Unified Interior Regions

California

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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.

News

Date published: December 5, 2019

Airplane to Make Low-Level Flights Over Parts of the Eastern Mojave Desert, California and Nevada

For about two months, starting around December 7, 2019, an airplane operated under contract to the USGS will be making low-level flights over parts of the eastern Mojave Desert.

Date published: December 5, 2019

Resilience along the West Coast

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.

Date published: October 30, 2019

WaterWords-Aragonite

Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.

Filter Total Items: 363
A moving illustration shows how waves develop, grow, and move in and around a bay near the ocean following an earthquake.
Date Published: December 11, 2019
Status: Completed

Tsunami Record from the Great 1906 San Francisco Earthquake

Shortly after the Great San Francisco earthquake of April 18, 1906, a sea level disturbance (tsunami) was recorded at the Presidio tide gauge station in San Francisco (the station is now located nearby at Ft. Point). What type of mechanism (earthquake rupture, landslide, other) generated the tsunami...

Contacts: Eric Geist
An ad for an upcoming seminar with the title at top, image in middle, and speaker name and information at bottom.
Date Published: November 25, 2019
Status: Active

Science Seminar Series

Upcoming public seminars at the Pacific Coastal and Marine Science Center in Santa Cruz, California will be listed here. Get directions to our Center.
Also, check out our archive of past seminars.

Scientist adjusts equipment mounted on tower at the Suisun Marsh in California.
Date Published: November 22, 2019
Status: Active

Creating a Model to Predict Future Carbon Levels in Tidally-driven Marshes

Tidal marshes are important ecosystems in the San Francisco-Bay Delta. They remove carbon from the atmosphere, they build up soils that buffer our communities from sea level rise, they provide critical habitat and food resources for a diversity of species, and they reduce excessive nutrients which have a negative impact on water quality. As a result of land-use change and urbanization, the San...

Map with streets, parks, and other features labeled.
Date Published: November 14, 2019
Status: Active

Attending Seminars at PCMSC

Check our schedule for upcoming seminars and dates.

USGS
Date Published: November 13, 2019
Status: Active

Earthquake Early Warning Seismic Station Adjustment Terms - Annemarie Baltay

Earthquake early warning, live in California, aims to send user alerts before ground shaking arrives at their location. Work directly with a USGS team in implementing a ground-motion based early warning algorithm, and develop novel station-specific adjustment factors to improve the accuracy of ground-shaking estimates, a critical step in sending the most useful user alerts.

grassy slope with landslide monitoring instrument
Date Published: October 23, 2019
Status: Active

San Francisco Bay Area – SF Peninsula (BALT4) Site near Pacifica, CA

Recent Conditions

The instruments for this site were installed in the winter of 2012 and are used to monitor and detect changes in local conditions.  Soil water content and ground water pressure are monitored at two nests on the same hillslope.  Data for the site include:

  • ...
Contacts: Brian Collins
dry grassy slope with landslide monitoring instrument
Date Published: October 23, 2019
Status: Active

San Francisco Bay Area – SF Peninsula (BALT3) Site near Brisbane, CA

Recent Conditions

The instruments for this site were installed in the summer of 2011 and are used to monitor and detect changes in local conditions.  Soil water content and ground water pressure are monitored at two nests on the same hillslope.  Data for the site include:

  • ...
Contacts: Brian Collins
steep dry grassy slopes in foreground with populated valley in background
Date Published: October 23, 2019
Status: Active

San Francisco Bay Area – Marin County (BALT2) Site near San Rafael, CA

Recent Conditions

The instruments for this site were installed in the winter of 2010 and are used to monitor and detect changes in local conditions.  Soil water content and ground water pressure are monitored at two nests on the same hillslope.  Data for the site include:

  • ...
Contacts: Brian Collins
Sediment cores collected in Guatemala
Date Published: October 23, 2019
Status: Active

Drivers and Impacts of North Pacific Climate Variability

Climate model forecasts indicate an increase in extreme hydrologic events, including floods and droughts, for California and the western U.S. in the future. To better understand what the consequences of this future change in climate may be, USGS scientists are studying the frequency, magnitude, and impacts of past hydroclimate variability and extremes in the region. This project produces well-...

vertical timeline with text bullets
Date Published: October 17, 2019
Status: Completed

What if the ShakeAlert Earthquake Early Warning System Had Been Operating During the M6.9 1989 Loma Prieta Earthquake?

