Using ground-water geochemical analyses, and mathematical models, the factors affecting the quality of public water supply were identified as pumping schedule, screened interval, past land use within the recharge area, and natural geochemical conditions.
The electric power generation potential from identified geothermal systems is 9,057 Megawattselectric (MWe), distributed over 13 states. Undiscovered resources are estimated to provide an additional 30,033 MWe.
We estimated undiscovered, technically recoverable resources are 534 billion cubic feet of natural gas and 323 thousand barrels of natural gas liquids in this area using a geology-based assessment methodology.
The mean total volume of potential oil reserves that might be added in the nine fields using improved oil-recovery technologies was estimated to be about 6.5 billion barrels of oil.
Summary showing number of wells in each county for which water level measurements are available, with description of methodology and well numbering system.
Map of California showing the number of wells (by county) with available water-level or water-quality data for Water Year 2010, with descriptions of the data and instructions for obtaining them.
A geologic and oceanographic study of the waters and Continental Shelf of Gulf of the Farallones adjacent to the San Francisco Bay region. The results of the study provide a scientific basis to evaluate and monitor human impact on the marine environment.
Describes a national reconnaissance study of reproductive health in two species of fish across the US. More than 2,200 common carp and 650 largemouth bass were collected at 119 rivers and streams.
Explains why we are assessing water quality in shallow aquifers, what we are measuring, and how the results will be reported both to well owners and to the public.
What causes changes in the hydrology, the ecology and the water quality of the Sacramento-San Joaquin River Delta and the San Francisco Bay estuary? These studies help state and local agencies manage resources well.
Modeling effort that integrates a wide variety of geographic, hydrologic, agricultural, climatic, and biological information to help local land managers address resource use issues.
An explanation of toxic carbon dioxide emissions at Mammoth Mountain in Long Valley caldera, and a description of magmatic helium discharge at the Mammoth Mountain fumarole with photos, maps, and links to other studies.
Real-time and historic data from gaging stations for water and mudflow detection in the Mount St. Helens, WA vicinity with data tables and plots, interactive location map and station descriptions.
Information on earthquakes in central California and the San Francisco region with links to four types of field studies, deep seismic investigations, geotechnical investigations, shallow seismic imaging, and airborne geophysical surveys.
Historical gold mining has left this area susceptible to mercury contamination. Elevated concentrations of mercury in the fish are well documented here.
Locations for nine species of large constrictors, from published sources, along with monthly precipitation and average monthly temperature for those locations. Shapefiles for each snake species studied.
Links to research studies, conservation information, and general information on desert tortoises at the Western Ecological Research Center in Sacramento, California.
Detailed measurements of elevation help to understand the extent and severity of subsidence. Study asks if subsidence indicates the aquifer system is compacting temporarily or permanently, and are the changes human-induced or tectonic.
Online catalog of scientific reports and data around and about Monterey Bay, California, indexed by author, agency, project, location, feature type, and topic
Collects a series of short articles on earthquake science and related topics for students, teachers, and parents originally published as weekly features in The San Francisco Chronicle.
Chart showing 13 volcanoes on a map of Washington, Oregon, and northern California, along with time lines for each volcano showing the ages of their eruptions.
Map of Pleistocene pluvial lakes in the western Great Basin (Nevada, eastern California, southern Oregon). Includes metadata, online PDF map view, and downloadable ArcInfo export files, ArcView shapefiles, and TIFF files.
After the powerful earthquake of April 18, 1906, staff of the U.S. Geological Survey stationed in Sacramento and Berkeley brought help to the residents of devastated San Francisco, documented the effects of the quake, and investigated its causes.
Study of wildland fire history and fire ecology such as plants in the Sierra Nevada forests, California shrublands, the Mojave, and Sonoran deserts to develop management techniques that will reduce hazards.
Summaries of geologic projects in cooperation with the National Park Service including Grand Canyon National Park, Lake Mead National Recreation Area, Golden Gate National Recreation Area, Joshua Tree National Park, Yosemite National Park, and others.
Collection of six short papers related to the mercury geochemical society, the study of mercury in coal, concentrations in sediment, soil, water, and fish collected near mercury and gold mines, and volanic emissions of mercury.
Site has links to Mohave National Preserve: geologic field trips, geologic history, plate tectonics, rocks and minerals, geologic time, geologic maps, and glossary.
