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
PCMSC vessel San Lorenzo
Above, the view through the windshield of San Lorenzo reveals a perfect work day on the Sacramento-San Joaquin Delta near Rio Vista, California.
PCMSC MarFac Team
Meet our team of fieldwork specialists at PCMSC's MarFac
PCMSC vessel Jewell
Above, Jewell is prepared for a day of sampling on Grizzly Bay
PCMSC Marine Facility (MarFac)
Learn about the USGS Pacific Coastal and Marine Science Center Marine Facility, or MarFac
The Blind Zone of Earthquake Early Warning
Residents in California, Oregon, and Washington have been told that earthquake early warning (EEW) is at their doorstep and will alert them to the shaking from an earthquake before it arrives. Some media reports have said there will be “up to a minute of warning”. The problem is, for onshore earthquakes these claims are exaggerated, and under some conditions a warning is not scientifically or...
Nutrient Source Identification in Groundwater and Periphyton Along the Nearshore of Lake Tahoe
High concentrations of phosphorus (P) and nitrogen (N) are responsible for excessive, or nuisance algal blooms in many ecosystems world-wide, and climate change is predicted to exacerbate the problem1,2. Excessive nutrients supplied to the nearshore zone of Lake Tahoe may have significant consequences to ecological communities, water clarity, and water quality. The nearshore zone...
Offshore Faults along Central and Northern California
From Point Conception to Cape Mendocino, seafloor faults have been, in the past, mapped in varying ways and without enough detail to assess their earthquake potential. To provide this important information, USGS uses advanced technology to image offshore faults that could trigger devastating earthquakes near densely populated areas and a nuclear power plant.
LCMAP Change Stories: Building a Boomtown, Block by Block
The desert outpost of Palm Springs, California and the surrounding Thousand Palms region has experienced explosive population growth over the past four decades, with tract after tract of development filling in previously barren landscapes along Interstate 10.
The Response of Coastal Wetlands to Sea-level Rise: Understanding how Macroscale Drivers Influence Local Processes and Feedbacks
The purpose of this work is to advance our understanding of how coastal wetland responses to sea-level rise (SLR) within the conterminous United States are likely to vary as a function of local, regional, and macroscale drivers, including climate. Based on our interactions with managers and decision makers, as well as our knowledge of the current state of the science, we propose to: (a)...
Evaluation of Groundwater Resources in the Adelaida Area of San Luis Obispo County, California
Stakeholders in San Luis Obispo County are concerned that the increased demand for water use has, and will continue to, affect groundwater levels and availability in the Adelaida area. To address stakeholder concerns, the County of San Luis Obispo Board of Supervisors has asked the USGS to conduct a comprehensive evaluation of groundwater resources of the Adelaida area.
Fourth Federal UAS Workshop
November 17 - 19, 2020 Virtual Workshop
Evaluation of groundwater resources of the Anza-Terwilliger area, Anza, California
Groundwater is the sole source for water use to the rural community and two Native American tribes in the Cahuilla Valley and Terwilliger Valley groundwater basins, which are located approximately 35 miles southwest of Palm Springs, California. The characteristics and sustainable yield of the basins are not well understood and are threatened by increasing water use and potential changes in...
CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: 1-year storm in Santa Cruz County
This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
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 sea-level rise (SLR) scen
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood-hazard projections: 100-year storm in Santa Cruz County
This data contains geographic extents of projected coastal flooding, low-lying vulnerable areas, and maximum/minimum flood potential (flood uncertainty) associated with the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-ind
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood-hazard projections: 1-year storm in Santa Cruz County
This data contains geographic extents of projected coastal flooding, low-lying vulnerable areas, and maximum/minimum flood potential (flood uncertainty) associated with the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-ind
CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: 100-year storm in Santa Cruz County
This data contains maximum model-derived ocean currents (in meters per second) for the sea-level rise (SLR) and storm condition indicated.
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 sea-level rise (SLR) scen
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood-hazard projections: average conditions in Santa Cruz County
This data contains geographic extents of projected coastal flooding, low-lying vulnerable areas, and maximum/minimum flood potential (flood uncertainty) associated with the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-ind
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood depth and duration projections: average conditions in Santa Cruz County
This data contains maximum depth of flooding (cm) in the region landward of the present-day shoreline for the sea-level rise (SLR) and storm condition indicated.
