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.
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Remote Sensing Coastal Change
We use remote-sensing technologies—such as aerial photography, satellite imagery, structure-from-motion (SfM) photogrammetry, and lidar (laser-based surveying)—to measure coastal change along U.S. shorelines.
2019 Regional geophysical surveys of northern and central Cascadia (offshore Washington and Oregon)
Geophysical data collected offshore of Washington and Oregon in 2019, a USGS-University of Washington partnership
2018 Regional geophysical surveys of southern Cascadia (offshore northern California and southern Oregon)
Regional geophysical surveys conducted offshore of northern California and southern Oregon in 2018, a USGS-Humboldt State University partnership
CoSMoS-Groundwater
The USGS Coastal Storm Modeling System (CoSMoS) team has extensively studied overland flooding and coastal change due to rising seas and storms. Interactions with coastal stakeholders have elucidated another important question; will rising seas also intrude into coastal aquifers and raise groundwater...
Sediment transport between estuarine habitats in San Francisco Bay
This research is part of the project “Sediment Transport in Coastal Environments”
2018 USGS-NOAA multibeam bathymetry surveys
Multibeam bathymetric surveys conducted offshore of Oregon and northern California in 2018, a USGS-NOAA partnership
SWATHplus 234kHz
The ITER Systems SWATHplus 234 kHz is an interferometric bathymetric survey tool for surveys in water depths from 1 to 200 meters.
Ecosystems: EXPRESS
The continental shelf and slope offshore California, Oregon, and Washington are home to deep-sea corals, chemosynthetic communities, and other sensitive habitats that could be impacted by the development of energy and mineral resources. The EXPRESS campaign will map and...
Evaluating the effects of wastewater-derived nutrients on phytoplankton abundance and community structure in the San Francisco Estuary and Delta
Planned upgrades to the Sacramento Regional wastewater treatment plant (SRWTP) will substantially reduce nutrient discharge and also alter the types and amounts of nutrients being distributed across the San Francisco Delta and Estuary (Delta).
One highly anticipated outcome of lower nutrients is improved productivity in the phytoplankton communities that supply aquatic food webs, which...
U.S. West Coast and Alaska Marine Geohazards
Marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis.
Devastating earthquakes in Japan (2011) and Chile (2010) that spawned pan-oceanic tsunamis sent a sobering reminder that U.S. coastlines are also vulnerable to natural disasters that originate in...
Seafloor Faults off Southern California
More than 22 million people live along Southern California’s coast, and many more migrate there every year. Faults and earthquake threats in this region have been heavily studied on land. USGS aims to boost our knowledge about faults on the seafloor, so they can be included in hazard assessments.
Underwater Landslides off Southern California
An earthquake can trigger a landslide along the ocean floor, which can then set off a tsunami. Without modern, high-resolution imaging of the seafloor, many historical slides and threats from future slides remain undetected.
Sediment transport and aquatic vegetation data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
We measured currents, suspended-sediment concentration, bed sediment characteristics, and vegetation biomass density in the Sacramento-San Joaquin Delta in 2017-2018, as part of a project investigating the influence of invasive aquatic vegetation on flow and sediment flux. This data release includes data from three sites: Lindsey Slough, Middle River, and lower Mokelumne River.
