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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June 27, 2002

PubTalk 6/2002 — Finding Elusive Earthquake Faults

New Mapping Techniques Reveal Potential Seismic Sources Beneath Seattle

By Richard J. Blakely, Geophysicist and Ralph A. Haugerud, Geologist


  • Geophysical methods reveal "the landscape beneath the landscape"
  • Why does the Seattle Fault exist, and why is it so hard to locate and map?
  • LIDAR imagery can
March 28, 2002

PubTalk 3/2002 — Losing the Race for Survival?

The catastrophic decline of the desert tortoise in California

Kristin H. Berry, Desert Ecologist

  • Learn about the unique social behavior and fragile ecology of the desert tortoise, some of whose populations have declined by 70-90% in the past 20 years
  • Why is this fabled creature sometimes referred to as the "Methuselah
Grasslands and agricultural fields in the flat foreground, with housing development on the hills beyond.
December 31, 2000

Grasslands and agricultural fields, with housing development on the hills beyond.

Conversions of grassland/shrubland and agriculture to developed land were two common land-cover changes in Southern and Central California Chaparral and Oak Woodlands Ecoregion.

Irrigation ditch alongside an agricultural field.
December 31, 2000

Irrigation ditch alongside an agricultural field in California's Central Valley

Irrigation systems in Central California Valley Ecoregion: Single-field irrigation ditch.

Sea Otter Catpure and Tagging at Sunrise
November 30, 2000

Sea Otter Capture and Tagging at Sunrise

USGS marine biologists set sail on a crisp September morning to capture and tag wild sea otters to monitor the health of this threatened species.

Map of study area, Yucca Valley, California.
December 31, 1999

Map of study area, Yucca Valley, California.

Map of study area, Yucca Valley, California.

Two men stand by an oil well pumping unit, one man is crouched over the well, all in a forested location.
August 12, 1999

Oil well pumping unit, south area of the La Honda oil field, CA

The south area of the La Honda oil field, California, was discovered during the late 1950s and produced an estimated 595,000 barrels of oil from about 12 wells, including the well in this photo. Most of the oil was produced from an unusual fossiliferous limestone of Miocene age, informally named the Burns sand, that overlies a thick sequence of Oligocene and Miocene

Researcher in Mojave Desert
December 31, 1998

Researcher in Mojave Desert

One of 1,695 repeat photographs taken to provide context for the classification of the Central Mojave Desert into various vegetation classes.

Poster with illustrations of the underwater part of a bay, with text about the work done in the area.
December 31, 1998

Mapping Shipping Hazards in San Francisco Bay, 1997-1998

Large-scale poster describing USGS work.

The USGS mapped western San Francisco Bay using sonar, in cooperation with the National Oceanic and Atmospheric Administration (NOAA) and C&C Technologies. Some parts of the Bay floor are so shallow that a large tanker or container ship could run aground at low tide and create a massive oil spill.

The maps show how

View of the Mono Lake-Long Valley volcanic region
December 31, 1997

View of the Mono Lake-Long Valley volcanic region

An aerial view looking south of the Long Valley volcanic region in the area of Mono Lake, showing a line of rhyolite lava domes and explosion craters. An inset map shows the locations of silcic magmatic centers in the Long Valley area.

Image: Coso Volcanic Field Tumulus
October 1, 1997

Coso Volcanic Field Tumulus

A tumulus in the Coso Volcanic Field, California. This lava was probably more viscous than the lava found in the Hawaii tumuli.

Tumuli are structures usually associated with slow-moving flows. When the top of the flow crusts over, the lava beneath can well upward and create an elliptical, domed structure. Oftentimes, the pressure creates an axial fracture along the

Image: Rubens coil in the Rock Magnetics Laboratory in Menlo Park, California
December 1, 1995

Rubens coil in the Rock Magnetics Laboratory in Menlo Park, California

Rubens coil inside the Rock Magnetics Laboratory on the USGS Menlo Park campus. The function of the Rubens coil is to cancel the earth's magnetic field for thermal demagnetization of core samples. It is constructed of nonmagnetic materials and the control unit is place far enough away from the instrument to avoid interference from its metal components.

During the

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December 13, 1996

"Secrets in Stone," a video that chronicles the series of scientific discoveries in the early 1960s that led to broad acceptance of the theory of plate tectonics, will be shown for the first time on Tuesday, December 17, 1996, at the annual meeting of the American Geophysical Union (AGU) in San Francisco. The premiere showing will be held at 4:30 p.m., in Room 122 of the Moscone Center.

September 27, 1996

Dr. Crofton B. Farmer of Pasadena, California, and Dr. M. Patrick McCormick of Hampton, Virginia, have received the 1996 Pecora Award, one of the top federal awards for contributions in remote sensing.