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: 418
Date published: October 30, 2017
Status: Active

Supporting Informed Responses to Sea-Level Rise

To facilitate communication and outreach of sea level rise research results and implications, Dr. Karen Thorne and members of USGS WERC are hosting in-person workshops along the Pacific coast at different sites in Washington, Oregon, and California.

Date published: October 30, 2017
Status: Active

California Sea Otter Stranding Network

The California Sea Otter Stranding Network is part of the USGS effort to monitor southern sea otters (Enhydra lutris nereis) and provide data to the U.S. Fish and Wildlife Service. WERC's sea otter team works with multiple institutions and partners to report, recover, and examine stranded sea otters. In addition, instructions on how to report a stranded sea otter are included in this webpage...

Date published: October 30, 2017
Status: Active

Process-based Approaches for Ecological Restoration of Degraded Drylands

Surface disturbances ranging from military training, recreation, energy exploration and development, and wildfires impact a large majority of federal lands in the western US, but the ecological and economic impacts are poorly understood. Explore this webpage to learn how Dr. Lesley DeFalco and her research team are currently evaluating and refining conventional approaches for post-fire...

Contacts: Lesley DeFalco
Date published: October 30, 2017
Status: Active

Native Plant Materials for Ecological Restoration of Degraded Drylands

There is a growing consensus among resource managers to use native plant materials for ecological restoration of degraded drylands. Some plant species may be suitable for re-introduction across broad environmental gradients. Other species may fail under narrower conditions, or their re-introduction may have genetic consequences for local ecotypes, particularly when adapting to future climate...

Contacts: Lesley DeFalco
Date published: October 30, 2017
Status: Active

Conservation of Rare, Sensitive, and At-risk Desert Plant Species

The Mojave Desert is among the hottest and driest of the North American drylands, but in spite of these extreme conditions, and in part because of them, a diverse flora exists. This diversity of rare, endemic, and endangered species is threatened by the complex interaction between fluctuating climate and human-mediated disturbances. USGS studies have identified rare species “hotspots” for...

Contacts: Lesley DeFalco
Date published: October 30, 2017
Status: Active

Wetland Restoration in the San Francisco Bay Delta and Pacific Northwest

Estuaries and healthy coastal habitats are among the most productive ecosystems on Earth. They provide a variety of benefits, including habitat and food for fish and wildlife, flood and erosion protection, improved water quality, increased carbon sequestration, as well as beautiful scenery and opportunities for recreation.  Along the U.S. Pacific Coast, both the San Francisco Bay estuary and...

Date published: October 30, 2017
Status: Active

Waterbird Breeding Ecology and Management

The San Francisco Bay is designated as a site of hemispheric importance to shorebirds and annually supports over one million waterbirds. Within the USGS WERC waterbird breeding ecology program, Dr. Josh Ackerman and partners are studying habitat selection, movements, and factors influencing waterbird nest success and chick growth and survival. 

Contacts: Josh T Ackerman
Date published: October 30, 2017
Status: Active

Contaminants in Waterbirds and Effects on Avian Reproduction

California’s Central Valley and San Francisco Bay Estuary have a long history of mercury contamination from past mercury mining and gold extraction. Waterbirds are particularly susceptible to mercury because of their use of wetland habitats where methylmercury (the most toxic and biologically available form) is produced and relatively low methylmercury exposure can reduce reproductive success...

Contacts: Josh T Ackerman
Date published: October 30, 2017
Status: Active

California Sea Otter Surveys and Research

WERC collaborates with other research scientists to conduct annual population surveys of the southern sea otter -- a federally listed threatened species. In coordination with the California Department of Fish and Game and other institutions, ongoing surveys and research continues to inform the southern sea otter recovery plan for the U.S. Fish and Wildlife Service, and contributes to our...

Date published: October 30, 2017
Status: Active

Mercury Bioaccumulation in Wetlands

Wetlands provide numerous ecosystem services, but also can be sources of methylmercury production and export. Click the next tab to learn how WERC's Dr. Josh Ackerman is evaluating the ecological factors that drive contaminant bioaccumulation in wetland-dependent fish and wildlife.