Hydrodynamic time-series data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
Hydrodynamic and sediment transport time-series data, including water depth, velocity, turbidity, conductivity, and temperature, were collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at three locations in the Sacramento-San Joaquin Delta. Data were collected in Lindsey Slough in April 2017, and Middle River and the Mokelumne River in March
Swath bathymetric data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
This part of the data release contains high-resolution swath bathymetry data collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at three locations in the Sacramento-San Joaquin Delta. Data were collected in Lindsey Slough in April 2017, Middle River in March 2018, and Mokelumne River in March 2018 using an interferometric bathymetric sidescan sonar sy
Acoustic-backscatter data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
This part of the data release contains high-resolution acoustic-backscatter data collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at three study locations in the Sacramento-San Joaquin Delta, California. Data were collected in Lindsey Slough in April 2017, Middle River in March 2018, and Mokelumne River in March 2018, using an interferometric ba
Vegetation biomass and density from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
Vegetation type and density data were collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at three locations in the Sacramento-San Joaquin Delta. Data were collected in Lindsey Slough in April 2017, and Middle River and the Mokelumne River in March 2018. Vegetation samples were collected by divers, and used to determine dry biomass density. These data
Suspended particle size distribution data from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
These data present suspended particle size distributions collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at three locations in the Sacramento-San Joaquin Delta. Data were collected in Lindsey Slough on April 4 and April 18, 2017, and near the mouth of the Mokelumne River and in Middle River on March 14, 2018 by deploying a Sequoia Scientific Lase
Grain size, bulk density, and organic carbon of sediment cores from three locations in the Sacramento-San Joaquin Delta, California, 2017 to 2018
Bed sediment samples were collected in Lindsey Slough in April 2017, and Middle River and the Mokelumne River in March 2018, to analyze for sediment properties, including bulk density, particle size distribution, and percent organic carbon. Sediment samples were collected within the vegetation with push corers deployed from a small vessel, and in the unvegetated channel with a Gomex b
Coastal Storm Modeling System (CoSMoS) for Central California, v3.1
This dataset contains spatial projections of coastal cliff retreat (and associated uncertainty) for future scenarios of sea-level rise (SLR) in Central California. Present-day cliff-edge positions used as the baseline for projections are also included. Projections were made using numerical models and field observations as part of Coastal Storm Modeling System (CoSMoS). Read metadata carefully...
Coastal Storm Modeling System (CoSMoS)
CoSMoS makes detailed predictions over large geographic scales of storm-induced coastal flooding and erosion for both current and future SLR scenarios, as well as long-term shoreline change and cliff retreat. Several versions of CoSMoS have been implemented for areas of the California coast, including Southern California, Central California, and San Francisco Bay.
CoSMoS (Coastal Storm Modeling System) Central California v3.1 water-level projections: average conditions 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 flood depth and duration projections: 100-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: 1-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
Figure 6. Map showing changes in predicted flycatcher habitat along the upper Gila River after conducting a tamarisk leaf beetle-impact simulation. The upper Gila River was divided into nine zones in order to quantify changes. A satellite model was used to predict flycatcher habitat at a 40-percent probability threshold.
Figure 5. Map showing changes in predicted flycatcher habitat along the lower Virgin River, Nevada and Arizona, 2010–2015, as determined from a satellite model at a 40-percent probability threshold.
Map showing relative changes in predicted flycatcher habitat, as determined from a satellite model at a 40-percent probability threshold, Southwestern United States, 2013–15.
Map showing area of predicted flycatcher breeding habitat (averaged across 2013–15) at all elevations in 6,521 U.S. Geological Survey 7.5-minute quadrangles, Southwestern United States. Only areas within a prescribed distance of streams and greater than stream-order 3, or within 1 kilometer of a lake or reservoir, were included in this analysis.
Figure 1. Maps showing location of the project area and the 35 U.S. Fish and Wildlife Service Southwestern Willow Flycatcher management unit boundaries, designated critical-habitat reaches, and waterbodies considered by the satellite model for regionwide modeling, Southwestern United States.
The 3DEP products and services available through The National Map consist of standard digital elevation models (DEMs) at various horizontal resolutions, elevation source and associated datasets, an elevation point query service and bulk point query service. All 3DEP products are available, free of charge and without use restrictions.
Links to publications that contain maps of the sea floor or lake beds and the digital data used to create them.
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Occurrence and sources of radium in groundwater associated with oil fields in the southern San Joaquin Valley, California
Geochemical data from 40 water wells were used to examine the occurrence and sources of radium (Ra) in groundwater associated with three oil fields in California (Fruitvale, Lost Hills, South Belridge). 226Ra+228Ra activities (range=0.010-0.51 Bq/L) exceeded the 0.185 Bq/L drinking-water standard in 18% of the wells (not drinking-water wells)....
McMahon, Peter B.; Avner Vengosh; Davis, Tracy; Landon, Matthew K.; Rebecca L. Tyne; Wright, Michael; Kulongoski, Justin T.; Hunt, Andrew G.; Peter H. Barry; A.J. Kondash; Z. Wang; Christopher J. Ballentine Preliminary report on engineering and geological effects of the July 2019 Ridgecrest earthquake sequence
The Ridgecrest Earthquake sequence included a foreshock event on July 4 2019 (M6.4) and a M7.1 mainshock event on July 5 2019. These events occurred in the Eastern California Shear Zone, near Indian Wells Valley, south of China Lake and west of Searles Valley. GEER has partnered with several organizations to collect perishable data and document...
