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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old black and white photo of collapsed building, with inset image of the building before collapse
December 31, 1868

Alameda County Courthouse (Calif.) before and after 1868 Earthquake

Strong shaking during the 1868 Hayward Fault earthquake caused the second story of the Alameda County Courthouse in San Leandro to collapse (photo courtesy of the Bancroft Library, University of California). The inset photo shows the courthouse before the quake

Delta Smelt being held in hand
January 1, 0000

Delta Smelt

Delta Smelt being held in hand

Image of the front page of Sound Waves, Aug. 2011
March 22, 2019

Sound Waves, Aug. 2011

The stories in the Aug. 2011 issue of Sound Waves:


USGS Arctic Ocean Research: A Polar Ocean Acidification Study

Three-Week Expedition Images Sediments Beneath the Gulf of Alaska

A view from atop a coastal bluff looking at a sandy beach, waves, and ocean.

Sunset Beach Camera 2 Timex

Video camera timex (time-exposure) image at Sunset State Beach in Watsonville, California, looking north. Learn more about the cameras and how we're using them to study coastal change.


Whiskeytown National Recreation Area Post-fire Recovery

A landscape at Whiskeytown National Recreation Area 2 months and 9 months after summer 2018's Carr Fire near Redding, California, where USGS WERC researchers are studying fire impacts, post-fire vegetation recovery, and post-fire erosion and debris flows.

This dark image shows changes in pixels in a video image over 10 minutes.

Santa Cruz Cowells Beach video camera variance image

Video camera variance image at Cowells Beach in Santa Cruz, California, looking southward. Learn more about the cameras and how we're using them to study coastal change.

Infographic about the 2019 report "California's Exposure to Volcanic Hazards"

California's Exposure to Volcanic Hazards

Infographic about the 2019 report "California's Exposure to Volcanic Hazards"

Santa Cruz Main Beach, El Nino

Photographs are of the Santa Cruz Main Beach before and after the December 11, 2014, “Super Soaker” storm that brought 2.5 inches of rain in just a few hours to Santa Cruz and 9 inches to Boulder Creek, along with big waves and swell. While the human eye may notice changes to the beach, ground-based lidar can create surface maps of precise elevation changes over time.