Contacts: Josh T Ackerman
Date published: October 30, 2017
Status: Active

Population Biology and Behavior of Sea Otters

WERC's sea otter researchers are developing and utilizing a variety of methodological and analytical tools to understand the causes of biological and ecological trends in sea otter populations, and to predict the ecological consequences of management practices on these populations and their ecosystems.

Date published: October 30, 2017
Status: Active

Waterfowl Ecology in California and the Pacific Flyway

The Suisun Marsh and Central Valley in California offer some of the world’s most important wetland habitats for waterfowl in the Pacific Flyway. Mike Casazza and USGS WERC biologists are providing the science to support and evaluate waterfowl populations and habitat management in North America.

Contacts: Michael Casazza
Filter Total Items: 577
Date published: November 30, 2018

Downloadable Data for Central Coastal Basin Oil and Gas Assessments

GIS Data for Central Coastal Basin Oil and Gas Assessments 

Date published: November 30, 2018

Downloadable Data for Sonoma-Livermore Basin Oil and Gas Assessments

GIS Data Sonoma-Livermore Basin Oil and Gas Assessments 

Date published: November 30, 2018

Downloadable Data for Northern Coastal Basin Oil and Gas Assessments

Northern Coastal Basin Oil and Gas Assessments

Date published: November 29, 2018

Downloadable Data for San Joaquin Basin Oil and Gas Assessments

Downloadable Data for San Joaquin Basin Oil and Gas Assessments

Date published: November 29, 2018

Downloadable Data for Sacramento Basin Oil and Gas Assessments

Downloadable Data for Sacramento Basin Oil and Gas Assessments

Date published: November 8, 2018

2010 Estimated California Water Use

Withdrawal estimates for each category represent the total amount of water removed from the water source, regardless of how much of that total is consumptively used. In most cases, some fraction of the total withdrawal will be returned to the same or a different water source after use and is available for other withdrawals.

Date published: October 29, 2018

California Seafloor Mapping Program progress

Table showing California Seafloor Mapping Program map block mapping progress by block number, as of April 2018.

Date published: October 25, 2018

Beach topography and nearshore bathymetry of northern Monterey Bay, California

This data release presents beach topography and nearshore bathymetry data from repeated surveys in northern Monterey Bay, California to document changes in shoreline position and coastal morphology as they relate to episodic (storms), seasonal, and interannual and longer processes. Since October 2014, semi-annual surveys have been performed in late summer (September or October...

Date published: October 22, 2018

Grain size, mineralogic, and trace-element data from field samples near Hinkley, California

This data release is part of a study examining the occurrence of chromium and natural and anthropogenic hexavalent Chromium, Cr(VI) in groundwater. Data will be used to estimate naturally-occurring background Cr(VI) concentrations upgradient, near the plume margins, and downgradient from a mapped Cr(VI) contamination plume near Hinkley, CA (Izbicki and Groover, 2016).

Date published: October 5, 2018

Bathymetry, acoustic-backscatter, and time-series datasets collected between 2014 and 2016 of a field of crescent-shaped rippled scour depressions in northern Monterey Bay, California

Between 11/14-6/16 USGS PCMSC conducted 8 repeat, high-resolution bathymetry and acoustic-backscatter surveys of a small patch of seafloor offshore Santa Cruz in northern Monterey Bay, California. We also collected oceanographic time-series data over the same two-year period. This data release provides the eight bathymetry and acoustic-backscatter datasets, the time-series data, and FGDC...

Date published: October 4, 2018

Electrical Resistivity Tomography Data at Fort Irwin National Training Center, San Bernardino County, California, 2015 and 2017

The U.S. Army Fort Irwin National Training Center (NTC), approximately 35 mi north-northeast of Barstow, California, covers approximately 1,177 square miles, and is comprised of ten groundwater basins, three of which have been subdivided into subbasins on the basis of additional hydrologic testing. Since the early 1990s, the U.S. Geological Survey (USGS) has been studying water resources...