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 sea-le
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood-hazard projections: 20-year storm in Santa Cruz County
This data contains geographic extents of projected coastal flooding, low-lying vulnerable areas, and maximum/minimum flood potential (flood uncertainty) associated with the sea-level rise (SLR) and storm condition indicated.
The Coastal Storm Modeling System (CoSMoS) makes detailed predictions (meter-scale) over large geographic scales (100s of kilometers) of storm-ind
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood depth and duration projections: 20-year storm in Santa Cruz County
This data contains maximum depth of flooding (cm) in the region landward of the present-day shoreline for the sea-level rise (SLR) and storm condition indicated.
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 sea-le
CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: 20-year storm in Santa Cruz County
This data contains model-derived total water levels (in meters) for the sea-level rise (SLR) and storm condition indicated.
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 sea-level rise (SLR) scenarios. Projecti
CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: 100-year storm in Santa Cruz County
This data contains model-derived total water levels (in meters) for the sea-level rise (SLR) and storm condition indicated.
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 sea-level rise (SLR) scenarios. Projecti
CoSMoS (Coastal Storm Modeling System) Central California v3.1 wave-hazard projections: 100-year storm in Santa Cruz County
This data contains maximum model-derived significant wave height (in meters) for the sea-level rise (SLR) and storm condition indicated.
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 sea-level rise (SLR) scenar
CoSMoS (Coastal Storm Modeling System) Central California v3.1 flood depth and duration projections: 1-year storm in Santa Cruz County
This data contains maximum depth of flooding (cm) in the region landward of the present-day shoreline for the sea-level rise (SLR) and storm condition indicated.
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 sea-le
Emigration and transportation stress of juvenile Chinook salmon relative to their reintroduction upriver of Shasta Dam, California, 2017–18
The Bureau of Reclamation supports the Shasta Dam Fish Passage Evaluation (SDFPE; Yip, 2015) program, and in 2016 set out to determine the feasibility of reintroducing winter-run and spring-run Chinook salmon (Oncorhynchus tshawytscha) and steelhead (O. mykiss) to tributaries upstream of Shasta Dam. Ideally, reintroduction strategy includes...
Adams, Noah S.; Liedtke, Theresa L.; Plumb, John M.; Weiland, Lisa K.; Hansen, Amy C.; Evans, Scott D.Reported investments in earthquake mitigation top $73 to $80 billion in the San Francisco Bay Area, California, since the 1989 Loma Prieta earthquake
The purpose of this report is to provide a compilation of structural retrofits and replacements of older buildings and infrastructure in the San Francisco Bay Area that have either been completed since 1989 or that are in progress as of October 2018. For the purposes of this report, all or parts of nine Bay Area counties were included:...
Brocher, Thomas M.; Gefeke, Kerri; Boatwright, John; Knudsen, Keith L.Aeromagnetic map of Mountain Pass and vicinity, California and Nevada
Magnetic investigations of Mountain Pass and vicinity were begun as part of an effort to study regional crustal structures as an aid to understanding the geologic framework and mineral resources of the eastern Mojave Desert. The study area, which straddles the state boundary between southeastern California and southern Nevada, encompasses Mountain...
Ponce, David A.; Ponce, David A.; Denton, Kevin M.Isostatic gravity map of Mountain Pass and vicinity, California and Nevada
Gravity investigations of Mountain Pass and vicinity were begun as part of an effort to study regional crustal structures as an aid to understanding the geologic framework and mineral resources of the eastern Mojave Desert. The study area, which straddles the state boundary between southeastern California and southern Nevada, encompasses Mountain...
Ponce, David A.; Ponce, David A.; Denton, Kevin M.Geophysical and geologic maps of Mountain Pass and vicinity, California and Nevada
U.S. Geological Survey Scientific Investigations Map 3412 is a series of products that consists of geophysical and geologic maps of Mountain Pass and vicinity, California. Maps A and B (red outline in above map image) are gravity and aeromagnetic maps, respectively. The map series was begun as part of an effort to study regional crustal structures...
