were entered into a geographic information system (GIS) and georeferenced to a common horizontal datum. Using surface modeling software, bathymetric grids with a horizontal resolution of 25 m were developed for each of the five hydrographic surveys. Before analyses of sediment deposition and erosion were conducted, interpolation bias was removed and all of the grids were converted to a common vertical datum. These bathymetric grids were then used to develop bathymetric change maps for subsequent survey periods and to determine long-term changes in deposition and erosion by calculating volumes and rates of net sediment change. Central San Francisco Bay experienced periods of both deposition and erosion, but overall experienced a net gain in sediment from 1855 to 1979 of approximately 42x10 6 m 3 (0.33x10 6 m 3 / yr). Over this same time period, 92 percent of the tidal marsh and 69 percent of the intertidal mudflats were lost as human activity increased and the shorefront was developed. During the first time period, from 1855 to 1895, Central San Francisco Bay was erosional, losing roughly 2x10 6 m 3 / yr of sediment. The next time period was depositional, with a net gain of approximately 3x10 6 m 3 / yr of sediment from 1895 to 1947. The last time period, from 1947 to 1979, was erosional again, losing roughly 2x10 6 m 3 / yr of sediment. Sedimentation patterns also varied spatially. The northern part of Central San Francisco Bay was depositional during all change periods while the eastern region alternated between erosional and depositional. Central San Francisco Bay sedimentation patterns have also been strongly impacted by anthropogenic activities, such as dredging and dredge disposal, borrow pits, and sand mining. For example, bathymetric change at a borrow pit created near Bay Farm Island sometime between the 1947 and 1979 surveys indicates roughly 25x10 6 m 3 of sediment was removed from the system

California↗
USGS1977

Large landslides, composed of megabreccia, interbedded in Miocene basin deposits, southeastern Arizona

The landslides in the Kearny and El Capitan Mountain quadrangles, Pinal and Gila Counties, Ariz., are tabular or lens like masses of megabreccia enclosed in Miocene basin deposits. The megabreccias within individual slide blocks are composed of pervasively brecciated Precambrian and younger formations that remain in normal stratigraphic sequence, indicating that each landslide moved as a fairly coherent mass. The megabreccias consist of fresh, mostly angular rock fragments in a comminuted matrix of the same composition as the fragments. The matrix ranges in amount from sparse to abundant. Where the matrix is sparse, the fragments fit tightly with little or no rotation. Locally fragments are rotated but not moved far; most units within a slide block are lithologically homogeneous. The Kearny landslides are conformably interbedded in steeply east-dipping playa and alluvial deposits. They form map units from a few tens of meters to nearly 4 km long and from less than 1 to 270 m wide. Narrow ridges expose sections through the landslides at about right angles to the direction of movement. The upper (proximal) ends have been eroded; the lower (distal) ends are buried. The El Capitan landslide dips very gently southward. Although partly dissected during erosion of the enclosing alluvial and lakebed deposits, its approximate original outline is still preserved. It forms a thin sheet, 5-15 m thick and at least 3.8 km long; the maximum outcrop width, near its distal end, is about 1.5 km. The Kearny landslides show little evidence of having exerted differential pressure on the underlying soft playa and alluvial deposits, and the contacts with the underlying sediments have little relief. The distal end of the El Capitan landslide, on the other hand, has considerable relief. As the landslide came to an abrupt stop, the end plowed into the underlying sediments, compressing them into fol9.s and forming sandstone dikes. The source of the El Capitan landslide is a well-defined amphitheater on the south side of El Capitan Mountain 1,500 to more than 3,000 m above and 1.5-3 km north of the proximal end of the landslide. The long distance traveled on a very gentle slope indicates that the El Capitan landslide had a very low coefficient of friction, similar to some modern and prehistoric avalanches. According to Shreve, they may have traveled on a thin lubricating layer of compressed air. The coefficient of friction of the Kearny landslides cannot be determined. However, the nonturbulent character of both the Kearny and El Capitan landslides indicates that they slid rather than flowed.

Professional Paper↗
USGS1994

Land use and land cover digital data

Computer tapes derived from land use and land cover (LULC) data and associated maps at scales of 1 :250,000 and 1: 100,000 are available from the U.S. Geological Survey. This data can be used alone or combined with a base map or other supplemental data for a variety of applications, using commercially available software. You can produce area summary statistics, select specific portions of a map to study or display single classifications, such as bodies of water. LULC and associated digital data offer convenient, accurate, flexible, and cost-effective access to users who are involved in environmental studies, land use planning, land management, or resource planning.

