Maps

DiscussionThe winter rainy season of 2016–2017 brought abundant rainfall to the State of California and to the San Francisco Bay region. In January and February of 2017, intense rainfall from strong winter storms saturated soils in the region and triggered thousands of shallow landslides. The highest concentration of these landslides was in the eastern part of the bay region, where landslides in t

This three-dimensional (3D) geologic map displays the subsurface geology in the upper ~4 kilometers of the Earth’s crust in the southeastern Gabbs Valley geothermal area of west-central Nevada. The 3D map was constructed by integrating the results from detailed geologic mapping, 3D gravity inversion modeling, and potential-field-geophysical studies. This effort was undertaken as part of the Nevada

This report includes an updated geologic map and cross sections of the upper Santa Cruz River basin, southern Arizona. The map and cross sections describe the geometry, thickness, and structure of the Miocene to Holocene units which form the main aquifers in the basin. The report also includes results of new hydrogeologic studies including (1) mapping and defining depth to bedrock based on geophys

This 1:24,000-scale geologic map of the Silver Zone Pass quadrangle lies in the southern Toano Range in Elko County, Nevada. Metamorphic and sedimentary strata of the quadrangle range from Neoproterozoic to Permian in age. Important intrusions include the Late Jurassic (ca. 159 Ma) Silver Zone Pass pluton and Cretaceous Toano Spring pluton. In particular, the Silver Zone Pass pluton involves undef

This report presents digital geologic, gravity, and aeromagnetic maps for the onshore parts of the Santa Maria and Point Conception 30'x60' quadrangles at a compilation scale of 1:100,000. The map depicts the distribution of bedrock units, surficial deposits, paleontological data, geophysical data and structural features in the Santa Maria basin and the Santa Ynez Mountains to the south, an area c

The three-dimensional (3D) geologic map characterizes the subsurface in the Brady geothermal area in the northern Hot Springs Mountains of northwestern Nevada. We built the 3D map by integrating the results from detailed geologic mapping, seismic-reflection, potential-field-geophysical, and lithologic well-logging investigations completed in the study area. This effort was undertaken to investigat

Hinkley Valley, in the central to western Mojave Desert of southeastern California, has a long historical record owing to its position as a crossroads for rail and road traffic and its position adjacent to the Mojave River. Subflow in the Mojave River provided groundwater recharge that maintained water consumption and demand by way of shallow wells for local agriculture in the valley. Its crossroa

This geologic map includes a trove of stratigraphic and geomorphic information that chronicles the inception and evolution of the lower Colorado River. The map area is located near the south end of the Lake Mead National Recreation Area about 80 km (50 mi) downstream from Hoover Dam. It spans parts of northwestern Arizona and southern Nevada near the south end of Cottonwood Valley. The map include

The Portland-Vancouver-Hillsboro Metropolitan Area (metro area) has great scenic, natural, and cultural resources and is the major economic hub of Oregon. The metro area is subject to a variety of geologic hazards. Underthrusting of the oceanic plate along the Cascadia plate boundary fault, or megathrust, deforms the leading edge of North America and produces earthquakes on the megathrust and in t

Western Whatcom County has a rich history of glaciation, sea-level change, fluvial erosion and deposition, landsliding, nearby volcanic activity, and human landscape modification. This lidar-derived geomorphic map interprets this history from the form and position of the Earth’s surface.The geomorphic record is broken into nine phases, beginning with the peak of the Vashon stade of the Fraser glac

The geologic map of the Blythe 7.5' quadrangle spans about 60 percent of the width of the Holocene floodplain and valley floor of the lower Colorado River and the adjacent lower piedmont on the east side of the Colorado River Valley. This map depicts a composite geologic record of the river’s response to the transition from a natural flow regime to a strictly regulated one created by a series of u

The three-dimensional (3–D) geologic map characterizes the subsurface in the southern Carson Sink region. We created the 3–D map by integrating the results from seismic-reflection, potential-field-geophysical, and lithologic well-logging inves­tigations completed in and around the Fallon FORGE site as part of the U.S. Department of Energy Frontier Observatory for Research in Geothermal Energy (FOR