Stewart, Jonathan P.; Brandenberg, Scott J; Wang, Pengfei; Nweke, Chukwuebuka C; Hudson, Kenneth; Mazzoni, Silvia; Bozorgnia, Yousef; Hudnut, Kenneth W.; Davis, Craig A.; Ahdi, Sean K; Zareian, Farzin; Fayaz, Jawad; Koehler, Richard D; Chupik, Colin; Pierce, Ian; Williams, Alana; Akciz, Sinan; Hudson, Martin B; Kishida, Tadahiro; Brooks, Benjamin A.; Gold, Ryan D.; Ponti, Daniel J.; Scharer, Katherine; McPhillips, Devin; Duross, Christopher; Ericksen, Todd; Hernandez, Janis; Patton, Jay; Olson, Brian; Dawson, Timothy E.; Treiman, Jerome; Blake, Kelly; Buchhuber, Jeffrey; Madugo, Chris L M; Sun, Joseph; Donnellan, Andrea; Lyzenga, Greg; Conway, Erik
Offshore shallow structure and sediment distribution, Point Sur to Point Arguello, central California
This publication consists of three map sheets that display shallow geologic structure, along with sediment distribution and thickness, for an about 225-km-long offshore section of the central California coast between Point Sur and Point Arguello. Each map sheet includes three maps, at scales of either 1:150,000 or 1:200,000, as well as a set of...
Johnson, Samuel Y.; Hartwell, Stephen R.; Watt, Janet T.; Beeson, Jeffrey W.; Dartnell, Peter Widespread initiation, reactivation, and acceleration of landslides in the northern California Coast Ranges due to extreme rainfall
Episodically to continuously active slow-moving landslides are driven by precipitation. Climate change, which is altering both the frequency and magnitude of precipitation world21 wide, is therefore predicted to have a major impact on landslides. Here we examine the behavior of hundreds of slow-moving landslides in northern California in...
Handwerger, Alexander L.; Fielding, Eric J.; Huang, Mong-Han; Bennett, Georgina L.; Liang, Cunren; Schulz, William Event detection performance of the PLUM earthquake early warning algorithm in southern California
We test the Japanese ground‐motion‐based earthquake early warning (EEW) algorithm, propagation of local undamped motion (PLUM), in southern California with application to the U.S. ShakeAlert system. In late 2018, ShakeAlert began limited public alerting in Los Angeles to areas of expected modified Mercalli intensity (IMMI) 4.0+ for magnitude 5.0...
Cochran, Elizabeth S.; Bunn, Julian; Minson, Sarah E.; Baltay, Annemarie S.; Kilb, Deborah L.; Kodera, Y.; Hoshiba, Mitsuyuki An evaluation of debris-flow runout model accuracy and complexity in Montecito, CA: Towards a framework for regional inundation-hazard forecasting
Numerous debris-flow inundation models have been applied retroactively to noteworthy events around the world. While such studies can be useful in identifying controlling factors, calibrating model parameters, and assessing future hazards in specific study areas, model parameters tailored to individual events can be difficult to apply regionally....
Bessette-Kirton, Erin; Kean, Jason W.; Coe, Jeffrey A.; Rengers, Francis K.; Staley, Dennis M. Taking the pulse of debris flows: Extracting debris-flow dynamics from good vibrations in southern California and central Colorado
The destructive nature of debris flows makes it difficult to quantify flow dynamics with direct instrumentation. For this reason, seismic sensors placed safely away from the flow path are often used to identify the timing and speed of debris flows. While seismic sensors have proven to be a valuable tool for event detection and early warning, their...
Michel, A.; Kean, Jason W.; Smith, Joel B.; Allstadt, Kate E.; Coe, Jeffrey A. Inundation, flow dynamics, and damage in the 9 January 2018 Montecito Debris-Flow Event, California, USA: Opportunities and challenges for post-wildfire risk assessment
Shortly before the beginning of the winter rainy season, one of the largest fires in California history (Thomas Fire) substantially increased the susceptibility of steep slopes in Santa Barbara and Ventura Counties to debris flows. On January 9, 2018, before the fire was fully contained, an intense burst of rain fell on the portion of the burn...