Fact Sheet↗
USGS2013

Species data: National inventory of range maps and distribution models

The Gap Analysis Project (GAP) produces data and tools that help meet critical national challenges such as biodiversity conservation, renewable energy development, climate change adaptation, and infrastructure investment. The GAP species data includes vertebrate range maps and distribution models for the continental United States, as well as Alaska, Hawaii, Puerto Rico, and U.S. Virgin Islands. The vertebrate species include amphibians, birds, mammals, and reptiles. Furthermore, data used to create the distribution models (for example, percent canopy cover, elevation, and so forth) also are available.

Fact Sheet↗
USGS2019

Landsat 9

Landsat 9 is a partnership between the National Aeronautics and Space Administration and the U.S. Geological Survey that will continue the Landsat program’s critical role of repeat global observations for monitoring, understanding, and managing Earth’s natural resources. Since 1972, Landsat data have provided a unique resource for those who work in agriculture, geology, forestry, regional planning, education, mapping, and global-change research. Landsat images have also proved invaluable to the International Charter: Space and Major Disasters, supporting emergency response and disaster relief to save lives. With the addition of Landsat 9, the Landsat program’s record of land imaging will be extended to over half a century.

Fact Sheet↗
USGS1954

Physical exploration for uranium during 1951 in the Silver Reef district, Washington County, Utah

During 1951 a joint exploration program of the most promising uraniferous areas in the Silver Reef district was made by the U.S. Geological Survey and the U.S. atomic Energy Commission. A U.S. Bureau of Mines drill crew, on contract to the Atomic Energy Commission, did 2,450 feet of diamond drilling under the geological supervision of the U.S. Geological Survey. The purpose of the drilling was to delineate broadly the favorable ground for commercial development of the uranium deposits. Ten drill holes were located around Pumpkin Point, which is the northeastern end of Buckeye Reef, to probe for extensions of small ore sheets mined on the Point in fine-grained sandstones of the Chinle formation. Three additional holes were located around Tecumseh Hill to probe for extensions of the small showings of uranium-bearing rocks of Buckeye Reef. Only one trace of uranium mineral was detected in the 13 drill holes by logging of drill cores, gamma-ray logging of the holes, and analysis of many core splits from favorable lithology. Extensive traversing with Geiger counters throughout the district and detailed geologic mapping of areas on Buckeye Reef and on East Reef indicate that the chances of discovering significant uranium deposits in the Silver Reef district are very poor, because of: highly variable lithology, closely faulted structure, and obliteration of the shallow uranium-bearing lenses by silver mining. Most of the available ore in the district was in the Pumpkin Point area and has been mined during 1950 to 1953. No ore reserves can be computed for the district before further development work. The most favorable remaining area in the district is now being explored by the operators with Atomic Energy Commission supervision.

Open-File Report↗
USGS1992

Cartographic applications software

The Office of the Assistant Division Chief for Research, National Mapping Division, develops computer software for the solution of geometronic problems in the fields of surveying, geodesy, remote sensing, and photogrammetry. Software that has been developed using public funds is available on request for a nominal charge to recover the cost of duplication.

Fact Sheet↗
USGS2004

The U.S. Geological Survey Library

Established in 1879, to build and organize a collection of scientific materials in the earth sciences, the U.S. Geological Survey (USGS) Library is the largest earth sciences collection in the world. The USGS Library System is managed by the Geographic Information Office (GIO), Information Policy and Services Office, and includes four libraries in Reston, Va., Denver, Colo., Menlo Park, Calif., and Flagstaff, Ariz. The library holds over one million books and journals, 700,000 maps, 370,000 microforms, 270,000 pamphlets, and 250,000 photographs. In addition to the four libraries managed by the GIO, the USGS has smaller libraries in other locations with collections closely related to the specialized research of their local USGS scientists. The USGS Library System supports the research of USGS scientists by providing access to worldwide information resources. While continuing to build and maintain the large collections of maps, books, and periodicals, the USGS Library system is evolving from a traditional library to a more "virtual library." USGS employees, wherever they are located, have desktop access to an increasing wealth of electronic resources 24 hours a day, 7 days a week.