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...

A bottomfish with small, bright spots lazily swims over a rocky seafloor among a few small pieces of kelp.
Date Published: October 17, 2019
Status: Active

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...

Block Island Wind Farm
Date Published: October 17, 2019
Status: Active

Resources: EXPRESS

Along the U.S. west coast, the Pacific Ocean, ocean floor, and winds above contain potentially vast energy and mineral resources. Developing these resources safely and wisely requires detailed information for each area of interest. One goal of EXPRESS is to inform ocean...

Filter Total Items: 323
USGS
November 27, 2019

High-resolution Chirp seismic-reflection data were collected by the U.S. Geological Survey in September 2006 offshore San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Chirp data were collected using an EdgeTech 512 chirp subbottom profiler and recorded with a Triton SB-Logger.

USGS
November 27, 2019

High-resolution single-channel Chirp and minisparker seismic-reflection data were collected by the U.S. Geological Survey in September and October 2006, offshore Bolinas to San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Chirp data were collected using an EdgeTech 512 chirp subbottom system and were recorded with a Triton SB-Logger. Minispark

USGS
November 27, 2019

High-resolution single-channel minisparker seismic-reflection data were collected by the U.S. Geological Survey in March and April 2007 from San Francisco to San Gregorio, offshore San Mateo County, California. Data were collected aboard the R/V Fulmar, during field activity F-02-07-NC. Minisparker data were collected using a SIG 2-mille minisparker sound source combined with a single-channel str

USGS
November 27, 2019

High-resolution single-channel Chirp seismic-reflection data were collected by the U.S. Geological Survey in March and April 2007 from Pacifica to Half Moon Bay, offshore San Mateo County, California. Data were collected aboard the R/V Fulmar, during field activity F-02-07-NC. Chirp data were collected using an EdgeTech 512 chirp subbottom system and recorded with a Triton SB-Logger.

USGS
November 27, 2019

High-resolution single-channel Chirp and minisparker seismic-reflection data were collected by the U.S. Geological Survey in March and April 2007, offshore San Mateo County, California. Data were collected aboard the R/V Fulmar during field activity F-02-07-NC. Chirp data were collected using an EdgeTech 512 chirp subbottom system and were recorded with a Triton SB-Logger. Minisparker data were c

USGS
November 27, 2019

High-resolution single-channel minisparker seismic-reflection data were collected by the U.S. Geological Survey in September and October 2006 offshore Bolinas to San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Minisparker data were collected using a SIG 2-mille minisparker sound source combined with a single-channel streamer, and recorded wit

Map of a western coastline with stretches of the coast labeled to identify data set regions.
October 17, 2019

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.

USGS
October 4, 2019

This data release documents 155 sets of dissolved noble gas analyses (neon, argon, krypton, xenon) and 153 modeled recharge temperatures for groundwater sampled from domestic water supply wells and springs throughout the northern Sierra Nevada foothills as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program in 2015-2017.

USGS
October 1, 2019

Beginning in November of 2015, a project was undertaken to reanalyze approximately 60,000 archived sample splits collected as part of the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) project from selected areas in Arizona, California, Idaho, Montana, Nevada, New Mexico, and Utah. A small amount (approximately 0.25 g) of sieved -75 micron s

USGS
September 26, 2019

Groundwater age distribution and susceptibility to natural and anthropogenic contaminants were assessed for selected principal aquifers of the Western United States: the Central Valley aquifer system (CVAL), the Basin and Range basin-fill aquifers (BNRF), the Rio Grande aquifer system (RIOG), the High Plains aquifer (HPAQ), the Columbia Plateau basaltic-rock aquifers (CLPT), and the Colorado Plat

map of Indian Wells Valley displaying subbasin boundaries and shaded by recharge in mm/year
September 12, 2019