Kean, Jason W.; Staley, Dennis M.; Lancaster, Jeremy T.; Rengers, Francis K.; Swanson, Brian J.; Coe, Jeffrey A.; Hernandez, Janis; Sigman, Aaron; Allstadt, Kate E.; Lindsay, Donald N. Ground-motion residuals, path effects, and crustal properties: A pilot study in southern California
To improve models of ground motion estimation and probabilistic seismic hazard analyses, the engineering seismology field is moving toward developing fully nonergodic ground motion models, models specific for individual source‐to‐site paths. Previous work on this topic has examined systematic variations in ground‐motion along particular paths (...
Sahakian, Valerie J.; Baltay, Annemarie S.; Hanks, Thomas C.; Bueler, Janine; Vernon, Frank; Kilb, Deborah L.; Abrahamson, Norm A. A revised continuous surface elevation model for modeling
A digital elevation model (DEM) is an essential component of any hydrodynamic model. The Delta Modeling Section (Section) has maintained a database of bathymetry soundings and levee surveys for decades and published a 10-meter (10m) DEM for the San Francisco Bay and Sacramento-San Joaquin Delta (Delta) (California Department of Water Resources...
Wang, Rueen-Fang; Ateljevich, Eli; Fregoso, Theresa A.; Jaffe, Bruce E. Discovery of an extensive deep-sea fossil serpulid reef associated with a cold seep, Santa Monica Basin, California
Multi-beam mapping of the Santa Monica Basin in the eastern Pacific has revealed the existence of a number of elevated bathymetric features, or mounds, harboring cold seep communities. During 2013-2014, mounds at ~600 m water depth were observed for the first time and sampled by Monterey Bay Aquarium Research Institute’s ROV Doc Ricketts. Active...
Georgieva, Magdalena N; Paull, Charles K.; Little, Crispin TS; McGann, Mary; Sahy, Diana; Condon, Daniel; Lundsten, Lonny; Pewsey, Jack; Caress, David W; Vrijenhoek, Robert C Characterizing the catastrophic 2017 Mud Creek Landslide, California, using repeat Structure-from-Motion (SfM) photogrammetry
Along the rugged coast of Big Sur, California, the Mud Creek landslide failed catastrophically on May 20, 2017 and destroyed over 400 m of scenic California State Highway 1. We collected structure-from-motion (SfM) photogrammetry data using airborne platforms that, when combined with existing airborne lidar data, revealed that the area exhibited...
Warrick, Jonathan; Ritchie, Andrew C.; Reid, Mark E.; Schmidt, Kevin M.; Logan, Joshua B.
Grizzly Bay dolphin with weather station installed on top
A structure called a dolphin, permanently affixed in the sediment, stands in Grizzly Bay near San Francisco, CA, with a weather station installed on top. The USGS will use the data from the weather station in conjunction with other oceanographic data, in their studies of sediment movement in the bay.
Weather station power supply and modem
A weather station, installed in the middle of Grizzly Bay east of San Pablo Bay (near San Francisco), gets its power from a small solar panel. Data collected from the station is transmitted via a wireless modem. Far in the background is the city of Benicia, and the plume rising into the sky is water vapor emitted from the Benicia oil refinery.
Sampling on Grizzly Bay
On PCMSC vessel Jewell, a team of USGS scientists sit in Grizzly Bay, a baylet of San Francisco Bay in Solano County, California. USGS collects sediment samples to study how sediment moves through sensitive coastal environments like this.
Preparing for a day of sampling on Grizzly Bay
Scientists from the USGS Pacific Coastal and Marine Science Center in their vessel jewell, docked at Belden's Landing Water Access Facility on Montezuma Slough. They are preparing for a day of sampling on Grizzly Bay, where they study how sediment moves through sensitive coastal environments.
Preparing the GOMEX on Grizzly Bay
From left to right, USGS scientists Sam McGill, Lucas WinklerPrins, David Hart, Selina Davila Olivera, and Pete Dal Ferro work on Grizzly Bay on the vessel Jewell, to collect sediment samples using the GOMEX box corer.
Sediment collected in a GOMEX box corer
USGS science crew works to free the muddy sediment from a GOMEX box corer. They are on board the Pacific Coastal and Marine Science Center's vessel Jewell on Grizzly Bay in the San Francisco Bay area.
Bathymetric map of the northern portion of San Francisco Bay (MLLW)
Digital elevation model (DEM) of northern San Francisco Bay, California, created using bathymetry data collected between 1999 and 2016 (MLLW)
California coastline
The U.S. west coast is an area of complex coastal geography. This photograph depicts several examples of geological features along the California coastline that are shaped by varied coastal processes. The gently sloping beach, stark bluffs, and presence of smooth rocks suggests that the coastal processes shaping this coastline are complex.