Fact Sheet↗
USGS2021

3D Elevation Program supports broadband internet access

According to the Federal Communications Commission, millions of Americans in rural parts of the country currently lack access to broadband (high-speed, always-on internet). Federal and State agencies have launched initiatives to enhance broadband access in rural America. High-resolution light detection and ranging (lidar) data can play a role in improving maps of broadband accessibility and helping to strengthen the broadband communications network. Lidar underpins signal propagation analyses to determine where broadband signals from communication towers can and cannot reach across the landscape and can be used to determine optimal siting of new towers and cell stations to increase broadband coverage.

Fact Sheet↗
USGS1975

Perspective diagrams showing geochemical abundance of silver, lanthanum, molybdenum, nickel, vanadium, yttrium, and zinc in the Nabesna Quadrangle, Alaska

The seven perspective diagrams on this sheet show the distribution patterns of silver, lanthanum, molybdenum, nickel, vanadium, yttrium, and zinc in stream sediments in the Nabesna quadrangle. The diagrams portray the distribution and abundance of the elements and their relation to some of the geologic units (Richter, 1975) in easy-to-visualize, 3-dimensional perspective.

Alaska↗
USGS2011

Project plan-Surficial geologic mapping and hydrogeologic framework studies in the Greater Platte River Basins (Central Great Plains) in support of ecosystem and climate change research

The Greater Platte River Basin area spans a central part of the Midcontinent and Great Plains from the Rocky Mountains on the west to the Missouri River on the east, and is defined to include drainage areas of the Platte, Niobrara, and Republican Rivers, the Rainwater Basin, and other adjoining areas overlying the northern High Plains aquifer. The Greater Platte River Basin contains abundant surficial deposits that were sensitive to, or are reflective of, the climate under which they formed: deposits from multiple glaciations in the mountain headwaters of the North and South Platte Rivers and from continental ice sheets in eastern Nebraska; fluvial terraces (ranging from Tertiary to Holocene in age) along the rivers and streams; vast areas of eolian sand in the Nebraska Sand Hills and other dune fields (recording multiple episodes of dune activity); thick sequences of windblown silt (loess); and sediment deposited in numerous lakes and wetlands. In addition, the Greater Platte River Basin overlies and contributes surface water to the High Plains aquifer, a nationally important groundwater system that underlies parts of eight states and sustains one of the major agricultural areas of the United States. The area also provides critical nesting habitat for birds such as plovers and terns, and roosting habitat for cranes and other migratory birds that travel through the Central Flyway of North America. This broad area, containing fragile ecosystems that could be further threatened by changes in climate and land use, has been identified by the USGS and the University of Nebraska-Lincoln as a region where intensive collaborative research could lead to a better understanding of climate change and what might be done to adapt to or mitigate its adverse effects to ecosystems and to humans. The need for robust data on the geologic framework of ecosystems in the Greater Platte River Basin has been acknowledged in proceedings from the 2008 Climate Change Workshop and in draft reports by researchers developing a multidisciplinary science plan for the Greater Platte River Basin.

Open-File Report↗
USGS2024

Projected sea-level rise and high tide flooding at Big Cypress National Preserve, Florida

Introduction National parks and preserves in the South Atlantic-Gulf Region contain valuable coastal habitats such as tidal wetlands and mangrove forests, as well as irreplaceable historic buildings and archeological sites located in low-lying areas. These natural and cultural resources are vulnerable to accelerated sea-level rise and escalating high tide flooding events. Through a Natural Resources Preservation Program-funded project during 2021–23, the U.S. Geological Survey, in collaboration with the National Park Service, estimated the probability of inundation at Big Cypress National Preserve, Florida, and several other parks under various sea-level rise scenarios and contemporary high tide flooding thresholds. The maps produced for this effort can be used to assess potential habitat change and explore how infrastructure and cultural resources within the park may be exposed to future flooding-related hazards.

Florida↗
USGS2024

Projected sea-level rise and high tide flooding at Biscayne National Park, Florida

Introduction National parks and preserves in the South Atlantic-Gulf Region contain valuable coastal habitats such as tidal wetlands and mangrove forests, as well as irreplaceable historic buildings and archeological sites located in low-lying areas. These natural and cultural resources are vulnerable to accelerated sea-level rise and escalating high tide flooding events. Through a Natural Resources Preservation Program-funded project during 2021–23, the U.S. Geological Survey, in collaboration with the National Park Service, estimated the probability of inundation at Biscayne National Park, Florida, and several other parks under various sea-level rise scenarios and contemporary high tide flooding thresholds. The maps produced for this effort can be used to assess potential habitat change and explore how infrastructure and cultural resources within the park may be exposed to future flooding-related hazards.