This data Set includes: 1) A shapefile of the Indian Wells Valley sub watersheds containing 9 sub-watersheds, 2) Geology shapefile of all the watersheds 3) Vegetation shapefile of all the watersheds 4) Basin Characterization Model (BCM) model output of recharge values for all the watersheds from 3 model runs (CanESM2, CCSM4, and HadGEM2-CC)

Long thin colorful shape, a map of a strip of coastline whose colors correspond to varying offshore sediment thicknesses.
July 22, 2019

Each GIS data file is listed with a brief description, a small image, and links to the metadata files and the downloadable data files. The data were compiled in ArcMap. Raster data layers are registered TIFF images and are in the UTM Zone 10 coordinate system. Line features are in shapefile format and are projected in UTM Zone 10 coordinates.

Filter Total Items: 24
map of California shaded by GAMA deep aquifer study units
June 18, 2019

The GAMA program is a comprehensive statewide assessment designed to help better understand and identify risks to groundwater resources. Groundwater is sampled at many locations across California in order to characterize its constituents and identify trends in groundwater quality. The results of these tests provide information for water agencies to address a variety of water resource issues.

map of California shaded by GAMA shallow aquifer study units
June 18, 2019

n 2012, the Groundwater Ambient Monitoring & Assessment Priority Basin Project (GAMA-PBP) began water-quality assessments of shallow aquifers, which are typically used for private domestic and small system drinking-water supplies. GAMA-PBP is designed to identify where and to what extent water quality of groundwater aquifers meets benchmarks that have been established for drinking water.

maps of the 5 coastal drainage basins in San Diego County
May 16, 2019

Coastal Basins of San Diego County, California, and Northern Baja California, Mexico.  Local features include the San Dieguito River Basin, San Diego River Basin, Sweetwater River Basin, and Otay River Basin.  Maps also display locations of groundwater-monitoring sites. 

Screenshot of the Borrego Valley groundwater quality data map
January 30, 2019

The quality of groundwater in the Borrego Valley is a concern because it is the sole source of water for agricultural, recreational, and public supply. Explore this interactive water-quality data map for detailed information and to download data.

screenshot of interactive data map displaying  USGS wells in the San Antonio Creek groundwater basin
December 18, 2018

In order to understand the integrated hydrologic systems in the San Antonio Creek Valley, many different types of data are being gathered from both the surface water and groundwater system. Learn about these data types and explore them with the interactive map.

screenshot of interactive map displaying groundwater, water quality, streamgage, and microgravity sites
December 10, 2018

The Lower Colorado Monitoring Network is a series of groundwater-level and water-quality wells, as well as streamgages and micro-gravity sites. This interactive map displays the sites and provides links to the most current data.

Map of California with areas of subsidence shaded by cause
December 7, 2018

In California, land subsidence—mostly from groundwater pumping—was first documented by the USGS in the early 20th century. Completion of State and Federal water projects that bring water from California's wet north to its dry south allowed some groundwater aquifers to recover, and subsidence decreased in these areas. Subsidence continues today, sometimes at high rates of more than 1 foot/year.

screenshot of the user interface
November 13, 2018

This interactive webmap plots water-quality data from domestic and public-supply wells sampled by the USGS for the California Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin Project (GAMA-PBP), and allows users to download datasets. The GAMA-PBP is a cooperative program between the California State Water Resources Control Board and the U.S. Geological Survey. 

screenshot of an interactive map of groundwater data in the Mojave region.  Well sites and water-level contours are displayed.
November 7, 2018

Interactive map of the Mojave and Morongo groundwater basins.  Data layers include sites and data for groundwater levels, water quality, and land subsidence.  Groundwater data spans 1994 to the present.

Map displaying areas in California where the USGS has built groundwater models
August 30, 2018

The USGS models shown on this site are in the public domain, and are freely available. They are based on MODFLOW and other public-domain USGS software. Links to publications and web resources associated with each model are shown in the table next to the model map. The associated model files for some of these models are currently available via download.