Date published: September 24, 2018

Bathymetry and acoustic backscatter data collected in 2007 from the San Miguel Passage in the Channel Islands, California

Bathymetry and acoustic backscatter data were collected in the San Miguel Passage, Channel Islands, California in August 2007. Data collection was conducted aboard the ship R/V Shearwater as part of the USGS research cruise S-2-07-SC. The San Miguel Passage is within the Channel Islands National Marine Sanctuary, and is the body of water between the two western-most islands of the...

Filter Total Items: 450
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Year Published: 2008

Earthquake Rate Model 2 of the 2007 working group for California earthquake probabilities, magnitude-area relationships

The Working Group for California Earthquake Probabilities must transform fault lengths and their slip rates into earthquake moment-magnitudes. First, the down-dip coseismic fault dimension, W, must be inferred. We have chosen the Nazareth and Hauksson (2004) method, which uses the depth above which 99% of the background seismicity occurs to assign...

Stein, Ross S.
Earthquake Rate Model 2 of the 2007 Working Group for California Earthquake Probabilities, Magnitude-Area Relationships; 2008; OFR; 2007-1437-D; Appendix D in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); Stein, Ross S.

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Year Published: 2008

Monte Carlo method for determining earthquake recurrence parameters from short paleoseismic catalogs: Example calculations for California

Paleoearthquake observations often lack enough events at a given site to directly define a probability density function (PDF) for earthquake recurrence. Sites with fewer than 10-15 intervals do not provide enough information to reliably determine the shape of the PDF using standard maximum-likelihood techniques [e.g., Ellsworth et al., 1999]. In...

Parsons, Tom
Monte Carlo Method for Determining Earthquake Recurrence Parameters from Short Paleoseismic Catalogs: Example Calculations for California; 2008; OFR; 2007-1437-C; Appendix C in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); Parsons, Tom

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Year Published: 2008

Overview of the Southern San Andreas Fault Model

This appendix summarizes the data and methodology used to generate the source model for the southern San Andreas fault. It is organized into three sections, 1) a section by section review of the geological data in the format of past Working Groups, 2) an overview of the rupture model, and 3) a manuscript by Biasi and Weldon (in review Bulletin of...

Weldon, Ray J.; Biasi, Glenn P.; Wills, Chris J.; Dawson, Timothy E.
Overview of the Southern San Andreas Fault Model; 2008; OFR; 2007-1437-E; Appendix E in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); Weldon, Ray J., II; Biasi, Glenn P.; Wills, Chris J.; Dawson, Timothy E.

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Year Published: 2008

Summary of geologic data and development of A Priori Rupture Models for the Elsinore, San Jacinto, and Garlock faults

This appendix to the WGCEP Earthquake Rate Model 2 summarizes geologic data and documents the development of the rupture models for the Elsinore, San Jacinto, and Garlock faults. For the summary of available geologic data, the documentation is organized by fault and fault segment and includes a summary of slip rates, event timing and recurrence,...

Dawson, Timothy E.; Rockwell, Tom K.; Weldon, Ray J.; Wills, Chris J.
Summary of Geologic Data and Development of A Priori Rupture Models for the Elsinore, San Jacinto, and Garlock Faults; 2008; OFR; 2007-1437-F; Appendix F in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); Dawson, Timothy E.; Rockwell, Tom K.; Weldon, Ray J., II; Wills, Chris J.

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Year Published: 2008

WGCEP historical California earthquake catalog

This appendix provides an earthquake catalog for California and the surrounding area. Our goal is to provide a listing for all known M > 5.5 earthquakes that occurred from 1850-1932 and all known M > 4.0 earthquakes that occurred from 1932-2006 within the region of 31.0 to 43.0 degrees North and -126.0 to -114.0 degrees West. Some pre-1932...

Felzer, Karen R.; Cao, Tianqing
WGCEP Historical California Earthquake Catalog; 2008; OFR; 2007-1437-H; Appendix H in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); Felzer, Karen R.; Cao, Tianqing

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Year Published: 2008

Modified Mercalli Intensity Maps for the 1868 Hayward Earthquake Plotted in ShakeMap Format

To construct the Modified Mercalli Intensity (MMI) ShakeMap for the 1868 Hayward earthquake, we started with two sets of damage descriptions and felt reports. The first set of 100 sites was compiled by A.A. Bullock in the Lawson (1908) report on the 1906 San Francisco earthquake. The second set of 45 sites was compiled by Toppozada et al. (1981)...