This digital map database represents the general distribution of the geology (bedrock and surficial deposits) in San Mateo County. Accompanying text file (*.txt or *.ps) provides current information on the geologic structure and stratigraphy.
Report examines what is known about the Nation's ground-water availability, and outlines a program of study to improve our understanding of ground-water availability in major aquifers across the Nation. With regional examples.
Consistent, historic, and up-to-date ground-water data, such as water levels collected at wells and springs, are available from the USGS National Water Information System as graphs, tables, or files to download.
A systematic presentation of climatic and hydrogeologic framework of the area, regional analysis of ground-water recharge, and an overview of 8 site-specific case studies.
Arsenic was the trace element most frequently present at high concentrations here. High concentrations of arsenic result from the interaction of groundwater with naturally occurring minerals.
Arsenic and nitrate are the constituents found most commonly at high concentrations in the primary aquifers. Arsenic comes from natural sources and is affected by pH and dissolved oxygen.
Five trace elements with human-health concerns were detected at high concentrations: arsenic, boron, fluoride, molybdenum, and strontium. Vanadium was present at moderate concentrations.
Trace elements were present at high concentrations in 32% of the primary aquifers here, and at moderate concentrations in 17%. Of particular interest are aluminum, arsenic, vanadium, boron, fluoride, chromium, lead, and molybdenum.
Recent study indicates that inorganic trace elements and radioactive constituents are more likely to be subjects of concern in this less-developed area than anthropogenic organic compounds.
The occurrence of solvents in the groundwater is not correlated with current overlying land use and human activities. Rather, the solvents are from legacy industrial uses, and it has taken decades for the groundwater to move to where it is now pumped.
Five trace elements with human-health concerns were detected at high concentrations: arsenic, boron, fluoride, molybdenum, and strontium. Chromium was detected at moderate concentrations.
Five trace elements with human-health concerns were detected at high concentrations: arsenic, boron, molybdenum, strontium, and vanadium. Chromium and fluoride were detected at moderate concentrations.
Uranium, arsenic, and nitrate were the inorganic constituents that were most frequently detected at high concentrations, mostly in shallower wells. High and moderate concentrations of arsenic were detected in deeper wells.
Results of a survey of contaminants in untreated groundwater in this area. Arsenic and boron were the two trace elements detected most frequently at concentrations greater than the benchmarks.
Six elements with human-health concerns were detected at high concentrations: arsenic, boron, fluoride, molybdenum, strontium, and vanadium. Lead was present at moderate concentrations.
This study of untreated groundwater indicates the number of samples in which inorganic or organic constituents occur in high or moderate in concentration. The study does not indicate significant problems in groundwater quality here.
Arsenic and boron were the trace elements that most frequently occurred at high concentrations. Fumigants (pesticides) were detected at high concentrations in 3% of the primary aquifers. Herbicides and insecticides were detected at low concentrations.
Vanadium and boron were detected at high and moderate concentrations in this area. High concentrations for these constituents were detected almost exclusively in samples collected in the Temecula Valley study area.
Organic solvents are the chief concern in this area, which has given rise to a systematic program of monitoring and water treatment. This study shows relatively recent results.
The constituent present at high concentrations in the greatest proportion of the primary aquifer system was TDS, which is an indicator of salinity. Perchlorate was also present at moderate concentration in 42% of samples.
This study of untreated groundwater indicates the number of samples in which inorganic or organic constituents occur in high or moderate in concentration. The study does not indicate significant problems in groundwater quality here.
Results of a survey of contaminants in untreated groundwater in this area. Arsenic and boron were the trace elements occurring most frequently at high concentrations.
Recent study indicating inorganic constituents as the primary items of concern in this area. Chemical and mineralogical compositions of the aquifer rocks probably explain variation among localities here.
Recent study encountered occasional high values of radioactive trace elements, but the water quality in this area as monitored compares favorably to more urban areas studied by the same group.
Recent study indicating nitrate and perchlorate are the primary inorganic constituents of interest here, coming from human activities such as agriculture.
Summary of chemical constituents of ground water that are of concern to human activity in this area. Arsenic is the constituent that occurs most frequently in high concentrations.
Using a geographic dataset of structures, with more than 5500 structures that were destroyed or damaged by wildfire since 2001, we identified the main contributors to property loss in two extensive, fire-prone regions in southern California.
