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
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.
Continuous, Real-Time Water-Quality Monitoring of the Los Angeles River
As part of the Urban Waters Federal Partnership (UWFP) program, this project will bring enhanced water-quality monitoring to a stretch of the Los Angeles River slated for revitalization. The UWFP reconnects urban...
Cascadia Subduction Zone Marine Geohazards
Societal Issue: Uncertainty related to rupture extent, slip distribution, and recurrence of past subduction megathrust earthquakes in the Pacific Northwest (northern CA, OR, WA, and southern BC) leads to ambiguity in earthquake and tsunami hazard assessments and hinders our ability to prepare for future events.
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.
January 2021: Evaluation of debris flow activity in recent California Burn Areas following atomospheric river event
The January 2021 atmospheric river event produced heavy rainfall in some areas burned by wildfires in 2020. The Landslide Hazards Program (LHP) staff has evaluated the debris-flow activity in several areas. The locations are: The Carmel Fire, the CZU Lightning Complex Fire (San Mateo and Santa Cruz), the Dolan Fire, and the River Fire burn areas.
Reports by date are below. Photos will...
Longfin Smelt Distribution in the Coastal Pacific Ocean
Longfin Smelt (Spirinchus thaleichthys) is a pelagic fish species found in waters along the Pacific coast, from Alaska to central California. Its complex life cycle makes it vulnerable to threats in both freshwater and at sea. Longfin Smelt is listed as a threatened species by the state of California.
Big Sur Landslides
On California’s Big Sur coast, the steep slopes at Mud Creek suffered a catastrophic collapse (May 20, 2017). On January 28, 2021, heavy rains from a two-day storm caused debris from fire-scarred slopes to wash out another section of road at Rat Creek. USGS scientists are monitoring this 100-mile section of the California coastline, in collaboration with the CA Department of Transportation....
The Mud Creek Landslide May 20 2017
On May 20, 2017, the steep slopes at Mud Creek on California’s Big Sur coast, about 140 miles south of San Francisco, suffered a catastrophic collapse. USGS scientists from the Pacific Coastal and Marine Science Center and the Geology, Minerals, Energy, and Geophysics Science Center continue to monitor this section of the coastline, in collaboration with the California Department of...
Dynamic coastlines along the western U.S.
The west coast of the United States is extremely complex and changeable because of tectonic activity, mountain building, and land subsidence. These active environments pose a major challenge for accurately assessing climate change impacts, since models were historically developed for more passive sandy coasts.
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...
Assessing Sediment Nutrient Storage and Release in California's Sacramento-San Joaquin Delta
Sediments represent an important pool of nutrients in the Sacramento-San Joaquin Delta (Delta). The exchange of nutrients between the water column and the benthos impacts water quality and effects phytoplankton, harmful algal blooms, aquatic vegetation, and drinking water quality. To date, there is very limited information about nutrient pools in Delta sediments, nor how these nutrients are...
Sediment transport between estuarine habitats in San Francisco Bay
This research is part of the project “Sediment Transport in Coastal Environments”
San Francisco Bay geomorphology
This research is part of the project “Sediment Transport in Coastal Environments”
Water Quality Samples for USGS 11092450 LOS ANGELES R A SEPULVEDA DAM CA
Water-quality data collected for various parameters at USGS monitoring site 11092450 (Los Angeles River at Sepulveda Dam).
Geophysical and sampling data collected offshore Oceanside, southern California during field activity 2017-686-FA from 2017-10-23 to 2017-10-31
This data release contains geophysical and sediment sample data that were collected aboard the R/V Snavely in 2017 on U.S. Geological Survey cruise 2017-686-FA offshore Oceanside, southern California. The goal of the survey was to provide high-resolution imaging, magnetic anomaly profiles and sediment analysis to characterize the surface and subsurface properties of the study area such as
Coastal Storm Modeling System (CoSMoS) for Central California, v3.1
CoSMoS v3.1 for Central California shows projections for future climate scenarios to provide emergency responders and coastal planners with critical storm-hazards information that can be used to increase public safety, mitigate physical damages, and more effectively manage and allocate resources within complex coastal settings. Data for Central California: Pt. Conception to Golden Gate Bridge...
Mud logs from the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS) in cooperation with the California State Water Resources Control Board (SWRCB) compiled and digitized mud logs from oil and gas wells in the Oxnard Oil Field area.
