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Geologic map of the Ferncliff and Louisa quadrangles, Louisa, Fluvanna, and Goochland Counties, Virginia Geologic map of the Ferncliff and Louisa quadrangles, Louisa, Fluvanna, and Goochland Counties, Virginia
The area encompassed by the geologic map of the Ferncliff and Louisa, Va., 7.5-minute quadrangles includes the hypothetical surface projection of the Quail fault, which is the subsurface fault that was responsible for the 2011 magnitude 5.8 (M5.8) Mineral, Va., earthquake. The mapping shows that the Quail fault appears to have reactivated the Harris Creek fault, a Paleozoic fault that...
Geologic map of the northern Harrat Rahat volcanic field, Kingdom of Saudi Arabia Geologic map of the northern Harrat Rahat volcanic field, Kingdom of Saudi Arabia
Harrat Rahat, in the west-central part of the Kingdom of Saudi Arabia, is the largest of 15 Cenozoic harrats (Arabic for “volcanic field”) distributed on the Arabian plate. It extends more than 300 km north-south and 50 to 75 km east-west, and it covers an area of approximately 20,000 km2, has a volume of approximately 2,000 km3, and encompasses more than 900 observable vents. Volcanism...
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map boundaries were drawn to cover all of the “Poncha...
Geostatistical estimation of the bottom altitude and thickness of the Mississippi River Valley alluvial aquifer Geostatistical estimation of the bottom altitude and thickness of the Mississippi River Valley alluvial aquifer
The Mississippi River Valley alluvial aquifer (MRVA) caps a shallow system of aquifers and confining units in the Mississippi Alluvial Plain (MAP) that extends across 45,000 square miles of the midwestern and southern United States from Illinois to Louisiana. Irrigation water from the MRVA is required to sustain extensive crop production, which has resulted in groundwater-level declines...
Groundwater-level change for the periods 2002–8, 2008–12, and 2008–16 in the Santa Fe Group aquifer system in the Albuquerque area, central New Mexico Groundwater-level change for the periods 2002–8, 2008–12, and 2008–16 in the Santa Fe Group aquifer system in the Albuquerque area, central New Mexico
The U.S. Geological Survey, in cooperation with the Albuquerque Bernalillo County Water Utility Authority (ABCWUA), has developed a series of maps and associated reports, beginning in 2002, that document groundwater levels in the production zone of the Santa Fe Group aquifer system beneath a large area of the City of Albuquerque, New Mexico (hereafter called the study area). Herein, we...
Historical land use and land cover for assessing the northern Colorado Front Range urban landscape Historical land use and land cover for assessing the northern Colorado Front Range urban landscape
We describe historical land-use and land-cover (LULC) maps for the northern Colorado urban Front Range. The Front Range urban landscape is diverse and interspersed with highly productive agriculture as well as natural land cover types including evergreen forest in the Rocky Mountain foothills and Great Plains grassland. To understand the dynamics of urban growth, raster maps were created...
Map of the approximate inland extent of saltwater at the base of the Biscayne aquifer in Miami-Dade County, Florida, 2018 Map of the approximate inland extent of saltwater at the base of the Biscayne aquifer in Miami-Dade County, Florida, 2018
The inland extent of saltwater at the base of the Biscayne aquifer in eastern Miami-Dade County, Florida, was mapped in 2011, and it was mapped in the Model Land Area in 2016. The saltwater interface has continued to move inland in some areas and is now near several active well fields. An updated approximation of the inland extent of saltwater has been created by using data collected...
Potentiometric surface of groundwater-level altitudes near the planned Highway 270 bypass, east of Hot Springs, Arkansas, July–August 2017 Potentiometric surface of groundwater-level altitudes near the planned Highway 270 bypass, east of Hot Springs, Arkansas, July–August 2017
The Ouachita Mountains aquifer system potentiometric-surface map is one component of the Hot Springs Bypass Groundwater Monitoring Project. The potentiometric-surface map provides a baseline assessment of shallow groundwater levels and flow directions before the construction of the Arkansas Department of Transportation planned extension of the Highway 270 bypass, east of Hot Springs...
Potentiometric surface of the Mississippi River Valley alluvial aquifer, spring 2016 Potentiometric surface of the Mississippi River Valley alluvial aquifer, spring 2016
A potentiometric surface map for spring 2016 was created for the Mississippi River Valley alluvial (MRVA) aquifer using selected available groundwater-altitude data from wells and surface-water-altitude data from streamgages. Most of the wells were measured annually or one time after installation, but some wells were measured more than one time or continually; streamgages are typically...
Sedimentation survey of Lago Guayabal, Villalba, Puerto Rico, December 2017 Sedimentation survey of Lago Guayabal, Villalba, Puerto Rico, December 2017
The U.S. Geological Survey, in cooperation with the Puerto Rico Electric Power Authority, conducted a sedimentation survey of Lago Guayabal in 2017 to determine reservoir infill sedimentation rates, generate a bathymetric map of the bottom elevations of the reservoir, and create a stage-volume relation. The original (1913) capacity of Lago Guayabal was 11.82 million cubic meters, and...
Stratigraphic and structural relations in trench exposures and geomorphology at the Big Burn, Lily Lake, and Lester Ranch sites, Bear River Fault Zone, Utah and Wyoming Stratigraphic and structural relations in trench exposures and geomorphology at the Big Burn, Lily Lake, and Lester Ranch sites, Bear River Fault Zone, Utah and Wyoming
This report provides trench photomosaics, logs and related site information, age data, and earthquake event evidence from three paleoseismic trench sites on the Bear River Fault Zone. Our motivation for studying the Bear River Fault Zone—a nascent normal fault in the Rocky Mountains east of the Basin and Range physiographic province—is twofold: (1) the intriguing conclusion from previous...