California coastal erosion
This region of the California coastline is lined with coastal bluffs that have been shaped not only by runoff from rain, but also by wave- and wind-driven erosion. This photo from Pescadero State Beach displays an example of a bluff undergoing erosional processes. Water from the ocean, delivered in waves, can overtop some of these coastal bluffs. As water runs off the
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Natural Recharge (1981 - 2010), Indian Wells Valley, CA
The USGS California Basin Characterization Model (BCM) was used to understand the rate and amounts of natural groundwater recharge in the Indian Wells Valley and to refine historical estimates of groundwater recharge in the valley. Results from this study provide validation of recharge estimates
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Southern Cascadia topography and bathymetry
Topography and bathymetry of southern Cascadia, which includes southern Oregon and northern California (seafloor depths between 200 and 3000 m are shown in the spectrum color scale from red (shallower) to purple (deeper). The land and continental shelf are shown in grayscale slope shading where darker colors represent steeper slopes. Green lines are locations of known
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Thurston Lake and Mount Konocti, Clear Lake Volcanic Field
Thurston Lake and Mount Konocti, Clear Lake Volcanic Field, California.
Briefing held on science and policy initiatives that are helping protect West Coast ecosystems and communities from erosion, sea level rise, and other coastal hazards.
Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.
Expanding Pacific Research and Exploration of Submerged Systems (EXPRESS) Expedition Team Hosts National Oceanic and Atmospheric Administration (NOAA), USGS, and Bureau of Ocean Energy Management (BOEM) Leadership on October 21, 2019, in San Francisco
Today, the U.S. Geological Survey and the State of California pressed the “go” button to allow the first-ever statewide public testing of the California Early Earthquake Warning System, which is powered by USGS’s earthquake early warning alerts, called ShakeAlerts.
How will ShakeAlert® likely perform now on a large earthquake impacting a major urban area? How much warning will you get? To answer this, let’s do a thought experiment...
Read the new Science for Everyone article at What if the ShakeAlert Earthquake Early Warning System Had Been Operating During the M6.9 1989 Loma Prieta Earthquake?
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.
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Southwest Regional Director's Office
Phone: (916) 278-9551
Fax: (916) 278-9566
Pacific Coastal and Marine Science Center
Phone: 831-460-7401
Fax: 831-427-4748
Sacramento Projects Office (USGS California Water Science Center)
Phone: 916-278-3000
Fax: 916-278-3070
Western Ecological Research Center - Headquarters
Phone: (916) 278-9485
Fax: (916) 278-9475
Geology, Minerals, Energy and Geophysics Science Center
Phone: (650) 329-4881
Earthquake Science Center
Western Geographic Science Center - Main Office
San Diego Projects Office (USGS California Water Science Center)
Phone: 619-225-6100
Fax: 619-225-6101
Fort Collins Science Center
Phone: 970-226-9100
Fax: 970-226-9230
USGS California Volcano Observatory (CalVO package delivery)
askcalvo@usgs.gov
Phone: 650-329-5083
Poway Field Office (USGS California Water Science Center)
Phone: 858-679-4015
Fax: 858-679-4019
Truckee Field Office (USGS California Water Science Center)
Phone: 530-587-0910
Fax: 530-587-0914
Redding Field Office (USGS California Water Science Center)
Phone: 530-246-5282
Fax: 530-246-0717
Ukiah Field Office (USGS California Water Science Center)
Phone: 707-468-4040
Fax: 707-468-4022
Redlands Field Office (USGS California Water Science Center)
Phone: 909-798-3272
West Sacramento Projects Office (USGS California Water Science Center)
Phone: 916-617-2799
Eureka Satellite Office (USGS California Water Science Center)
Phone: 707-442-3169
Fax: 707-445-7860
Sacramento Field Office (USGS California Water Science Center)
Phone: 916-381-0207
Fax: 916-381-0556
Santa Cruz Field Office (USGS California Water Science Center)
Phone: 831-460-7494
Santa Maria Field Office (USGS California Water Science Center)
Phone: 805-928-9539
Fax: 805-928-9220
USGS Menlo Park Library
men_lib@usgs.gov
Phone: 650-329-5027
Fax: 650-329-5132