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Map Releases

Our programs produce accurate geologic maps and 3-D geologic frameworks that provide critical data for sustaining and improving the quality of life and economic vitality of the Nation. 

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Geologic map of the southern flank of Mauna Loa Volcano, Island of Hawai‘i, Hawaii

On the Island of Hawaiʻi, Mauna Loa, the largest volcano on Earth, has erupted 33 times since written descriptions became available in 1832. Some eruptions began with only brief seismic unrest, whereas others followed several months to a year of increased seismicity. Once underway, its eruptions can produce lava flows that may reach the sea in less than 24 hours, severing roads and utilities. In t

Potentiometric surface and hydrologic conditions of the South Coast aquifer, Santa Isabel area, Puerto Rico, March–April, 2014

A potentiometric surface map of the South Coast aquifer near Santa Isabel, Puerto Rico, was created from data collected during a synoptic survey of groundwater levels at 55 wells from March 31 to April 17, 2014. Measured groundwater level values ranged from −22.8 to 185.4 feet above mean sea level. During the study period, cumulative rainfall of 0.65 inch was recorded in the study area. Measuremen

Bedrock geologic map of the Mount Ascutney 7.5- x 15-minute quadrangle, Windsor County, Vermont, and Sullivan County, New Hampshire

The bedrock geology of the Mount Ascutney 7.5- x 15-minute quadrangle consists of highly deformed and metamorphosed Mesoproterozoic through Devonian metasedimentary and meta-igneous rocks intruded by rocks of the Mesozoic White Mountain Igneous Suite. In the west, Mesoproterozoic gneisses of the Mount Holly Complex are the oldest rocks and form the northeastern flank of the Chester dome. The alloc

Geologic map of the Homestake Reservoir 7.5′ quadrangle, Lake, Pitkin, and Eagle Counties, Colorado

The Homestake Reservoir 7.5' quadrangle lies at the northwestern end of the Upper Arkansas Valley, and headwaters of the Arkansas River, and the Roaring Fork, Fryingpan, and Eagle Rivers of the Colorado River system.  The quadrangle lies within tectonic provinces of the 1.4 giga-annum (Ga) Picuris orogeny and includes the late Paleozoic Ancestral Rockies, Late Cretaceous-Paleocene Laramide orogeny

Bathymetric survey and sedimentation analysis of Lago Carite, Puerto Rico, January 2018

During January 23–30, 2018, the U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, conducted a bathymetric survey of Lago Carite primarily to update estimates of the contemporary reservoir storage capacity and sedimentation rate. Previously designated transect lines were surveyed by using a depth sounder coupled to a differential Global Positioning System to gene

Geomorphological mapping and anthropogenic landform change in an urbanizing watershed using structure-from-motion photogrammetry and geospatial modeling techniques

Increasing urbanization and suburban growth in cities globally has highlighted the importance of land planning using detailed geomorphologic maps that depict anthropogenic landform changes. Such mapping provides information crucial for land management, hazard identification, and the management of the challenges arising from urbanization. The development and use of quantitative and repeatable metho

Hydrogeologic units, contour maps, and cross sections of the Boone and Roubidoux aquifers, northeastern Oklahoma, 2020

The Boone and Roubidoux aquifers (or their equivalents) are the main sources of fresh groundwater in northeastern Oklahoma. Projected total water demand of both surface water and groundwater in northeastern Oklahoma is expected to increase approximately 56 percent from 2010 to 2060. This report provides an overview of the hydrogeology of northeastern Oklahoma, with an emphasis on the hydrogeologic

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 (

Geologic map of Petroglyph National Monument and vicinity, Bernalillo County, New Mexico

This geologic map depicts and briefly describes geologic units underlying Petroglyph National Monument and immediately adjacent areas in Bernalillo County, New Mexico. The Monument is underlain dominantly by Quaternary basalts of the Albuquerque Volcanoes volcanic field, a series of basin-filling volcanic flows and associated vents from a monogenetic volcanic highland along the eastern margin of t

Seismicity of the Earth 1900–2018

This map illustrates 119 years of global seismicity in the context of global plate tectonics and the Earth’s physiography. Primarily designed for use by earth scientists, engineers, and educators, this map provides a comprehensive overview of strong (magnitude [M] 5.5 and larger) earthquakes since 1900. The map clearly identifies the locations of the “great” earthquakes (M 8.0 and larger) and the

High-resolution airborne geophysical survey of the Shellmound, Mississippi area

In late February to early March 2018, the U.S. Geological Survey acquired 2,364 line-kilometers (km) of airborne electromagnetic, magnetic, and radiometric data in the Shellmound, Mississippi study area. The purpose of this survey is to contribute high-resolution information about subsurface geologic structure to inform groundwater models, water resource infrastructure studies, and local decision

Geologic map of the Patrick quadrangle, Chesterfield County, South Carolina

The Patrick 7.5 minute quadrangle, located in Chesterfield County, South Carolina, lies entirely within the upper Atlantic Coastal Plain province. Directly to the southeast in the Dovesville quadrangle, the Pliocene Orangeburg Scarp marks the western edge of marine terraces that characterize the upper limit of the middle Atlantic Coastal Plain. The geologic mapping for this quadrangle was done fro