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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 523 records · Page 29Linked to original sources
USGS2018

Hydrographic surveys of rivers and lakes using a multibeam echosounder mapping system

A multibeam echosounder is a type of sound navigation and ranging device that uses sound waves to “see” through even murky waters. Unlike a single beam echosounder (also known as a depth sounder or fathometer) that releases a single sound pulse in a single, narrow beam and “listens” for the return echo, a multibeam system emits a multidirectional radial beam to obtain information within a fan-shaped swath. The timing and direction of the returning sound waves provide detailed information on the depth of water and the shape of the river channel, lake bottom, or any underwater features of interest. This information has been used by the U.S. Geological Survey to efficiently generate high-resolution maps of river and lake bottoms.

Missouri↗
USGS2021

South Dakota and Landsat

Few States derive as much of their social and economic well-being from the land as South Dakota. Agriculture is the State’s primary industry. Hunting, fishing, tourism, mining, and hydroelectric power are also important economic and cultural drivers. Data from the U.S. Geological Survey Landsat program, archived at the U.S. Geological Survey Earth Resources Observation and Science Center just outside Sioux Falls, South Dakota, has long been a boon to the monitoring, mapping, and management of the State’s land resources.

South Dakota↗
USGS2023

Flood warning toolset for the Sabinal River near Utopia, Texas

Introduction Floods are one of the most frequent and expensive natural disasters that occur across the United States. Rapid, high-water events that occur in local areas—flash floods—are especially difficult for emergency managers to predict and provide advance warning to the public, and insufficient data can hamper postflood recovery efforts. Central Texas is hilly, and it is known as a “flash flood alley” because of its high-intensity rains, shallow soils, and steep terrain, all of which combined can result in loss of life and property damage. For example, the flash flood event during July 2002 claimed 12 lives in central Texas, including 1 in the town of Utopia, which is on the east bank of the Sabinal River in a flash-flood-prone area along the Balcones Escarpment. During the flood event, the peak discharge recorded on July 5, 2002, at U.S. Geological Survey (USGS) streamgage 08198000 Sabinal River near Sabinal, Tex. (hereinafter referred to as the “Sabinal gage”), was 108,000 cubic feet per second (corresponding to a stream stage [also called gage height] of 33.74 feet). To put the 2002 flood into context, during a typical year the median daily discharge in the Sabinal River at the Sabinal gage is only about 23 cubic feet per second. In 2021, the USGS, in cooperation with the Bandera County River Authority and Groundwater District and the Texas Water Development Board, developed a flood warning toolset for the Sabinal River near Utopia. This study builds on earlier USGS flood work on the Medina River in Bandera County. The newly developed toolset consists of a newly installed USGS streamgage to collect continuous stream stage data (streamgage 08197970 Sabinal River at Utopia, Tex.; hereinafter referred to as the “Utopia gage”) 13 miles upstream from the Sabinal gage, a hydraulic model developed for the Sabinal River near Utopia, and an online library of digital flood-inundation maps referenced to the stream stage at the Utopia gage.

Texas↗
USGS2026

Bascom Laser Diffraction Sedimentology Laboratory, Reston, Virginia

Introduction At the Bascom Laser Diffraction Sedimentology Laboratory, which is located in the Florence Bascom Geoscience Center at U.S. Geological Survey (USGS) headquarters in Reston, Virginia, scientists use physical sedimentology and particle characterization techniques to conduct detailed sediment characterization. Scientists address research problems in collaboration with other USGS science centers, State geological surveys, commercial industry, universities, and other partners. Laboratory capabilities include laser diffractometry for quantitative particle-size analysis, portable x-ray fluorescence (XRF) analysis for determining elemental abundances in rock or sediment samples, petrographic analysis of geologic media, and mechanical sieve analysis. These methods are used to analyze soil and sediment core material from terrestrial, marine, and lacustrine environments, surface sediments from coastal regions, and calcareous materials. Work done by the laboratory supports geologic mapping, resource assessments, land change studies, and geohazard analyses.

Fact Sheet↗
USGS2017

Evidence from Lake Baikal for Siberian glaciation during oxygen-isotope substage 5d

The paleoclimatic record from bottom sediments of Lake Baikal (eastern Siberia) reveals new evidence for an abrupt and intense glaciation during the initial part of the last interglacial period (isotope substage 5d). This glaciation lasted about 12 000 yr from 117 000 to 105 000 yr BP according to correlation with the SPEC-MAP isotope chronology. Lithological and biogeochemical evidence of glaciation from Lake Baikal agrees with evidence for the advance of ice sheet in northwestern Siberia during this time period and also with cryogenic features within the strata of Kazantzevo soils in Southern Siberia. The severe 5d glaciation in Siberia was caused by dramatic cooling due to the decrease in solar insolation (as predicted by the model of insulation changes for northern Asia according to Milankovich theory) coupled with western atmospheric transport of moisture from the opea areas of Northern Atlantic and Arctic seas (which became ice-free due to the intense warming during preceeding isotope substage 5e). Other marine and continental records show evidence for cooling during 5d, but not for intense glaciation. Late Pleistocene glaciations in the Northern Hemisphere may have begun in northwestern Siberia.

