Unified Interior Regions

California

The Southwest Region includes California, Nevada, and Arizona. The Regional Office, headquartered in Sacramento, provides Center oversight and support, facilitates internal and external collaborations, and works to further USGS strategic science directions.

States L2 Landing Page Tabs

Filter Total Items: 393
Date published: December 19, 2018
Status: Completed

Quantification of Mercury Flux in Eroding Mining Debris, Yuba River Watershed, California

At two priority locations on BLM-administered land in the Yuba River watershed, the USGS has documented relatively rapid erosion of river bank material that consists of mercury (Hg)-laden sediment with a significant component of mining debris. 

Date published: December 19, 2018
Status: Completed

Shallow Aquifer Assessment Study for the Monterey Bay and Salinas Valley

High nitrate and trace element concentrations in groundwater represent a health threat to domestic well users. The concentrations and distributions of these constituents in shallow groundwater in the Salinas Valley of the central coast of California are poorly understood, and communities are concerned about the quality of their drinking water. 

Date published: December 19, 2018
Status: Completed

Relation of Groundwater Age to Herbicide Concentration Trends in Fresno and Tulare Counties, California

The California Department of Pesticide Regulation (DPR) has been monitoring pesticide concentrations in about 70 domestic drinking water wells located in vulnerable areas of Fresno and Tulare Counties for approximately 15 years. A recent analysis of the monitoring data indicated that there were decreases in simazine, diuron, and bromacil concentrations in many wells during 2000-2010.

Date published: December 19, 2018
Status: Completed

Determining Water Availability in the Russian River Watershed

The Russian River Watershed covers 1,500 square miles of urban, agricultural and forested lands in northern Sonoma County and southern Mendocino County, California. Communities in the Russian River Watershed (RRW) depend on a combination of Russian River water and groundwater to meet their water-supply demands. Water is used primarily for agricultural irrigation, municipal and private wells...

Contacts: Tracy Nishikawa
Date published: December 18, 2018
Status: Active

Water-Level, Water-Quality and Land-Subsidence Studies in the Mojave River and Morongo Groundwater Basins

Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. The population of the Mojave River and Morongo groundwater basins has grown rapidly during the last several decades, increasing from an estimated population of almost 273,000 in 1990 (...

Date published: December 18, 2018
Status: Completed

Pesticide Studies in the Sacramento/San Joaquin Delta and San Francisco Bay Estuary

The objectives of this specific study are to characterize the mixtures of current-use pesticides and pesticide degradates entering the Sacramento/San Joaquin Delta from its two main river sources over a period of 12 consecutive months. 

Contacts: James Orlando
Date published: December 17, 2018
Status: Completed

Delta sediment measurements to support numerical modeling of turbidity

The purpose of the proposed work is to collect data that will support the development, calibration, and validation of numerical models of sediment transport and turbidity in the Sacramento-San Joaquin Delta. 

Contacts: Scott A Wright
Date published: December 17, 2018
Status: Completed

Geomorphic Assessment and Restoration Alternatives Development for the Merced River in East Yosemite Valley, Yosemite National Park

The National Park Service (NPS) and USGS jointly will investigate impacts to the Merced River due to infrastructure and historic channel widening in east Yosemite Valley with a goal of constructing river management alternatives. Past management actions, such as gravel mining, channel riprap, and the construction of bridges that do not accommodate flood flows, have had long-lasting impacts to...

Contacts: Scott A Wright
Date published: December 14, 2018
Status: Completed

Assessing the Feasibility of Artificial Recharge and Storage and the Effectiveness and Sustainability of Insitu Arsenic Removal in the Antelope Valley, California

Project Update - 8/2/2011: Water having an arsenic concentration of 30 micrograms per liter was infiltrated from a test pond beginning in December, 2010. After water moved downward through the unsaturated zone, arsenic concentrations in ...

Contacts: Tracy Nishikawa
Date published: December 14, 2018
Status: Completed

Additional characterization of the impact of suction dredging, South Yuba River – Humbug Creek

The potential impacts of suction dredging on water quality remain largely undetermined, especially with regard to trace metals including Hg. Several State of California regulatory agencies have expressed concerns that suction dredging may cause deleterious impacts with regard to turbidity and Hg contamination in downstream areas.