Hydrologic monitoring data for Long Valley caldera, California, on springs, streams, wells, fumaroles, and precipitation to study the natural hydrologic variations and the response of the hydrologic system to volcanic and tectonic processes.
Links to research projects that will improve the ability to detect, monitor, and predict the effects of invasive species, including exotic animals, on native ecosystems of the Pacific Southwest (California, Nevada, Utah, and Arizona).
Description of earthquake that was felt in Joshua Tree region (1999) and links to earthquake summary, shaded relief map, aerial photos of the rupture zone, shaking intensity maps, damage reports, and seismograph network map.
Describes and provides several detiled examples of impacts of human-induced land subsidence resulting from the extraction of subsurface water, including aquifer-system compaction, drainage of organic soils, dissolution and collapse of susceptible rocks.
Estimates of change in major types of land use and land cover from 1973 to 2000 should help model potential future change as climate, population, public policy, and technology change.
Study of the probability of a major earthquake in San Francisco Bay region with colored map and links to relevant publications. Text also available in PDF format and graphic available in Illustrator or Photoshop format.
Field data and satellite images allow us to make a calibrated model of percent vegetation cover, which we can use to inform scientific investigations and land management efforts.
Geospatial analysis of factors affecting communities that are adjacent to Federal lands, especially those lands subject to varying public interest and visitation.
Near-real-time maps of location, ground motion, and shaking intensity of earthquakes in California and Nevada for the past hour, past day, and past week and links to other earthquake information.
Guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings.
Examples of the use of Satellite Interferometric Synthetic Aperture Radar to measure and map changes on the Earth's surface as an aid to understanding how ground-water pumping, hydrocarbon production, or other human activities cause land subsidence.
Describes the monitoring effort and provides real-time data of the current restless activity of the caldera, including earthquakes, ground deformation, and release of volcanic gas and plus link to volcano monitoring techniques.
This report presents geochemical data generated during mineral and environmental assessments for the Bureau of Land Management in northern Nevada, northeastern California, southeastern Oregon, and southwestern Idaho, along with metadata and maps.
The Coastal and Marine Geology Program of the U.S. Geological Survey (USGS) is conducting an analysis of historical shoreline changes along open-ocean sandy shores of the conterminous United States and parts of Alaska and Hawaii.
Distribution and characteristics of natural oil and gas seeps in California, including processes of formation and effects on the environment; with discussion of tar pits and asphaltum.
Part A of a complex report on the results of ROCK-EVAL and vitrinite reflectance analysis of a large sample base from more than 70 wells located in three oil-rich California petroleum basins in order to study the formation of oil deposits.
Part B of a complex report on the results of geochemical analysis of 75 shale samples from the Los Angeles, Ventura, and San Joaquin Basins to gather observations relevant to exploration regarding the formation of oil deposits in these basins.
Overview of studies of fragile and active landscape of the American Southwest deserts, including projects on geologic mapping, surface processes, remote sensing research, ecological processes, and earthquake hazard applications.
Selection of photographic images of the Long Valley area that illustrate the consequences of the past geologic history of the Sierra Nevada, Long Valley Caldera, the Mono-Inyo Craters volcanic chain, glaciation, and faulting.
An introduction to the volcano hazards in the Long Valley area based on the past geologic history of the Long Valley Caldera and the Mono-Inyo Craters volcanic chain.
If you live or work in the San Francisco Bay region, this handbook explains why you should be concerned with earthquakes, what you can expect during and after a quake, and what you need to do beforehand to be safe and reduce property damage.
Consistent, real-time water data from streams, lakes, reservoirs, ground-water, and meteorological sites, are available from the USGS National Water Information System as graphs, tables, or files to download.
We estimated between 3.2 and 5.6 billion barrels of additional oil may be recovered with existing technology in this area using a probabilistic geology-based assessment methodology.
Provides location-depth grids of bathymetry available for San Francisco Bay and tools for examining those grids. Data provided as GIS grids and animations.
Description of 1998 drilling project at Long Valley Exploratory Well located on Long Valley Caldera's resurgent dome to monitor changing conditions beneath the dome. (Document in PDF format.)
Report with preliminary sea floor map displaying submarine rock exposures found along the northern part of Monterey Bay National Marine Sanctuary, extent based on side-scan sonar records, seismic-reflection records, and underwater video.
Download digital geologic databases produced by the Southern California Areal Mapping Project (SCAMP) or view SCAMP work in progress by clicking on 1:100,000-scale, 30x60 minute quadrangles.