Lake Baikal↗
USGS2014

Regional seismic lines across the Rome trough and Allegheny Plateau of northern West Virginia, western Maryland, and southwestern West Virginia

This chapter is a re-release of U.S. Geological Survey Geologic Investigations Map I–2791, of the same title, by Kulander and Ryder (2005), which in printed form consists of two oversized sheets and an accompanying pamphlet. The digital version of this publication, however, is only available as the pamphlet and a collection of all the individual graphics that are found on the two sheets.

Appalachian basin, Rome Trough↗
USGS1993

Altitude and configuration of the potentiometric surfaces of the upper and lower aquifer systems in Bridgeton, Nockamixon, and Tinicum Townships, Bucks County, Pennsylvania, April 1991 through April 1992

The mapped area in underlain by layered sedimentary rocks chiefly consisting of shale, mudstone, siltstone, and argillite and by a diabase sheet thtat has intruded the sedimentary rocks. The sedimentary rocks adjacent to the diabase are thermally altered to hornfels. Water levels in shallow wells completed in the diabase indicate the presence of an upper, shallow aquifer system.

Pennslyvania↗
USGS2018

Brackish groundwater and its potential as a resource in the southwestern United States

Secure, reliable, and sustainable water resources are fundamental to food production, energy independence, and the health of humans and ecosystems. But the large-scale development of fresh groundwater resources has stressed aquifers in some areas, causing declines in the amount of groundwater in storage and decreases in discharge to surface-water bodies like rivers and springs (Reilly and others, 2008). In some parts of the southwestern United States, the water supply is not adequate to meet demand without substantial effects on groundwater storage or surface discharge, and severe drought intensifies the stresses affecting water resources. In support of the national census of water resources, the U.S. Geological Survey (USGS) completed the national brackish groundwater assessment to provide information about brackish groundwater as a potential resource to augment or replace freshwater supplies (Stanton and others, 2017). The objectives of the brackish groundwater assessment were to consolidate available data into a comprehensive database of brackish groundwater resources in the United States and to produce a summary report about the distribution, physical and chemical characteristics, and use of brackish groundwater. This fact sheet summarizes the occurrence of brackish groundwater and factors affecting its usability in the southwestern United States (specifically the Southwest Basins region) reported for the national study. The map below (fig. 1) summarizes the brackish zones for the five largest principal aquifers within the southwestern United States, along with groundwater resources in the remaining part of the region (Reilly and others, 2008).

Fact Sheet↗
USGS2020

Geologic map of the Bonanza caldera area, northeastern San Juan Mountains, Colorado

The San Juan Mountains in southwestern Colorado have long been known as a site of exceptionally voluminous mid-Tertiary volcanism, including at least 22 major ignimbrite sheets (each 150–5,000 km³) and associated caldera structures active at 34–23 Ma. Recent volcanologic and petrologic studies in the San Juan region have focused mainly on several ignimbrite-caldera systems: the southeastern area (Platoro complex), western calderas (Uncompahgre-Silverton-Lake City), and the central cluster (La Garita-Creede calderas). Far less studied has been the northeastern San Juan region, which occupies a transition between earlier volcanism in central Colorado and large-volume younger ignimbrite-caldera foci farther south and west. This map is based on new field coverage of volcanic rocks in thirteen 7.5' quadrangles in northeastern parts of the volcanic field, high-resolution age determinations for 130 sites, and petrologic studies involving several hundred new chemical analyses. This mapping and the accompanying lab results (1) document volcanic evolution of the deeply eroded Bonanza caldera that exposes unique features not previously described from ignimbrite calderas elsewhere, as well as the previously unstudied Marshall Pass caldera; (2) provide unique cross-sectional exposures of the steeply resurgent Bonanza caldera, from volcanic floor and underlying basement rocks through a complete 3.5-km-thick section of intracaldera ignimbrite and overlying compositionally diverse caldera-filling lavas; (3) document timing of caldera collapse concurrently with eruption of about 1,000 km 3 of ignimbrite that oscillated in composition from mafic dacite to rhyolite; (4) quantify the regional time-space-volume progression from the earlier Sawatch magmatic trend southward into the San Juan region; and (5) permit more rigorous comparison between the broad mid-Tertiary magmatic belt in the western U.S. Cordillera and the type continental-margin arc volcanism of the central Andes in South America.