Date published: December 14, 2018
Status: Completed

Determination of Mercury Loads for Cache Creek Settling Basin Inflow and Outflows and Related Investigations

Mercury (Hg), a legacy pollutant from mining of mercury deposits in the Coast Ranges as well as gold deposits in the Sierra Nevada, has contaminated surface waters throughout northern . Methylmercury (MeHg) is an organic form of Hg that bioaccumulates in food webs to elevated concentrations that threaten ecological health and human health through consumption of sport fish. 

Date published: December 14, 2018
Status: Completed

Statistical Evaluation of Factors Affecting Occurrence of Organic Constituents from Fuels in Public-Supply Wells in Southern California

Biofuels, including ethanol, are expected to provide a greater contribution to the fuel supply in the United States. Research in the past decade has shown that ethanol in gasoline can cause plumes of benzene in groundwater to be larger than they would otherwise be.

Filter Total Items: 519
Date published: July 22, 2019

California State Waters Map Series Data Catalog: Point Sur to Point Arguello Region

Each GIS data file is listed with a brief description, a small image, and links to the metadata files and the downloadable data files. The data were compiled in ArcMap. Raster data layers are registered TIFF images and are in the UTM Zone 10 coordinate system. Line features are in shapefile format and are projected in UTM Zone 10 coordinates.

Date published: July 1, 2019

Our Coast Our Future

Our Coast, Our Future (OCOF) is a collaborative, user-driven project focused on providing California coastal resource managers and planners locally relevant, online maps and tools to help understand, visualize, and anticipate vulnerabilities to sea level rise and storms.

Date published: June 11, 2019

Attributed California Water Supply Well Completion Report Data for Selected Areas, Derived from CA WCR OSCWR Data

This Well Completion Report geospatial dataset represents an index to a subset of records available from the California Department of Water Resources' (DWR) Online System for Well Completion Reports (OSWCR). This release contains water supply well records from Amador, Calaveras, El Dorado, Nevada, Placer, Sacramento, San Bernardino, Sutter, and Yuba counties. The USGS

Date published: May 16, 2019

USGS Installed Wells - San Diego County, CA

Summary tables of data for USGS installed wells in San Diego County, CA.  Included are links to data sets, including well construction, geophysical logs, lithologic logs, groundwater levels, water quality, and streamgages.

Date published: April 26, 2019

Furnished Data Guidelines

The annual review by USGS personnel of furnished records is designed to ensure that furnished records are collected in accordance with USGS standards. Furnished records are provided to the USGS by Federal Energy Regulatory Commission (FERC) licensees and other cooperating agencies as a method for reviewing and quality assuring their records so that the data are collected using methods that...

Date published: March 18, 2019

Topographic point clouds for the Mud Creek landslide, Big Sur, California from structure-from-motion photogrammetry from aerial photographs

This data release contains structure-from-motion (SfM) point-cloud data from aerial surveys conducted over the Mud Creek landslide on Big Sur from 1967-2018. Data sources include scanned aerial photographs, digital images collected from fixed-wing aircraft, and digital images collected from multirotor UAS.

Date published: February 21, 2019

Yucaipa Valley Hydrologic Monitoring

This site provides hydrologic data collected or compiled by the USGS in the Yucaipa area; some additional data may be available from the USGS database National Water Information System (NWIS).

Date published: February 13, 2019

San Antonio Creek Monitoring Networks

In order to understand the integrated hydrologic systems, many different types of data are being gathered from both the surface water and groundwater system. Learn about these data types and explore them with the interactive map.