Ponce, David A.Improving earthquake rupture forecasts using California as a guide
This article discusses ways in which earthquake rupture forecast models might be improved. Because changes are most easily described in the context of specific models, the third Uniform California Earthquake Rupture Forecast (UCERF3) and its presumed successor, UCERF4, is used as a basis for discussion. Virtually all of the issues and possible...
Field, Edward H.2018 hurricane and wildfire supplemental funding: USGS recovery activities
The Additional Supplemental Appropriations for Disaster Relief Requirements Act, 2018 (P.L. 115-123), was signed by the President on February 9, 2018. This funding provided $42.2 million to the U.S. Geological Survey (USGS) for equipment repair and replacement, high-resolution elevation data collection in both hurricane- and wildfire-impacted...
Hinck, Jo Ellen; Stachyra, JosephIncreasing earthquake insurance coverage in California via parametric hedges
California has the highest earthquake risk of any state in the United States. The Federal Emergency Management Agency (FEMA) reported in 2017 that 73% of the nation’s annual losses to earthquakes were expected to be concentrated in California and the Pacific Northwest. California alone constitutes 61% ($3.7 billion out of an estimated $6.1 billion...
Franco, Guillermo; Tirabassi, G; Lopeman, M; Wald, David J.; Siembieda, W.J.State transportation agencies partner to deploy and enhance ShakeCast
The California Department of Transportation (Caltrans) is organizing and leading a three-year Transportation Pooled Fund (TPF) project, Connecting the Dots: Implementing ShakeCast Across Multiple State Departments of Transportation for Rapid Post-Earthquake Response. Ten state Departments of Transportation (DOT)—CA, ID, MO, MS, OK, OR, SC, TX, UT...
Turner, L.; Wald, David J.; Lin, Kuo-wan; Chiou, Brian; Slosky, DanielIdentifying physics‐based thresholds for rainfall‐induced landsliding
Most regional landslide warning systems utilize empirically derived rainfall thresholds that are difficult to improve without recalibration to additional landslide events. To address this limitation, we explored the use of synthetic rainfall to generate thousands of possible storm patterns and coupled them with a physics‐based hydrology and slope...
Thomas, Matthew A.; Mirus, Benjamin B.; Collins, Brian D.A physics-based earthquake simulator replicates seismic hazard statistics across California
Seismic hazard models are important for society, feeding into building codes and hazard mitigation efforts. These models, however, rest on many uncertain assumptions and are difficult to test observationally because of the long recurrence times of large earthquakes. Physics-based earthquake simulators offer a potentially helpful tool, but they...
Shaw, Bruce E.; Milner, Kevin R.; Field, Edward H.; Richards-Dinger, Keith B.; Gilchrist, Jacquelyn J.; Dieterich, James H.; Jordan, Thomas H.Flow-mediated effects on travel time, routing, and survival of juvenile Chinook salmon in a spatially complex, tidally forced river delta
We evaluated the interacting influences of river flows and tides on travel time, routing, and survival of juvenile late-fall Chinook salmon (Oncorhynchus tshawytscha) migrating through the Sacramento–San Joaquin River Delta. To quantify these effects, we jointly modeled the travel time, survival, and migration routing in relation to individual...
Perry, Russell W.; Pope, Adam C.; Romine, Jason G.; Brandes, Patricia L.; Burau, Jon R.; Blake, Aaron R.; Ammann, Arnold J.; Michel, Cyril J.Building 1 and Credit Union on USGS Menlo Park campus
Building 1 formerly housed many different USGS groups, including the Western Coastal and Marine Geology team, but slowly has been leased out to other federal agencies like the Transportation Security Administration (TSA) and Veterans Affairs (VA). At the right is the Menlo Survey Federal Credit Union.
Thurston Lake and Mount Konocti, Clear Lake Volcanic Field
Thurston Lake and Mount Konocti, Clear Lake Volcanic Field, California.
Image of the Week - Fires Across California
Fires burned across California in late 2019. Fall is the state's most dangerous season for wildfires, propelled by dry and windy conditions. In recent years however, the fall fire season has been starting earlier and ending later. A series of images from the MODIS sensor on NASA's Terra and Aqua satellites show the Kincade Fire in northern California. This fire started on
Scientist adjusts equipment mounted on tower at the Suisun Marsh
USGS Research Scientist Ellen Goodrich-Stuart adjusts a CH4 (Methane) analyzer mounted on the eddy covariance flux tower at the Rush Ranch site at Suisun Marsh.