Description of the SCAMP project to produce geologic and geophysical maps and reports that describe the geologic setting and geologic history of southern California.
Study of the susceptibility and vulnerability of basin-fill aquifers in the region to ground-water contamination by synthesizing the information on ground-water quality conditions in 15 basins from previous studies.
Change in streams accompanying land and water use may affect benthic invertebrate assemblage composition and structure through changes in density of invertebrates or taxa richness, the number of different species living in the stream.
A broad survey of regional patterns in stream flow nationwide. Maps and graphs summarizing streamflow conditions for water-year 2007 (October 1, 2006 to September 30, 2007) in the context of the 78-year period 1930-2007.
A broad survey of regional patterns in stream flow nationwide. Maps and graphs summarizing streamflow conditions for water-year 0810 (October 1, 2007 to September 30, 2008) in the context of the 79-year period 1930-2008.
A broad survey of regional patterns in stream flow nationwide. Maps and graphs summarizing streamflow conditions for water-year 2009 (October 1, 2008 to September 30, 2000) in the context of the 80-year period 1930-2009.
A broad survey of regional patterns in stream flow nationwide. Maps and graphs summarizing streamflow conditions for water-year 2010 (October 1, 2009 to September 30, 2010) in the context of the 81-year period 1930-2010.
A broad survey of regional patterns in stream flow nationwide. Maps and graphs summarizing streamflow conditions for water-year 2011 (October 1, 2010 to September 30, 2011) in the context of the 82-year period 1930-2011.
Suspended-sediment concentration data were collected in San Francisco Bay during water year 2000 using optical backscatterance sensors and water samples. This report presents the data-collection methods, data, and calibration plots.
Consistent, historic, and up-to-date surface-water data, such as gage height (stage) and streamflow (discharge), collected at major rivers, lakes, and reservoirs, downloadable from the USGS National Water Information System as graphs, tables, or files.
This publication (Open-File Report 95-479) is a teacher's guide to two U.S. Geological Survey maps that show gravity and magnetic data in contour form superimposed on a LANDSAT satellite image of the San Francisco Bay area.
Preparing for earthquakes along this important fault requires studying the history of its movement and its geology, as well as understanding how society has built the area around it.
Fact sheet describing plans for a San Andreas Fault Observatory at Depth (SAFOD) by drilling into the fault to install instruments for long-term monitoring near the location of the magnitude 6 Parkfield earthquakes.
Explains the characteristics and history of this distinctive way of describing geographic position characteristic of the midwestern and western states of the US.
Online booklet on the San Andreas fault system on the California coastal region with discussion of faults, relationship of faults and earthquakes, magnitude of earthquakes, and earthquake probability.
Annotated list of resources about the great earthquake of 1906, which caused significant devastation in and around San Francisco, California, compiled for the 100th anniversary of the disaster.
Techniques of computer-based representations of areal geology to construct three-dimensional geologic maps that retain all the information of traditional geologic maps while providing a more detailed picture of the subsurface.
Guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings.
Guidelines for correct tsunami response and community preparedness from local emergency managers, first-responders, and leading experts on tsunami hazards and warnings.
This updated subset of USGS streamgages for which the streamflow primarily reflects prevailing meteorological conditions for specified years, screened to exclude sites where human activity affects the natural flow of the watercourse.
Listing of USGS research and monitoring projects on mine drainage, in order to promote cooperation and collaboration among scientists working on problems related to mining and the environment.
The Sacramento-San Joaquin River Delta is the hub of California's water system and an important habitat for fish and wildlife. USGS research has provided resource managers and other stakeholders with a good understanding of how pesticides enter the Delta.
This endangered species prefers native trees in large, continuous areas of riparian habitat. Armed with this information, resource managers may identify and preserve areas favorable to this population.
We use moderate resolution satellite data to assess live fuel condition for estimating fire danger. Using 23 years of vegetation condition measurements, we are able to determine the relative greenness of wildland vegetation susceptible to burning.
Overview of volcano hazards in California with links to monitoring data including earthquakes and deformations, long-term outlook, volcano hazards in the area, USGS response plan, image gallery, monitoring and topical studies, publications and references.
Thirty year database of water-quality data, visual data displays, and project information on the San Francisco Bay directed towards following and understanding changes in the water quality of San Francisco Bay.