Date published: February 11, 2019

Electromagnetic induction (EMI) geophysical data collected at the Bicycle Basin, U.S. Army Fort Irwin National Training Center, California

This data release presents raw (.csv) and processed (.csv) data files from land-based, frequency-domain electromagnetic induction (EMI) data collected at Bicycle Basin, U.S. Army Fort Irwin National Training Center, California. Data were collected during three distinct time periods: March 19, 2008 (1 survey), December 1 to December 5, 2014 (46 surveys) and Dece

Date published: February 1, 2019

Groundwater Levels and Water Quality | Borrego Valley

Table of groundwater well sites in the Borrego Valley that were sampled for groundwater quality and groundwater level measurements.  Provides links to data as well as archvied well documents.

Filter Total Items: 355
Publication Thumbnail
Year Published: 2015

Long‐term time‐dependent probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3)

The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model, published previously, renewal models are utilized to represent elastic-rebound-implied probabilities. A new...

Field, Edward H.; Biasi, Glenn P.; Bird, Peter; Dawson, Timothy E.; Felzer, Karen R.; Jackson, David A.; Johnson, Kaj M.; Jordan, Thomas H.; Madden, Christopher; Michael, Andrew J.; Milner, Kevin; Page, Morgan T.; Parsons, Thomas E.; Powers, Peter; Shaw, Bruce E.; Thatcher, Wayne R.; Weldon, Ray J.; Zeng, Yuehua
Field et al. (2015). Long-Term Time-Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3), Bulletin of the Seismological Society of America, Vol. 105, No. 2A, pp. 511–543, April 2015, doi: 10.1785/0120140093

Publication Thumbnail
Year Published: 2015

Predicting locations of post-fire debris-flow erosionin the San Gabriel Mountains of southern California

Timely hazard assessments are needed to assess post-fire debris flows that may impact communities located within and adjacent to recently burned areas. Implementing existing models for debris-flow probability and magnitude can be time-consuming because the geographic extent for applying the models is manually defined. In this study, a model is...

Gartner, Joseph E.; Santi, P.M; Cannon, Susan H.
Gartner, J.E., Santi, P.M., and Cannon, S.H. (2015), Predicting locations of post-fire debris-flow erosion in the San Gabriel Mountains of southern California, Natural Hazards, 77:1305–1321, DOI 10.1007/s11069-015-1656-3.

Publication Thumbnail
Year Published: 2015

Geologic map of the Bodie Hills, California and Nevada

The Bodie Hills covers about 1,200 km2 straddling the California-Nevada state boundary just north of Mono Lake in the western part of the Basin and Range Province, about 20 km east of the central Sierra Nevada. The area is mostly underlain by the partly overlapping, middle to late Miocene Bodie Hills volcanic field and Pliocene to late...

John, David A.; du Bray, Edward A.; Box, Stephen E.; Vikre, Peter G.; Rytuba, James J.; Fleck, Robert J.; Moring, Barry C.
John, D.A., du Bray, E.A., Box, S.E., Vikre, P.G., Rytuba, J.J., Fleck, R.J., and Moring, B.C., 2015, Geologic map of the Bodie Hills, California and Nevada: U.S. Geological Survey Scientific Investigations Map 3318, 64 p., 2 sheets, scale 1:50,000, http://dx.doi.org/10.3133/sim3318.

Publication Thumbnail
Year Published: 2015

“All Models Are Wrong, but Some Are Useful”

Building a new model, especially one used for policy purposes, takes considerable time, effort, and resources. In justifying such expenditures, one inevitably spends a lot of time denigrating previous models. For example, in pitching the third Uniform California Earthquake Rupture Forecast (UCERF3) (http://www.WGCEP.org/UCERF3), criticisms of the...

Field, Edward H.
Field, E. H. (2015). “All Models Are Wrong, but Some Are Useful”, Seismological Research Letters Volume 86, Number 2A March/April 2015, doi: 10.1785/02201401213

Publication Thumbnail
Year Published: 2015

Paleoseismologic evidence for large-magnitude (Mw 7.5-8.0) earthquakes on the Ventura blind thrust fault: Implications for multifault ruptures in the Transverse Ranges of southern California

Detailed analysis of continuously cored boreholes and cone penetrometer tests (CPTs), high-resolution seismic-reflection data, and luminescence and 14C dates from Holocene strata folded above the tip of the Ventura blind thrust fault constrain the ages and displacements of the two (or more) most recent earthquakes. These two earthquakes, which are...