Fluid levels in the Oxnard Oil Field, Ventura County, California
The U.S. Geological Survey (USGS), in cooperation with the California State Water Resources Control Board (SWRCB), compiled Fall 2017 fluid level elevation data from idle oil and gas wells in the Oxnard Oil Field to estimate vertical hydraulic head difference between oil production and overlying groundwater aquifer zones.
Erodibility Data from Gust Erosion Chamber Experiments in Grizzly Bay and San Pablo Bay, California, Summer 2019
A Gust erosion chamber was used to apply horizontal shear stress to sediment cores obtained from San Pablo and Grizzly (within Suisun) Bays in California. A pair of sediment cores were collected from the same approximate locations in each bay six times between June 12th, 2019 and August 15th, 2019 for a total of 12 experiments and 24 sediment core results.
Verified Irrigated Agricultural Lands for the United States, 2002-17
The spatial extents of verified irrigated lands were compiled from various federal and state sources across the nation and combined into a single Geographic Information System (GIS) geodatabase for the purpose of model training and validation.
High-Resolution Measurements to Identify Effects of Aquatic Vegetation on Water Quality and Stratification
The dataset documents the spatial and temporal variability of nutrients and related water quality parameters at high spatial resolution in the North Delta of the Sacramento-San Joaquin River Delta of California, USA.
Insecticide and fungicide concentrations in irrigation runoff and soils from a lettuce field in the Salinas Valley, California, 2019 and 2020
Irrigation runoff and soil samples were collected from a lettuce field located at the USDA-ARS Spence Research farm in the Salinas Valley, California to measure neonicotinoid insecticides (clothianidin and imidacloprid) and a fungicide (azoxystrobin) applied via coated seed and drench treatments.
Water chemistry data for samples collected at groundwater sites near the Oxnard oil field, June 2017-August 2017, Ventura County, California
In cooperation with the California State Water Resources Control Board's oil and gas Regional Monitoring Program, the U.S. Geological Survey collected and analyzed groundwater and associated quality control (QC) samples during June 2017 - August 2017.
Hydrodynamic and sediment transport data from San Pablo Bay and Grizzly Bay, California, 2019
USGS scientists collected hydrodynamic and sediment-transport data at shallow water sites in San Pablo Bay and Grizzly Bay, in northern San Francisco Bay between June and November 2019. The data were collected to determine hydrodynamic forcing, bed roughness, suspended-sediment concentration, and physical properties of the sediment bed. This data release includes hydrodynamic and sediment...
Diets and Stable Isotopes of Fishes in Rodeo Lagoon, California, 2016-2017
This dataset includes lab data for fish, fish diets, and stable isotopes for fish tissue, vegetation, and invertebrates collected during daylight hours in the Rodeo Lagoon and Lake in Golden Gate National Recreation Area at the Pacific Coast, USA during 2016 and 2017. This data release includes all animal taxa, and isotope values included in the analysis.
Prediction of Flooding Now and Into the Future: a geonarrative on coastal storms
The USGS is conducting a comprehensive evaluation of groundwater resources of the Adelaida area. Use this map to explore the hydrogeology of the area, including land use, geology, and USGS hydrologic data by watershed or water management district.
This USGS geonarrative (Esri Story Map) summarizes the USGS response and findings after the M6.4 on July 4 and M7.1 on July 6, 2019 in Searles Valley, Southern California, and includes links to USGS research publications and data releases.
A data visualization exploring the relationship between nutrient distribution and phytoplankton under different conditions across the San Francisco Delta and Estuary. Assessing distribution and abundance aids understanding of how managing nutrient supplies affects aquatic food webs, helping managers evaluate the potential environmental benefits of future nutrient reduction efforts against costs.
Data visualization tool created for California's Bay-Delta Regional Monitoring Program. This web application visualizes nutrients and phytoplankton spatially and temporally for data collected in 2018.
RestoreNet is a networked ecological experiment on the cutting-edge of restoration science. The experiment sites span dryland ecoystems of the southwest U.S.
Domestic wells provide drinking water supply for approximately 40 million people in the United States. Knowing the location of these wells, and the populations they serve, is important for identifying heavily used aquifers, locations susceptible to contamination, and populations potentially impacted by poor-quality groundwater.
A geonarrative summary of the USGS report that provides a broad perspective on California’s exposure to volcanic hazards. By integrating volcanic hazard information with geospatial data on populations, infrastructure, and resources, the results provide estimates of impacts to people and our environment if an eruption were to occur.