Thumbnail image of the cover of USGS Fact Sheet 2016-3020
April 16, 2018

Using information from recent earthquakes, improved mapping of active faults, and a new model for estimating earthquake probabilities, the 2014 Working Group on California Earthquake Probabilities updated the 30-year earthquake forecast for California. They concluded that there is a 72 percent probability (or likelihood) of at least one earthquake of magnitude 6.7 or greater striking somewhere in

Filter Total Items: 314
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Year Published: 2019

Simple metrics predict salt-marsh sediment fluxes

The growth (or decay) of salt marshes depends on suspended-sediment flux into and out of the marsh. Suspended-sediment concentration (SSC) is a key element of the flux, and SSC-based metrics reflect the long-term sediment-flux trajectories of a variety of salt marshes. One metric, the flood–ebb SSC differential, correlates with area-normalized...

Nowacki, Daniel J. ; Ganju, Neil Kamal

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Year Published: 2019

A multidisciplinary coastal vulnerability assessment for local government focused on ecosystems, Santa Barbara area, California

Incorporating coastal ecosystems in climate adaptation planning is needed to maintain the well-being of both natural and human systems. Our vulnerability study uses a multidisciplinary approach to evaluate climate change vulnerability of an urbanized coastal community that could serve as a model approach for communities worldwide, particularly in...

Myers, Monique; Barnard, Patrick L.; Beighley, Edward; Cayan, Daniel R.; Dugan, Jenifer E.; Feng, Dongmei; Iacobellis, Samuel F.; Melack, John M.; Page, Henry M.

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Year Published: 2019

Sediment and organic carbon transport and deposition driven by internal tides along Monterey Canyon, offshore California

Submarine canyons provide globally important conduits for sediment and organic carbon transport into the deep-sea. Using a novel dataset from Monterey Canyon, offshore central California, that includes an extensive array of water column sampling devices, we address how fine-grained sediment and organic carbon are transported, mixed, fractionated,...

Maier, Katherine L.; Rosenberger, Kurt J.; Paull, Charles K.; Gwiazda, Roberto; Gales, Jenny; Lorenson, Thomas; Barry, James P.; Talling, Peter J.; McGann, Mary; Xu, Jingping; Lundsten, Eve M.; Anderson, Krystle; Litvin, Steven; Parsons, Daniel; Clare, Michael; Simmons, Stephen; Sumner, Esther J; Cartigny, Matthieu J.B.

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Year Published: 2019

κ0 and broadband site spectra in Southern California from source model-constrained inversion

Ground-motion modeling requires accurate representation of the earthquake source, path, and site. Site amplification is often modeled by VS30, the time-averaged shear-wave velocity of the top 30 meters of the Earth’s surface, though recent studies find that its ability to accurately predict site effects varies. Another measure of the site is κ0,...

Klimasewski, Alexis; Sahakian, Valerie J.; Baltay, Annemarie S.; Boatwright, John; Fletcher, Jon Peter; Baker, Lawrence

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Year Published: 2019

Santa Rosa's past and future earthquakes

Santa Rosa is no stranger to earthquakes. This northern California city was damaged several times in the late 19th and early 20th centuries by shaking from earthquakes, culminating in the devastating earthquake of 1906, whose rupture passed 20 miles to the west of the city on the San Andreas Fault. Then in 1969, Santa Rosa was again strongly...

Hecker, Suzanne; McPhee, Darcy K.; Langenheim, Victoria E.; Watt, Janet T.
Hecker, S., McPhee, D.K., Langenheim, V.E., and Watt, J.T., 2019, Santa Rosa's past and future earthquakes: U.S. Geological Survey Fact Sheet 2019–3035, 4 p., https://doi.org/10.3133/fs20193035.

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Year Published: 2019

Offshore shallow structure and sediment distribution, Punta Gorda to Point Arena, Northern California

This publication consists of two map sheets that display shallow geologic structure, along with sediment distribution and thickness, for an approximately 150-km-long offshore section of the northern California coast between Punta Gorda and Point Arena. Each map sheet includes three maps at scales of either 1:100,000 or 1:200,000, and together the...