PubTalk 11/2019 —Sea-Level Rise, Extreme Water Levels, Coastal Erosion
Title: Sea-Level Rise, Extreme Water Levels, and Coastal Erosion ... How bad could it possibly be?
- Sea-level rise represents an unprecedented civil engineering challenge.
- Small amounts of sea-level rise can disproportionately increase the frequency of coastal flooding.
- One-third to two-thirds of the beaches in Southern California may disappear
Wintering Waterfowl at Sacramento National Wildlife Refuge
In this video, you can hear the honks and quacks of geese and ducks ring through the air, as birds fly in every direction above a wetland. This video was captured at Sacramento National Wildlife Refuge in November 2019, not long after geese and ducks began to arrive to spend the winter in the California Central Valley.
2019 November Public Lecture
2019 November Public Lecture Flyer
Sea-Level Rise, Extreme Water Levels, and Coastal Erosion ... How bad could it possibly be?
By Sean Vitousek, USGS Research Oceanographer
- Sea-level rise represents an unprecedented civil engineering challenge.
- Small amounts of sea-level rise can disproportionately increase the frequency
Hooray for sediment cores!
Dr. Nora Nieminski is a research geologist and Mendenhall Fellow at the USGS Pacific Coastal and Marine Science Center in Santa Cruz, California. She is pictured here, on board Marine Vessel Bold Horizon, with a piston core sample collected from the southern Cascadia subduction zone offshore of northern California/southern Oregon. The
...Chirp rests on the deck of R/V Bold Horizon
This instrument, the Edgetech SB-516 or "chirp", emits acoustic signals that penetrate the sediment on the seafloor. The reflected sound is recorded and is used to create a cross-section image, or profile, of the sub-bottom.
Klamath River mouth
A view of the mouth of the Klamath River where it meets the Pacific Ocean in northern California. The river runs from Oregon to California. Four dams along the Klamath are pending removal. USGS is studying coastal watershed response to dam removal, including long-term before-after/control-impact (BACI) studies.
Initial Observations of Cypress Structure Collapse, Oakland, CA 1989
Retrospective interview with USGS Geophysicist Susan Hough about the collapse of the Nimitz Freeway (known as the Cypress Structure) in Oakland, CA, during the October 17, 1989 Loma Prieta Earthquake and how the first responders reacted to the event.
Sight Response and Cypress Structure Collapse, Oakland, CA 1989
Retrospective interview with USGS Geophysicist Susan Hough about her early earthquake work during the 1989 Loma Prieta earthquake. The interview covers how the Cypress Structure collapse in Oakland, CA, served as a site response study for seismic research.
Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.
Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.
Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.
Keep up to speed with our EXPRESS research cruise with this latest seafloor syntax!

Effects from the two July 2019 Ridgecrest, CA earthquakes were observed in several USGS continuous groundwater-level monitoring sites in California, Nevada, and Arizona.

Two new publications underscore the role of wind in destructive California wildfires
Next week, USGS and the nation commemorate the 30th anniversary of one of the most destructive earthquake disasters in U.S. history – the 1989 Loma Prieta earthquake in northern California. The magnitude 6.9 quake struck on October 17 in the southern portion of the San Francisco Bay Area near Santa Cruz and was responsible for the deaths of 63 people and more than 3,500 injuries.

Two of the first questions that come to mind for anyone who just felt an earthquake are, “Will there be another one?” and “Will it be larger?”.
Read Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?

Do you get excited about working outdoors? Do you enjoy creative problem solving? Would you like to work part to full time in a challenging position that could lead to incredible career opportunities?
USGS researcher quoted in major news stories about the August 2 coastal cliff collapse that killed three people on a beach in Encinitas, California

GSA's news release on the recent USGS-authored publication from the Landslide Hazards Program: Inundation, flow dynamics, and damage in the 9 January 2018 Montecito debris-flow event, California, USA: Opportunities and challenges for post-wildfire risk assessment.
Dr. Nate Stephenson says the rules are changing for Sierra Nevada trees