The GAMA-PBP Public-Supply Well Results data viewer allows the user to visualize and download California water-quality data and trends for1974 - 2014. Groundwater-quality data for 38 inorganic constituents are captured and can be downloaded for individual sites or by grid cell.
Figure 4. Yearly Distribution (2007-2019) of Tamarisk Beetle (Diorhabda spp.). Annual tamarisk beetle distribution map. Provided by RiversEdge West. 2020. Used with permission from Ben Bloodgood, Program Coordinator.
The California Seafloor Mapping Program (CSMP) is a cooperative program to create a comprehensive coastal and marine geologic and habitat base map series for California's State waters. Initiated in 2008, the CSMP has collected bathymetry and backscatter data that are being turned into habitat and geologic base maps.
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 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.
Landscape evolution in eastern Chuckwalla Valley, Riverside County, California
This study investigates sedimentary and geomorphic processes in eastern Chuckwalla Valley, Riverside County, California, a region of arid, basin-and-range terrain where extensive solar-energy development is planned. The objectives of this study were to (1) measure local weather parameters and use them to model aeolian sediment-transport potential...
East, Amy E.; Gray, Harrison J.; Redsteer, Margaret Hiza; Ballmer, MatthewCharacterization of deep-sea coral and sponge communities in Greater Farallones National Marine Sanctuary: Point Arena South Essential Fish Habitat Conservation Area and New Amendment 28 Areas
This report summarizes samples collected during a remotely operated vehicle (ROV) cruise conducted in October 2019 on board E/V Nautilus. Areas sampled in Greater Farallones National Marine Sanctuary included areas proposed for fisheries management zoning in the Point Arena South (PAS) Essential Fish Habitat Conservation Area (EFH). Dive planning...
Graiff, Kaitlin; Roletto, Jan; Tezak, Sage; Williams, Gary E.; Cochrane, Guy R.Forecasting the frequency and magnitude of postfire debris flows across southern California
Southern California has a long history of damaging debris flows after wildfire. Despite recurrent loss, forecasts of the frequency and magnitude of postfire debris flows are not available for the region like they are for earthquakes. Instead, debris flow hazards are typically assessed in a reactive manner after wildfires. Such assessments are...
Kean, Jason W.; Staley, Dennis M.A geology and geodesy based model of dynamic earthquake rupture on the Rodgers Creek‐Hayward‐Calaveras Fault System, California
The Hayward fault in California's San Francisco Bay area produces large earthquakes, with the last occurring in 1868. We examine how physics‐based dynamic rupture modeling can be used to numerically simulate large earthquakes on not only the Hayward fault, but also its connected companions to the north and south, the Rodgers Creek and Calaveras...
Harris, Ruth A.; Barall, Michael; Lockner, David A.; Moore, Diane E.; Ponce, David A.; Graymer, Russell; Funning, Gareth J.; Morrow, Carolyn A.; Kyriakopoulos, Christodoulos; Eberhart-Phillips, DonnaThe weight of cities: Urbanization effects on Earth’s subsurface
Across the world, people increasingly choose to live in cities. By 2050, 70% of Earth's population will live in large urban areas. Upon considering a large city, questions arise such as, how much does that weigh? What are its effects on the landscape? Does it cause measurable subsidence? Here I calculate the weight of San Francisco Bay region...
Parsons, Thomas E.Toward physics-based nonergodic PSHA: A prototype fully-deterministic seismic hazard model for southern California
We present a nonergodic framework for probabilistic seismic‐hazard analysis (PSHA) that is constructed entirely of deterministic, physical models. The use of deterministic ground‐motion simulations in PSHA calculations is not new (e.g., CyberShake), but prior studies relied on kinematic rupture generators to extend empirical earthquake rupture...
Milner, Kevin R.; Shaw, Bruce E.; Goulet, Christine A.; Richards-Dinger, Keith B.; Callaghan, Scott; Jordan, Thomas H.; Dieterich, James H.; Field, Edward H.Juvenile Chinook salmon survival, travel time, and floodplain use relative to riverine channels in the Sacramento–San Joaquin River Delta
Floodplains provide multiple benefits to both resident and migratory fish species, including juvenile Chinook Salmon Oncorhynchus tshawytscha, but direct comparisons of survival during migration through a floodplain versus riverine routes are scarce. The Yolo Bypass is a broad floodplain of the Sacramento River that floods in about 30% of...