Beeson, Jeffrey W.; Johnson, Samuel Y.
Beeson, J.W., and Johnson, S.Y., 2019, Offshore shallow structure and sediment distribution, Punta Gorda to Point Arena, northern California: U.S. Geological Survey Open-File Report 2019–1072, 2 sheets, scales 1:100,000 and 1:200,000, https://doi.org/10.3133/ofr20191072.

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Year Published: 2019

Airborne radiometric maps of Mountain Pass, California

Geophysical 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 encompasses Mountain Pass, host to one of the world’s largest rare earth element carbonatite deposits. The...

Ponce, David A.; Ponce, David A.; Denton, Kevin M.
Ponce, D.A., and Denton, K.M. (D.A. Ponce, ed.), 2019, Airborne radiometric maps of Mountain Pass, California: U.S. Geological Survey Scientific Investigations Map 3412–C, scale 1:62,500, https://doi.org/10.3133/sim3412C.

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Year Published: 2019

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
McMahon, P.B., A. Vengosh, T.A. Davis, M.K. Landon, R.L. Tyne, M.T. Wright, J.T. Kulongoski, A.G. Hunt, P.H. Barry, A.J. Kondash, Z. Wang, C.J. Ballentine, 2019. Occurrence and sources of radium in groundwater associated with oil fields in the southern San Joaquin Valley, California. Environmental Science & Technology, 53, 9398-9406.

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Year Published: 2019

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
Stewart, J.P. (ed.), Brandenberg, S.J., Wang, Pengfei, N., Chukwuebuka C., Hudson, K., Mazzoni, S., Bozorgnia, Y., Hudnut, K.W., Davis, C.A., Ahdi, S.K., Zareian, F., Fayaz, J., Koehler, R.D., Chupik, C., Pierce, I., Williams, A., Akciz, S., Hudson, M.B., Kishida, T., Brooks, B.A., Gold, R.D., Ponti, D.J., Scharer, K.M., McPhillips, D.F., Ericksen, T.., Hernandez, J., Patton, J., Olson, B., Dawson, T., Treiman, J., Duross, C.B., Blake, K., Buchhuber, J., Madugo, C., Sun, J., Donnellan, A., Lyzenga, G., and Conway, E., 2019, Preliminary report on engineering and geological effects of the July 2019 Ridgecrest Earthquake sequence: Geotechnical Extreme Event Reconnaissance Association Report GEER-064, https://doi.org/10.18118/G6H66K.

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Year Published: 2019

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
Johnson, S.Y., Hartwell, S.R., Watt, J.T., Beeson, J.W., and Dartnell, P., 2019, Offshore shallow structure and sediment distribution, Point Sur to Point Arguello, central California: U.S. Geological Survey Open-File Report 2018–1158, 3 sheets, scales 1:150,000 and 1:200,000, https://doi.org/10.3133/ofr20181158.

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Year Published: 2019

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

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Year Published: 2019

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

Filter Total Items: 6
multicolored map of Ocean Shores, Washington
April 13, 2017

The Pedestrian Evacuation Analyst is an ArcGIS extension that estimates how long it would take for someone to travel on foot out of a hazardous area that was threatened by a sudden event such as a tsunami, flash flood, or volcanic lahar. It takes into account the elevation changes and the different types of landcover that a person would encounter along the way.

schematic one water hydrologic model
November 5, 2014

The One-Water Hydrologic Flow Model (MF-OWHM) (Hanson and others, 2014) is a MODFLOW-based integrated hydrologic flow model (IHM) that is the most complete version, to date, of the MODFLOW family of hydrologic simulators needed for the analysis of a broad range of conjunctive-use issues. 