Boatwright, John; Bundock, Howard
Modified Mercalli Intensity Maps for the 1868 Hayward Earthquake Plotted in ShakeMap Format; 2008; OFR; 2008-1121; Boatwright, John; Bundock, Howard

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Year Published: 2008

Forecasting California's earthquakes: What can we expect in the next 30 years?

In a new comprehensive study, scientists have determined that the chance of having one or more magnitude 6.7 or larger earthquakes in the California area over the next 30 years is greater than 99%. Such quakes can be deadly, as shown by the 1989 magnitude 6.9 Loma Prieta and the 1994 magnitude 6.7 Northridge earthquakes. The likelihood of at least...

Field, Edward H.; Milner, Kevin R.
Forecasting California's Earthquakes - What Can We Expect in the Next 30 Years?; 2008; FS; 2008-3027; Field, Edward H.; Milner, Kevin R.; The 2007 Working Group on California Earthquake Probabilities

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Year Published: 2008

The Hayward Fault - Is it due for a repeat of the powerful 1868 earthquake?

On October 21, 1868, a magnitude 6.8 earthquake struck the San Francisco Bay region. Although the region was then sparsely populated, this quake on the Hayward Fault was one of the most destructive in California?s history. Recent studies show that such powerful Hayward Fault quakes have repeatedly jolted the region in the past. U.S. Geological...

Brocher, Thomas M.; Boatwright, Jack; Lienkaemper, James J.; Prentice, Carol S.; Schwartz, David P.; Bundock, Howard
The Hayward Fault - Is It Due for a Repeat of the Powerful 1868 Earthquake?; 2008; FS; 2008-3019; Brocher, Thomas M.; Boatwright, Jack; Lienkaemper, James J.; Prentice, Carol S.; Schwartz, David P.; Bundock, Howard

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Year Published: 2008

The Uniform California Earthquake Rupture Forecast, version 2 (UCERF 2)

California?s 35 million people live among some of the most active earthquake faults in the United States. Public safety demands credible assessments of the earthquake hazard to maintain appropriate building codes for safe construction and earthquake insurance for loss protection. Seismic hazard analysis begins with an earthquake rupture forecast?a...

The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2); 2008; OFR; 2007-1437; 2007 Working Group on California Earthquake Probabilities

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Year Published: 2008

Relation between species assemblages of fishes and water quality in salt ponds and sloughs in South San Francisco Bay

This study was conducted to characterize fishery resources inhabiting salt-evaporation ponds and sloughs in South San Francisco Bay, and to identify key environmental variables that influence distribution of fishes. The ponds, which were originally constructed and operated for commercial production of salt, have undergone preliminary modifications...

Mejia, F.; Saiki, M. K.; Takekawa, John Y.
Relation between species assemblages of fishes and water quality in salt ponds and sloughs in South San Francisco Bay; 2008; Article; Journal; Southwestern Naturalist; Mejia, F.; Saiki, M. K.; Takekawa, J. Y.

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Year Published: 2007

Total selenium and selenium species in irrigation drain inflows to the Salton Sea, California, April and July 2007

This report presents the results for two sampling periods during a 4-year monitoring survey to provide a characterization of selenium concentrations in selected irrigation drains flowing into the Salton Sea, California. Total selenium, selenium species, and total suspended solids were determined in water samples, and total selenium was determined...

May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.
Total Selenium and Selenium Species in Irrigation Drain Inflows to the Salton Sea, California, April and July 2007; 2007; OFR; 2007-1347; May, Thomas W.; Walther, Michael J.; Saiki, Michael K.; Brumbaugh, William G.