Pope, Adam; Perry, Russell; Harvey, Brett N.; Hance, Dalton; Hansel, Hal CThe impacts of the 2015/2016 El Niño on California's sandy beaches
The El Niño Southern Oscillation is the most dominant mode of interannual climate variability in the Pacific. The 2015/2016 El Niño event was one of the strongest of the last 145 years, resulting in anomalously high wave energy across the U.S. West Coast, and record coastal erosion for many California beaches. To better manage coastal resources,...
Smith, Schuyler A; Barnard, Patrick L.Characterizing strain between rigid crustal blocks in the southern Cascadia forearc: Quaternary faults and folds of the northern Sacramento Valley, California
Topographic profiles across late Quaternary surfaces in the northern Sacramento Valley (California, USA) show offset and progressive folding on series of active east- and northeast—trending faults and folds. Optically stimulated luminescence ages on deposits draping a warped late Pleistocene river terrace yielded differential incision rates along...
Angster, Stephen J.; Wesnousky, Steven G.; Figueiredo, Paula; Owen, Lewis A.; Sawyer, ThomasSystematic characterization of morphotectonic variability along the Cascadia convergent margin: Implications for shallow megathrust behavior and tsunami hazards
Studies of recent destructive megathrust earthquakes and tsunamis along subduction margins in Japan, Sumatra, and Chile have linked forearc morphology and structure to megathrust behavior. This connection is based on the idea that spatial variations in the frictional behavior of the megathrust influence the tectono-morphological evolution of...
Watt, Janet; Brothers, DanielCharacteristics of frequent dynamic triggering of microearthquakes in Southern California
Dynamic triggering of earthquakes has been reported at various fault systems. The triggered earthquakes are thought to be caused either directly by dynamic stress changes due to the passing seismic waves, or indirectly by other nonlinear processes that are initiated by the passing waves. Distinguishing these physical mechanisms is difficult...
Fan, Wenyuan; Barbour, Andrew; Cochran, Elizabeth S.; Lin, GuoqingSeismic attenuation monitoring of a critically stressed San Andreas fault
We show that seismic attenuation ( ) along the San Andreas fault (SAF) at Parkfield correlates with the occurrence of moderate‐to‐large earthquakes at local and regional distances. Earthquake‐related anomalies are likely caused by changes in permeability from dilatant static stress changes, damage by strong shaking from local...
Malagnini, Luca; Parsons, Thomas E.The Cliff Feature Delineation Tool scans digital elevation models (DEM) to delineate features on seacliffs like the cliff top, midline, toe, and convexities/concavities on the cliff face, outputting linear features as polylines and point shapefiles.
The MODLFOW One-Water Hydrologic Flow Model (MF-OWHM) (MF-OWHM; Boyce and others, 2020; Hanson and others, 2014) is a MODFLOW-2005-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.
Use this Groundwater Age Mixtures and Contaminant Trends Tool (GAMACTT) to explore the effects of basic aquifer properties and well configurations on groundwater age mixtures in groundwater discharge and on contaminant trends from varying nonpoint-source contaminant input scenarios.
An Excel® Workbook for Interpreting Groundwater Age Distributions from Environmental Tracer Data
Software to Process and Preserve Legacy Magnetotelluric Data from circa 1990 truck-mounted cross power and time series files in ASCII format.
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.
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.
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.
A Grid-Based, Distributed-Parameter Watershed Model to Estimate Net Infiltration Below the Root Zone
Terra MODIS & S-NPP VIIRS Observe Snowpack in Sierra Nevada Mt. Range
The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor is located aboard NASA’s Terra and Aqua satellites. The Visible Infrared Imaging Radiometer Suite (VIIRS) sensor is aboard the Suomi National Polar-orbiting Partnership (S-NPP) satellite. Together these sensors provide us with over two decades of crucial data for studying changes that have occurred on the
Image of the Week: Mudslide Cuts Through Big Sur Burn Scar
A mudslide near the 2020 Dolan Fire's ignition point chopped through a chunk of California's scenic State Highway 1 in late January.
The Dolan Fire began near Big Sur on August 18th, 2020. It scarred nearly 125,000 acres before being fully contained in December.