MODPATH-OBS_distance-direction-observations_USGS-hydrologic-modelling
April 26, 2013

The MODPATH-OBS (Hanson and others, 2013) computer program is designed to calculate simulated equivalents for observations related to advective groundwater transport that can be represented in a quantitative way by using simulated particle-tracking data. 

map of the central valley with the CVHM grid cells overlaid, and a cross section of the subsurface
August 27, 2012

The Central Valley Hydrologic Model (CVHM) is an extensive, detailed three-dimensional (3D) computer model of the hydrologic system of the Central Valley (Faunt, 2009). The Central Valley Hydrologic Model (CVHM) simultaneously accounts for changing water supply and demand across the landscape, and simulates surface water and groundwater flow across the entire Central Valley.

subsurface grid showing relationship surface water and groundwater recharge
June 19, 2008

A Grid-Based, Distributed-Parameter Watershed Model to Estimate Net Infiltration Below the Root Zone

Filter Total Items: 1,145
Number of earthquakes from the past 30 days - Long Valley Caldera
December 31, 2019

Number of earthquakes from the past 30 days - Long Valley Caldera

 

The graph shows the number of earthquakes from the past 30 days for Long Valley Caldera.

Earthquakes at Long Valley Caldera 1984 to present
December 31, 2019

Earthquakes at Long Valley Caldera 1984 to present

The vertical bars on the graphs below correspond with the left-side y-axis and represent the number of earthquakes per day. The red line indicates the cumulative number of earthquakes and corresponds with the right-side y-axis. Earthquake swarms occurred at Long Valley from 1978-1983, 1990-1995, 1996, and 1997-1998. The rate of earthquakes since the end of the last swarm 

...
map of Indian Wells Valley displaying subbasin boundaries and shaded by recharge in mm/year
December 31, 2019

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

...
December 11, 2019

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 in California.
November 22, 2019

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. 

Flyer with images of sea-level rise with ocean waves
November 6, 2019

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
...
October 17, 2019

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.
 

October 17, 2019

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.
 

October 17, 2019

The Great California ShakeOut (2019) Role Play Exercise - Biola Univ.

Each year the State of California promotes a ShakeOut event where local citizens practice earthquake response and preparedness. This video shows footage from the 2019 Great California ShakeOut, which was hosted at Biola University in La Mirenda, CA. Video includes footage of the initial ShakeAlert announcement that blared across campus. Additional footage includes first

...
map of 6 wells & hydrographs showing groundwater-level responses to the July 2019 Ridgecrest earthquakes
October 15, 2019

Groundwater-level Response to the July 2019 Ridgecrest, CA Earthquakes

Locations of the July 2019 earthquake epicenters and six USGS groundwater-monitoring sites. The hydrographs show the response of groundwater levels to the earthquakes.  Sites shown are California (1) 

...
October 10, 2019

October 17, 1989 (Part 1)

On October 17, 1989, at 5:04 pm a magnitude M6.9 earthquake struck near Loma Prieta, California. It was a tragic reminder of the destructive power of earthquakes. However, it was also a watershed moment in seismic research. 30 years later, we revisit the earthquake through the eyes of the scientists who experienced it. And studied it. These are their stories. In Part 1 (of

...
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Satellite imagery of the December 2019 low flying survey looking at geology, hydrology and natural resources of the region
December 5, 2019

For about two months, starting around December 7, 2019, an airplane operated under contract to the USGS will be making low-level flights over parts of the eastern Mojave Desert.

Dr. Barnard
December 5, 2019

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.

USGS scientist Nancy Prouty collects deep-sea water samples as part of the EXPRESS 2019 expedition
October 30, 2019

Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.

gray-scale map of San Francisco Bay area
October 17, 2019

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.

vertical timeline with text bullets
October 17, 2019

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?

Deep-sea organisms
October 16, 2019

Keep up to speed with the latest USGS deep-sea research cruise with this seafloor syntax.

ROV control room
October 16, 2019

Keep up to speed with our EXPRESS research cruise with this latest seafloor syntax!

aerial view of road damage after the Ridgecrest, CA earthquake
October 15, 2019

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

Ground view of collapsed building and burned area, Beach and Divisadero Sts., Marina District.
October 7, 2019

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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