Unified Interior Regions


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

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Experimental laboratory setup to study uranium uptake by aquatic organisms
April 16, 2015

Experimental laboratory setup to study uranium uptake

Bio-Uptake Research Laboratory — Menlo Park, California. Experimental laboratory setup to study uranium uptake by aquatic organisms.

Earth As Art image of California's Mohave Desert
April 3, 2015


Like scratches on a marble table, airplane contrails cut across the southern California Mojave Desert. The shadows from the contrails cast dark lines across the ground. Contrails form when cold, dry air mixes with warmer aircraft exhaust. Mountains and a few dry lakebeds provide a backdrop to this scene, along with bright green spots of agriculture along the Colorado River

Plot of earthquakes in Mount Shasta region greater than M1.0 from A...
April 3, 2015

Plot of quakes in Mount Shasta region greater M1.0 from 2010 to 2016

Plot of earthquakes in Mount Shasta region greater than M1.0 from April 3, 2010 to April 3, 2015.

March 26, 2015

PubTalk 3/2015 — The Environmental Legacy of California's Gold Rush

by Andrea Foster, USGS Research Geologist & Christopher Kim, Associate Professor, Chapman University

  • Why are arsenic and mercury associated with California's gold mines?
  • What types of arsenic and mercury contamination can be directly related to historic mining?
  • How are geochemists studying the distribution and
USGS Research Geologist uses a field meter to measure magnetic susceptibility of basalt flows in the Mojave Desert.
March 12, 2015

Measuring magnetic susceptibility in the field

Research Geologist Geoff Phelps measuring basalt flow thickness and magnetic susceptibility of individual basalt flows of the Broadwell Mesa Basalt in the central Mojave Desert near Ludlow, CA. 

Research geologist using satellite imagery on tablet computers to conduct geologic mapping on a mule pack train.
March 10, 2015

Digital mapping supported by mule team

Research Geologist Kevin Schmidt and Geoff Phelps examine satellite imagery on tablet computers during geologic mapping field work near Broadwell Mesa while supported by mule pack train.  

Tubes used for collecting groundwater samples protruding from a nested groundwater well
March 8, 2015

Groundwater Sampling

A groundwater well that is outfitted with equipment to collect samples to test for several water quality parameters.

USGS hydrologists collects a groundwater sample pumped through a hose into a bottle
March 2, 2015

Groundwater Sampling in Hinkley, CA

USGS hydrologist, Carmen Burton, collects a groundwater sample from a well in Hinkley, CA. The samples are being collected as part of a study analysing the occurrance of hexavalent chromium in groundwater. 

February 26, 2015

PubTalk 2/2015 — Undamming Washington's Elwha River

by Amy East USGS Research Geologist

  • Hear about river response to the largest dam removal in history.
  • Causing disturbance as a means of restoration: how well does it work?
  • Will legendary salmon runs return?
A man stands near a tripod with an instrument on it, he is wearing field gear like hip waders, steel toed boots, field vest.
January 31, 2015

Surveying position and elevation of instruments

Josh Logan (USGS PCMSC) surveys position and elevation of instrumentation to measure water level and suspended-sediment concentration in the marsh at China Camp State Park in Marin County CA, adjacent to San Pablo Bay (northern San Francisco Bay).

Bottom of a soil pit showing the different colored soils
January 26, 2015

Marine Terrace Soil at Wilder Ranch State Park

Marine terrace soil at Wilder Ranch State Park near Santa Cruz, California. Here at the bottom of the pit, 64 inches (160cm), the colors have different mineralogy and chemistry from one another, these changes have been formed by root processes over 90,000 years of soil development.

A map shows the seafloor in a motif of dark and light areas.
December 31, 2014

Acoustic backscatter data

Acoustic backscatter data show the intensity of an acoustic pulse off the seafloor and back to a ship. Brighter tones indicate a strong intensity (possibly harder seafloor?), while darker ones indicate a weaker intensity (possibly softer seafloor?). Many seafloor physical parameters influence backscatter intensity but these data are helpful in determining the distribution

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July 18, 2007

A new study quantifies how distribution of housing developments and the kinds of fire fuels at the wildland-urban interface can help predict fires in California, a state that experiences monumental fire hazards.

June 29, 2007

Researchers from the U.S. Geological Survey (USGS) have discovered a population of the endangered desert pupfish (Cyprinodon macularius)in constructed ponds along the southeastern shore of the Salton Sea, in south-central California.

June 28, 2007

Scientists from the U.S. Geological Survey (USGS) along with colleagues from the U.S. Forest Service have published a new fact sheet which summarizes the thermal processes and associated hazards that characterize the popular Hot Creek Geologic Site near Mammoth Lakes, Calif.

May 30, 2007

The breakdown products (oxons) of the three most commonly used organophosphorus pesticides in California's agricultural Central Valley -- chlorpyrifos, malathion and diazinon -- are 10 - 100 times more toxic to amphibians than their parent compounds, which are already highly toxic to amphibians, according to experiments conducted by scientists of Southern Illinois University, Carbondale

May 16, 2007

The U.S. Geological Survey (USGS) has released a report analyzing coastal cliff retreat along more than 350 km of the California coast over a period of approximately 70 years. This study is the first comprehensive assessment of the state's historical coastal cliff retreat.

May 7, 2007

If you lived through the magnitude 6.7 Northridge earthquake in 1994 you know what a mere seven seconds of shaking can do.  Could you imagine over two minutes of intense shaking?  Scientists can.

May 4, 2007

The U.S. Geological Survey (USGS) will kick off a new program to closely align the scientific research on a variety of natural hazards to the needs of Southern California communities.

April 17, 2007

The Director of the U.S. Geological Survey (USGS) will be in San Francisco, Calif. on Thursday, April 19, to participate in a panel discussion on the need for and the importance of a national research agenda for risk reduction.

April 16, 2007

Experts Conduct Talks, Workshops and Demonstrations in San Francisco, April 17-21

April 12, 2007


San Francisco, Calif. - Today the U.S. Geological Survey (USGS) announced the launch of the new USGS Land Cover Visualization and Analysis Tool, which allows users to analyze, in specific detail, how land cover has changed over time.

April 5, 2007

New and intriguing information identified by the U.S. Geological Survey (USGS) and its partners has been published in the Journal of Geophysical Research. For the first time, researchers have identified large-scale surface uplift and expansion in the San Gabriel Valley directly caused by groundwater recharge, due to near-record rainfall in 2004-2005. 

April 3, 2007

Scientists from the U.S. Geological Survey (USGS) will review their plans to study untreated well water from several groundwater basins in five counties in the San Francisco Bay Area at a meeting Friday, April 6, in San Jose, Calif.