The damage is clear in false color Landsat 8 imagery from August and October. The scar is still
PubTalk 3/2021 - A Jaguar's Field of Dreams
Title: A Jaguar's Field of Dreams - If you build it, they will come (& other lessons from the U.S. - Mexico border) By: Laura M. Norman USGS, Western Geographic Science Center * Case study: the very lonely Jaguar * Madrean Archipelago Ecoregion, a biodiversity hotspot of the planet * Restoration ecohydrology and rewilding * Learn about the ecosystem services of rock
Burned, denuded hillside in the CZU Lightning Complex
The USGS landslide team monitors and continues to update the hazard map models based on data collected in burn areas. This information improves future models and provides better hazard assessments used by officials for emergency response and decision making. Many of the steep hillsides burned and denuded in California fires repel water rather than soak it in. This
...USGS Scientists Collect Water Quality Samples in the San Francisco Bay
USGS scientists collect water quality samples in the San Francisco Bay. The samples have been collected at the same locations for >50 years and are part of one of the longest running datasets of its kind in the United States. Sampling extends from the South San Francisco Bay at the Dumbarton bridge and ends in the Delta waterways in Antioch. Cruise days can last upwards
Examples of orthomosaic imagery and digital surface model
Examples of orthomosaic imagery and a high-resolution digital surface model of Post Point, Bellingham Bay, WA.
Los Angeles River at USGS Streamgage 11092450 near Sepulveda Dam
A concrete-lined stretch of the Los Angeles River that runs near Sepulveda Dam. USGS streamgage 11092450 can be seen in the lower left along the river wall. Restoration is planned for this stretch of the river that runs through the San Fernando Valley.
GeoEel on winch
The GeoEel is a multichannel digital streamer system, with hydrophones in a long, green hose. The streamer is towed in the water from a vessel like a long snake, and the hydrophones "listen" for and record the signals from the seismic sound source. Here, it is shown stored on its winch in the wareyard of MarFac, the USGS Pacific Coastal and Marine Science Center's marine
...Eagle Rock, California Debris Flow
Rilling and a shallow landslide in CZU Fire near Eagle Rock, California. Soil ~3 cm below surface was almost completely dry after the rain storm, highlighting soil water repellancy.
Sampling sediment following wildfires
In August of 2020, the enormous CZU wildfire complex consumed over 85,000 acres in San Mateo and Santa Cruz Counties, leaving scarred landscapes in the hilly region. Runoff from large rainstorms in the winter months carry contaminants from the soils within these burned-out forests. Forest fires and the fire retardants used to help control and extinguish them introduce
...Sampling sediment following wildfires
In August of 2020, the enormous CZU wildfire complex consumed over 85,000 acres in San Mateo and Santa Cruz Counties, leaving scarred landscapes in the hilly region. Runoff from large rainstorms in the winter months carry contaminants from the soils within these burned-out forests. Forest fires and the fire retardants used to help control and extinguish them introduce
...Sampling sediment following wildfires
In August of 2020, the enormous CZU wildfire complex consumed over 85,000 acres in San Mateo and Santa Cruz Counties, leaving scarred landscapes in the hilly region. Runoff from large rainstorms in the winter months carry contaminants from the soils within these burned-out forests. Forest fires and the fire retardants used to help control and extinguish them introduce
...CORVALLIS, ORE. – Reduction in wildlife mortality rates is sometimes cited as a potential benefit to the replacement of older, smaller turbines by larger, next generation turbines. In contrast, others have expressed concern that newer, larger turbines may actually increase bird and bat deaths.

Summary statistics are now available for this challenge. Thanks again to everyone who contributed!
The U.S. Geological Survey public lecture series is back and virtual. News reporters are invited to attend to learn how USGS scientists are helping protect one of the only jaguars that lives in the U.S.

Recent landslide activity along California’s Pacific coast in the region known as Big Sur has provided graphic examples of the power and impacts of natural hazard events.

This challenge is now complete! Thank you to everyone who contributed!
Fort Collins, CO – Considered one of the most imperiled ecosystems in the world and home to mule deer, pronghorn, sage-grouse, pygmy rabbits and more than 350 other species of conservation concern, the sagebrush ecosystem continues to shrink rapidly due to a host of growing threats, according to a new scientific report.

Volunteers contributed almost 800 edits toward this challenge since last week. This includes the removal of over 100 points that were either closed or represented the wrong feature type - NICE WORK!!

Volunteers continue to make progress on this challenge with almost 400 edits coming in since last week!

Summary statistics are now available for this challenge. Thanks again to everyone who contributed!

Multimedia documenting coastal change hazards research at the USGS
Southern California can now expect to see post-wildfire landslides occurring almost every year, with major events expected roughly every ten years, a new study led by U.S. Geological Survey researchers finds.

Volunteers contibuted over 300 edits since this challenge was launched last week. This includes the removal of points that are either closed or the wrong feature type. Thank you for helping to update The National Map!