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Year Published: 2007

Preliminary analytical results for ash and burned soils from the October 2007 southern California wildfires

The U.S. Geological Survey (USGS) collected ash and burned soils from about 28 sites in southern California wildfire areas (Harris, Witch, Ammo, Santiago, Canyon and Grass Valley) from Nov. 2 through 9, 2007 (table 1). USGS researchers are applying a wide variety of analytical methods to these samples, with the goal of helping identify...

Plumlee, Geoffrey S.; Martin, Deborah A.; Hoefen, Todd; Kokaly, Raymond F.; Hageman, Philip; Eckberg, Alison; Meeker, Gregory P.; Adams, Monique; Anthony, Michael; Lamothe, Paul J.
Preliminary Analytical Results for Ash and Burned Soils from the October 2007 Southern California Wildfires; 2007; OFR; 2007-1407; Plumlee, Geoffrey S.; Martin, Deborah A.; Hoefen, Todd; Kokaly, Raymond; Hageman, Philip; Eckberg, Alison; Meeker, Gregory P.; Adams, Monique; Anthony, Michael; Lamothe, Paul J.

Filter Total Items: 1,111
Gas chromatograph-mass spectrometer (GCMS) used for pesticide analysis
April 4, 2018

Gas chromatograph-mass spectrometer (GCMS) used for pesticide analysis

Organic Chemistry Research Laboratory — Sacramento, California. Gas chromatograph-mass spectrometer - GCMS

Map of California showing the sections of the coast where the USGS has generated computer models of storm impacts.
April 2, 2018

CoSMoS Implementation versions

The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-induced coastal flooding and erosion for both current and future SLR scenarios, as well as long-term shoreline change and cliff retreat.  Resulting projections for future climate scenarios (sea-level rise and storms) provide

...
View from the sky of a marsh labeled with sample locations.
April 2, 2018

Little Holland Tract and Liberty Island sample locations, 2014-2017

Sediment sampling locations in the Sacramento-San Joaquin Delta, California near Little Holland Tract and Liberty Island, 2014 to 2017

Comparison maps indicating short or long times available for earthquake shaking arrival times
March 31, 2018

Earthquake Alerts: Early and Often? Or Possibly Late?

The choice when issuing earthquake warnings is to: 1) issue alerts for weak shaking and potentially provide long warning times, but risk sending alerts for the many events that do not go on to produce damaging ground shaking, or 2) issue alerts only when ground shaking is expected to be damaging, with the tradeoff that the alert will be sent much later, reducing the

...
A coastline with trees on the beach berm on left, two people looking out at two jet skis, waves are gentle, sun is gleaming.
March 28, 2018

Nearshore survey of San Ysidro Creek

Two USGS scientists operate personal watercraft equipped with sonar and GPS along the beachfront off San Ysidro Creek, near Fernald Point in Montecito, California. They will use the data collected to create bathymetric (depth) maps. Collecting these data on a seasonal basis over many years provides a detailed picture of how the coastline reacts to changes in waves and

...
Two women stand together smiling on a boat wearing life jackets and sun hats with other safety gear.
March 27, 2018

Fieldwork in the Delta

Shruti Khanna (left, California Department of Fish and Wildlife) and Judy Drexler (USGS California Water Science Center) on the USGS Pacific Coastal and Marine Science Center’s research vessel Parke Snavely during fieldwork in the Sacramento-San Joaquin River Delta.

An object of two circular pieces of mixed materials are partially covered with mud and plant debris.
March 27, 2018

Instrument package for river data collection

Patches of dark sand cling to an instrument package that collected data for approximately two weeks at the Mokelumne River site—evidence that currents at the site were strong enough to carry sand, which is heavier than mud, probably during elevated river flows following two storms in the watershed.

A woman and a man stand on the stern of a boat wearing safety gear, man is pressing on a piece of equipment.
March 19, 2018

Gomex sediment corer preparation

Dan Powers (USGS PCMSC) and Rachel Marcuson (USGS PCMSC) prepare to deploy a Gomex sediment corer from the R/V Snavely in the Mokulumne River near confluence of San Joaquin River in the Sacramento-San Joaquin Delta, CA.