Florida↗
USGS1948

Index to river surveys made by the United States Geological Survey and other agencies, revised to July 1, 1947

The descriptive list of surveys of rivers in the United States issued by the United States Geological Survey in 1926 as Water-Supply Paper 558 comprised surveys by the Geological Survey and other Federal bureaus and by State, semiofficial, and private agencies. Since then many additional river surveys, most of them now available in published sheets, have been completed by the Geological Survey, and four supplemental lists describing them have been issued in mimeographed form. The first supplement was compiled by B. E. Jones in 1934, the second by R. O. Helland and D. M. Paul in 1938, the third by R. O. Helland in 1940, and the fourth by L. L. Young and N. J. Tubbs in 1944. The present compilation adds to the preliminary index the material issued in the supplements and later information concerning revisions and availability of maps.

Conterminous United States↗
USGS1989

Hydrothermal discharge zones beneath massive sulfide deposits mapped in the Oman ophiolite

The area in the Oman ophiolite containing the volcanic-hosted Bayda and Aarja massive sulfide deposits exposes a cross section of ocean crust and reveals to an unprecedented extent the fossil zones of hydrothermal upwelling that fed these sea-floor deposits. The fossil discharge zones are elongate areas of alteration and mineralization characterized by numerous small (metres to tens of metres in length), linear, discontinuous gossans. The gossans result from oxidation of hydrothermal pyrite replacing primary igneous phases and filling voids and fractures in the altered host rocks. The two deposits have separate discharge zones that appear to be sub-sea-floor extensions of their stockworks. The Bayda zone extends through the volcanic section into the upper sheeted dike complex and is interpreted as having formed on the ridge crest above an axial magma chamber; the Aarja zone terminates against a plagiogranite pluton that intrudes the lower volcanic section and is thought to have formed after Bayda in an off-axis environment. Structural, stratigraphic, and compositional characteristics of the Bayda and Aarja massive sulfide bodies are consistent with this interpretation. The geometry of the discharge zones suggests that in both cases upfiow occurred in broad zones (at least 400-600 m wide) that were elongated along strike (i.e., parallel to the spreading axis).

Oman ophiolite↗
USGS1989

Variations in fluvial style in the Westwater Canyon Member, Morrison formation (Jurassic), San Juan basin, Colorado plateau

Techniques of architectural element analysis and lateral profiling have been applied to the fluvial Westwater Canyon Member of the Morrison Formation (Jurassic) in southern San Juan Basin. On a large scale, the sandstone-body architecture consists mainly of a series of tabular sandstone sheets 5–15 m thick and hundreds of meters wide, separated by thin fine-grained units. Internally these sheets contain lateral accretion surfaces and are cut by channels 10–20 m deep and at least 250 m wide. On a more detailed scale, interpretations made from large-scale photomosaics show a complex of architectural elements and bounding surfaces. Typical indicators of moderate- to high-sinuosity channels (lateral accretion deposits) coexist in the same outcrop with downstream-accreted macroform deposits that are typical of sand flats of low-sinuosity, multiple-channel rivers. Broad, deep channels with gently to steeply dipping margins were mapped in several of the outcrops by carefully tracing major bounding surfaces. Locally thick accumulations of plane-laminated and low-angle cross-laminated sandstone lithofacies suggest rapid flow, probably transitional to upper flow regime conditions. Such a depositional style is most typical of ephemeral rivers or those periodically undergoing major seasonal (or more erratic) stage fluctuations, an interpretation consistent with independent mineralogical evidence of aridity. Fining-upward sequences are rare in the project area, contrary to the descriptions of Campbell (1976). The humid alluvial fan model of Galloway (1978) cannot be substantiated and, similarly, the architectural model of Campbell (1976) requires major revision. Comparisons with the depositional architecture of the large Indian rivers, such as the Ganges and Brahmaputra, still seem reasonable, as originally proposed by Campbell (1976), although there is now convincing evidence for aridity and for major stage fluctuations, which differs both from those modern rivers and Campbell's interpretation.

Arizona, Colorado, New Mexico, Utah↗