McAuliffe, Lee J.; Dolan, James F.; Rhodes, Edward J.; Hubbard, Judith; Shaw, John H.; Pratt, Thomas L.
McAuliffe, L.J., Dolan, J.F., Rhodes, E.J., Hubbard, J., Shaw, J.H., and Pratt, T.L., 2015, Paleoseismologic evidence for large-magnitude (Mw≥7.5) earthquakes on the Ventura blind thrust fault: Implications for multi-fault ruptures in the Transverse Ranges of southern California, Geosphere, v. 11, no. 5, p. 1629-1650. doi:10.1130/GES01123.1

Publication Thumbnail
Year Published: 2014

Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California

Debris flows and sediment-laden floods in the Transverse Ranges of southern California pose severe hazards to nearby communities and infrastructure. Frequent wildfires denude hillslopes and increase the likelihood of these hazardous events. Debris-retention basins protect communities and infrastructure from the impacts of debris flows and sediment...

Gartner, Joseph E.; Cannon, Susan H.; Santi, Paul M
Gartner, J.E., Cannon, S.H., and Santi, P.M. (2014), Empirical models for predicting volumes of sediment deposited by debris flows and sediment-laden floods in the transverse ranges of southern California, Engineering Geology, 176, 24, Pages 45-56, 10.1016/j.enggeo.2014.04.008.

Publication Thumbnail
Year Published: 2014

Geodetic constraints on the 2014 M 6.0 South Napa earthquake

On 24 August 2014, the M 6.0 South Napa earthquake shook much of the San Francisco Bay area, leading to significant damage in the Napa Valley. The earthquake occurred in the vicinity of the West Napa fault (122.313° W, 38.22° N, 11.3 km), a mapped structure located between the Rodger’s Creek and Green Valley...

Barnhart, William D.; Murray, Jessica R.; Yun, S H; Svarc, Jerry L.; Samsonov, SV; Fielding, EJ; Brooks, Benjamin A.; Milillo, Pietro

Publication Thumbnail
Year Published: 2014

A VS30 map for California with geologic and topographic constraints

For many earthquake engineering applications, site response is estimated through empirical correlations with the time‐averaged shear‐wave velocity to 30 m depth (VS30). These applications therefore depend on the availability of either site‐specific VS30 measurements or VS30 maps at local, regional, and global scales....

Thompson, Eric; Wald, David J.; Worden, Charles
E. M. Thompson, D. J. Wald, and C. B. Worden (2014). A VS30 Map for California with Geologic and Topographic Constraints Bulletin of the Seismological Society of America 104, 2313-2321.

Publication Thumbnail
Year Published: 2014

Development of the Coastal Storm Modeling System (CoSMoS) for predicting the impact of storms on high-energy, active-margin coasts

The Coastal Storm Modeling System (CoSMoS) applies a predominantly deterministic framework to make detailed predictions (meter scale) of storm-induced coastal flooding, erosion, and cliff failures over large geographic scales (100s of kilometers). CoSMoS was developed for hindcast studies, operational applications (i.e., nowcasts and multiday...

Barnard, Patrick L.; van Ormondt, Maarten; Erikson, Li H.; Jodi Eshleman; Hapke, Cheryl J.; Peter Ruggiero; Peter Adams; Foxgrover, Amy C.
Barnard, Patrick L., van Ormondt, Maarten, Erikson, Li H., Eshleman, Jodi, Hapke, Cheryl, Ruggiero, Peter, Adams, Peter N., and Foxgrover, Amy C., 2014, Development of the Coastal Storm Modeling System (CoSMoS) for predicting the impact of storms on high-energy, active-margin coasts: Natural Hazards, v. 74, i. 2, pp. 1095-1125, doi:10.1007/s11069-014-1236-y

Publication Thumbnail
Year Published: 2014

Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California

Rock falls are common in Yosemite Valley, California, posing substantial hazard and risk to the approximately four million annual visitors to Yosemite National Park. Rock falls in Yosemite Valley over the past few decades have damaged structures and caused injuries within developed regions located on or adjacent to talus slopes highlighting the...

Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.
Quantitative rock-fall hazard and risk assessment for Yosemite Valley, Yosemite National Park, California; 2014; SIR; 2014-5129; Stock, Greg M.; Luco, Nicolas; Collins, Brian D.; Harp, Edwin L.; Reichenbach, Paola; Frankel, Kurt L.

Publication Thumbnail
Year Published: 2014

Sediment concentrations, flow conditions, and downstream evolution of two turbidity currents, Monterey Canyon, USA

The capacity of turbidity currents to carry sand and coarser sediment from shallow to deep regions in the submarine environment has attracted the attention of researchers from different disciplines. Yet not only are field measurements of oceanic turbidity currents a rare achievement, but also the data that have been collected consist mostly of...

Xu, Jingping; Octavio E. Sequeiros; Noble, Marlene A.
Xu, J.P., Sequeiros, O.E., Noble, M.A., 2014, Sediment concentrations, flow conditions, and downstream evolution of two turbidity currents, Monterey Canyon, USA: Deep Sea Research Part I: Oceanographic Research Papers, v. 89, pp. 11–34, doi: 10.1016/j.dsr.2014.04.001.

Publication Thumbnail
Year Published: 2014

Characterizing the primary material sources and dominant erosional processes for post-fire debris-flow initiation in a headwater basin using multi-temporal terrestrial laser scanning data

Wildfire dramatically alters the hydrologic response of a watershed such that even modest rainstorms can produce hazardous debris flows. Relative to shallow landslides, the primary sources of material and dominant erosional processes that contribute to post-fire debris-flow initiation are poorly constrained. Improving our understanding of how and...

Staley, Dennis M.; Waslewicz, Thad A.; Kean, Jason W.
Characterizing the primary material sources and dominant erosional processes for post-fire debris-flow initiation in a headwater basin using multi-temporal terrestrial laser scanning data; 2014; Article; Journal; Geomorphology; Staley, Dennis M.; Waslewicz, Thad A; Kean, Jason W.

Filter Total Items: 1,005
fault rupture
July 7, 2019

Searles Valley Earthquake field photo #9

Vertical fault rupture on road with truck.

fault scarp
July 6, 2019

Pointing out fault scarp for Searles Valley earthquake

USGS scientist pointing to the fault scarp that shows the fault moved horizontally, as well as laterally.

fault scarp
July 6, 2019

Fault scarp near epicenter of Searles Valley earthquake

Fault scarp close to the epicenter. In this location the fault has a main strand where much of the slip occurred, as well as distributed fractures.

nightly view of highway with large cracks from earthquake and car in the distance.
July 6, 2019

2019 Ridgecrest Earthquake Sequence - M7.1 Highway 178

Highway 178 SW of Trona. Taken earlier in the morning July 6, 2019 after the M7.1 earthquake which struck eastern California, southwest of Searles Valley, near Ridgecrest, CA.

Image shows two people standing on a desert rise
July 6, 2019

Inspecting the Fault Scarp

Scientists from USGS & CGS and Navy escort, and a UCLA engineer from the GEER team, inspect ~12 +/- 3 foot high fault scarp with from 3 to 5 feet of right-lateral motion near the expected maximum slip locality along the primary tectonic rupture associated with the M 7.1 event.

Image shows a road with damage from an earthquake
July 6, 2019

Damage to Access Road from Searles Valley Earthquake

Fault scarp at offset access road site. Center line has been offset up and to the right as one looks across the fault towards the east.

Image shows a group of people standing on a road surrounded by desert
July 6, 2019

Planning for Surveying for Earthquake Damage

Team discussion among CGS and USGS earthquake scientists at the location of the primary surface fault rupture where is has disrupted and offset an access road at the NAWS China Lake. The fault runs NW to SE across the road, which runs from west to east. The east side of the road is uplifted relative to the west side. The west side has shifted permanently towards the NW

...
Image shows an aerial view of a road with surrounding desert
July 6, 2019

Railroad Track Offsets from Searles Valley Earthquake

Railroad tracks offset right-laterally by about 3 feet; southeast of Hwy. 178.