Two people hold onto a large metal tripod with instruments suspended from a cable as they guide it into the water.
March 19, 2018

Deploying tripod in the Delta

USGS physical scientist Cordell Johnson, at left, and USGS research oceanographer Jessie Lacy, both from the Pacific Coastal and Marine Science Center, guide a tripod with instruments into the waters of the Mokelumne River near the confluence with the San Joaquin River. The Mokelumne is part of the vast Sacramento-San Joaquin River Delta in California, located east of San

...
A small boat sits on calm waters with trees in the distance, and a cloudy sky.
March 14, 2018

Mokelumne River survey

Mokelumne River near confluence with the San Joaquin River in the Sacramento-San Joaquin Delta, CA, looking downstream, with Cordell Johnson (USGS PCMSC) and Rachel Allen (USGS PCMSC) collecting data from the R/V Fast Eddy.

A small boat sits on calm waters with trees in the distance, and a cloudy sky.
March 14, 2018

Mokelumne River survey

Mokelumne River near confluence with the San Joaquin River in the Sacramento-San Joaquin Delta, CA, looking downstream, with Cordell Johnson (USGS PCMSC) and Rachel Allen (USGS PCMSC) collecting data from the R/V Fast Eddy.

Filter Total Items: 980
USGS
December 11, 2014

The U.S. Geological Survey is hosting three media availabilities on Friday, Dec. 12 at high-water areas on the Russian River near Geyserville, Calif.; the Sacramento River at Delta, Calif; and Cache Creek near Yolo, Calif. A hydrologist will be available for interviews as field crews collect data.

Historical photo of a flood on Willamette River in Oregon from 1964
December 11, 2014

The Christmas flood of 1964 encompassed about 200,000 square miles, or roughly the size of France, resulted in 47 deaths, left thousands homeless and caused more than $540 million ($3.9 billion today) worth of damage.

Map showing drought coverage of California
December 8, 2014

A newly released interactive California Drought visualization website aims to provide the public with atlas-like, state-wide coverage of the drought and a timeline of its impacts on water resources.

Earthquake swarm near Lassen Volcanic Center Nov 6 to Nov 12, 2014...
November 12, 2014

CalVO is tracking an earthquake swarm that began on November 9 located at the Tehama County-Plumas County border within Lassen National Forest.

Seismicity in the Long Valley Volcanic Region between 2004 and 2014...
October 31, 2014

A cataclysmic eruption of 600 km3 of rhyolite magma (Bishop Tuff) about 760,000 years ago resulted in the collapse of the partially evacuated magma chamber to form the present 17 by 32 km (10 by 20 mi) Long Valley Caldera.

thumbnail image of flyer for Wolf and Elk Diseases in Yellowstone presentation
October 30, 2014

What can wildlife diseases tell us about the emergence of human pandemics? 

Image: Coastal Survey Vessel in Use at Santa Cruz, California
October 20, 2014

During the week of Oct 20 - 24 scientists from the U.S. Geological Survey will be working along the coastline from Santa Cruz to Moss Landing. Either by all-terrain vehicle, personal watercraft, or on foot, they will be surveying local beaches and the nearby ocean bottom to compile a three-dimensional map of how beaches change in northern Monterey Bay.

USGS
October 14, 2014

The Downtown Association of Santa Cruz will host a 25th anniversary commemoration of the Loma Prieta Earthquake.

WERC Sierra Nevadas
October 13, 2014

The USGS California Volcano Observatory (CalVO) is tracking an earthquake swarm in the Sierra Nevada range south of Long Valley Caldera, about 8 miles SW of Toms Place and 15 miles SE of the town of Mammoth Lakes.

Long Valley Caldera Earthquakes greater than M1.0 from 09/22 to 09/...
September 28, 2014

Over the past 42 hours, the earthquake swarm in California's Long Valley Caldera, which began last Friday (see September 26 post), has gradually diminished in terms of numbers of earthquakes and in earthquake magnitude.

Long Valley Caldera Earthquakes greater than M1.0 from 09/22 to 09/...
September 26, 2014

We have been closely tracking an earthquake swarm in California's Long Valley Caldera, which started yesterday at around 4AM PDT (September 25, 2014).