Scientific Investigations Map↗
USGS1967

Oligocene or younger thrust faulting in the Ruby Mountains, northeastern Nevada

A klippe of unmetamorphosed Devonian carbonate rocks rests on the Harrison Pass intrusive body south of Toyn Creek in the central Ruby Mountains , Elko County, Nevada . This klippe and other klippen of Carboniferous strata - first mapped by R. P. Sharp (1942) - that rest on lower Paleozoic strata are believed to represent a once-continuous thrust sheet that developed after emplacement of the intrusive body. This intrusion of coarse-grained granodiorite to quartz monzonite is exposed over an area of about 45 square miles. Potassium-argon and lead-alpha age determinations on four samples of the intrusive body establish Oligocene or younger age for the thrusting. Potassium-argon age determinations on biotites from the four samples range from 29 to 36 m.y. with a possible analytical error of ±10 percent. Lead-alpha age determinations (all with a possible analytical error of ±10 m.y.) on zircon showed 40 m.y. for three of the samples and 30 m.y. for the fourth. Lead-alpha and potassium-argon dates on a fifth sample collected by R. R. Coats also fall within these ranges. The agreement of the radiometric dates indicates a lack of thermal activity subsequent to the emplacement of the intrusion and establishes a maximum age of Oligocene for the thrust faulting . The present distribution of thermally metamorphosed Paleozoic rocks in the Ruby Mountains seems to preclude the possibility that the thrust plate originated within the Ruby Mountains . Sharp suggested a western source with displacement of from 7 to 10 miles.

Nevada↗
USGS1993

Digital orthophotos

A digital orthophoto is a digital image of an aerial photograph with displacements caused by the camera angle and the terrain removed. It, thus, combines the image characteristics of a photograph with the geometric qualities of a map.

Fact Sheet↗
USGS2000

Digital orthophoto quadrangles

A digital orthophoto quadrangle (DOQ) is a computer-generated image of an aerial photograph in which image displacement caused by terrain relief and camera tilts has been removed. It combines the image characteristics of a photograph with the geometric qualities of a map.

Fact Sheet↗
USGS1997

Revision and product generation software

The U.S. Geological Survey (USGS) developed revision and product generation (RevPG) software for updating digital line graph (DLG) data and producing maps from such data. This software is based on ARC/INFO, a geographic information system from Environmental Systems Resource Institute (ESRI). RevPG consists of ARC/INFO Arc Macro Language (AML) programs, C routines, and interface menus that permit operators to collect vector data using aerial images, to symbolize the data on-screen, and to produce plots and color-separated files for use in printing maps.

Fact Sheet↗
USGS2002

Spatial data available on the web at http://mrdata.usgs.gov/

Earth science information is important to decisionmakers who formulate public policy related to mineral resource sustainability, land stewardship, environmental hazards, the economy, and public health. To meet the growing demand for easily accessible data, the Mineral Resources Program has developed, in cooperation with other Federal and State agencies, an Internet-based, data-delivery system that allows interested customers worldwide to download accurate, up-to-date mineral resource-related data at any time. All data in the system are spatially located and customers with Internet access and a modern Web browser can easily produce maps having user-defined overlays for any region of interest.

Fact Sheet↗
USGS2002

Using maps in genealogy

In genealogical research, maps can provide clues to where our ancestors may have lived and where to look for written records about them. Beginners should master basic genealogical research techniques before starting to use topographic maps.

Fact Sheet↗
USGS2002

Cooperative Topographic Mapping Program

The mission of the Cooperative Topographic Mapping (CTM) Program of the U.S. Geological Survey (USGS) is to provide the Nation with access to current, accurate, and consistent base geographic data and derivative products, including topographic maps. The CTM Program has the lead responsibility to develop, maintain, and make available The National Map.

Fact Sheet↗
USGS2013

Quaternary geologic map of the Shelby 1° x 2° quadrangle, Montana

The Shelby quadrangle encompasses approximately 16,084 km 2 (6,210 mi 2 ). The northern boundary is the Montana/Saskatchewan (U.S./Canada) boundary. The quadrangle is in the Northern Plains physiographic province and it includes the Sweet Grass Hills. The primary river is the Marias River. The ancestral Missouri River was diverted south of the Bearpaw Mountains by a Laurentide ice sheet. The fill in the buried ancestral valleys of the Missouri River and Marias River in the southeast quarter of the quadrangle contains a complex stratigraphy of fluvial, glaciofluvial, ice-contact, glacial, lacustrine, and eolian deposits. The map units are surficial deposits and materials, not landforms. Deposits that comprise some constructional landforms (for example, ground-moraine deposits, end-moraine deposits, stagnation-moraine deposits, all composed of till) are distinguished for purposes of reconstruction of glacial history. Surficial deposits and materials are assigned to 21 map units on the basis of genesis, age, lithology or composition, texture or particle size, and other physical, chemical, and engineering characteristics. It is not a map of soils that are recognized in pedology or agronomy. Rather, it is a generalized map of soils recognized in engineering geology, or of substrata or parent materials in which pedologic or agronomic soils are formed. Glaciotectonic (ice-thrust) structures and deposits are mapped separately, represented by a symbol. On the glaciated plains, the surficial deposits are glacial, ice-contact, glaciofluvial, alluvial, lacustrine, eolian, colluvial, and mass-movement deposits. In the Sweet Grass Hills, beyond the limit of Quaternary glaciation they are fluvial, colluvial, and mass-movement deposits. Till of late Wisconsin age is represented by three map units. Tills of Illinoian and pre-Illinoian glaciations are not mapped, but are widespread in the subsurface. Linear ice-molded landforms (primarily drumlins) indicate directions of ice flow during late Wisconsin glaciation.

Montana↗