Image shows an aerial view of desert
July 6, 2019

Right-Lateral Fractures from Searles Valley Earthquake

Right-lateral slip across fractures on a hillside, with shattered ground along the surface fault rupture near Ridgecrest, CA.

Image shows several people standing next to a helicopter
July 6, 2019

Preparing for a Helicopter Overflight

CGS and USGS geologists and geophysicists with National Guard and Navy personnel plan next phase of helicopter-supported field investigations on Sat., July 6, 2019 at China Lake NAWS.

Image shows several people standing on the desert
July 6, 2019

Preparing to Survey Searles Earthquake Scarp

USGS scientists and partners review objectives and group assignments  at fault scarp site. The team will deploy seismic instruments to better observe aftershock activity from close in, and to document surface faulting.

Image shows people silhouetted by the sun working in the desert
July 6, 2019

Surveying the Searles Valley Earthquake Scarp

USGS Seismologists Alan Yong and Elizabeth Cohcran conduct field work near the main rupture between Trona and Ridgecrest California.

Filter Total Items: 938
Cutout view of Mud Creek landslide area
June 1, 2017

USGS scientists analyzing before-and-after air photos have calculated the size of the May 20 landslide on California’s Big Sur coast, about 140 miles south of San Francisco. 

Mud Creek topographic point cloud Oblique Perspective
May 27, 2017

USGS is collecting and analyzing air photos to help monitor a huge landslide that occurred May 20 on California’s Big Sur coast.

An extremely rare Mojave River western pond turtle was recently observed in the Mojave Desert.
May 23, 2017

An extremely rare Mojave River western pond turtle was recently observed by U.S. Geological Survey scientists and staff from The Living Desert Zoo and Gardens in the Mojave Desert. Turtles of this population have rarely been seen since the late 1990s.

USGS
May 18, 2017

Members of the news media are invited to attend the next Earthquake Country Alliance - Bay Area Regional Workshop to be held at the U.S. Geological Survey in Menlo Park on May 23. ECA workshops are educational and informational opportunities to learn more about the latest in earthquake science, preparedness, and mitigation, as well as to arrange interviews with subject matter experts.

2014 South Napa Earthquake in California
May 15, 2017

Early on the morning of August 24, 2014, Loren Turner was awoken by clattering window blinds, a moving bed, and the sound of water splashing out of his backyard pool. He experienced what is now named the “South Napa Earthquake.” 

A radio-tracked adult desert tortoise basks in the sun among the wind turbines at a wind energy facility
May 3, 2017

How a wind energy facility is designed can influence the behavior of animal predators and their prey, according to a recent study published in The Journal of Wildlife Management by researchers at the University of California, Davis, and the U.S. Geological Survey.

Image shows a map of U.S. states colored based on the value of their mineral industry
April 14, 2017

In 2016, these five states led the pack in mineral production, accounting for about one third of the total mineral production value for the entire country.

BART
April 6, 2017

Although no one can reliably predict earthquakes, today’s technology is advanced enough to rapidly detect seismic waves as an earthquake begins, calculate the maximum expected shaking, and send alerts to surrounding areas before damage can occur. This technology is known as “earthquake early warning” (EEW).

Earthquake Early Warning: Vital for City Transit
April 6, 2017

The U.S. Geological Survey along with university, state and private-sector partners will highlight the rollout of Version 1.2 of the USGS ShakeAlert earthquake early warning system on April 10, 2017.

Field-trip guides to selected volcanoes and volcanic landscapes of ...
April 5, 2017

California is well-known for its frequent earthquakes, but less so for its volcanic history – despite the fact that the most recent eruption in the state occurred just 100 years ago.

CalVO geologists Duane Champion and Drew Downs collect paleomagneti...
April 3, 2017

New research on the ages of the most recent lava flows at Eagle Lake Volcanic Field, California suggest they are much older than once thought, minimizing the possibility of future eruption.

Filter Total Items: 231