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

Filter Total Items: 416
Date published: October 23, 2019
Status: Active

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

Landslides in the San Francisco Bay area (SFBA) of California impact people, infrastructure, and the environment, and are commonly induced by intense or prolonged rainfall associated with strong winter storms...

Contacts: Brian Collins
Date published: October 23, 2019
Status: Active

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

Landslides in the San Francisco Bay area (SFBA) of California impact people, infrastructure, and the environment, and are commonly induced by intense or prolonged rainfall associated with strong winter storms...

Contacts: Brian Collins
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-...

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...

Date published: October 17, 2019
Status: Active

CoSMoS 3.1: Central California

CoSMoS v3.1 for central California shows projections for future climate scenarios (sea-level rise and storms)

Date published: October 14, 2019
Status: Active

Topobathymetric Elevation Model of San Francisco Bay Area, California

Accurate, high-resolution elevation information is vital to understanding the natural hazards that can impact the highly populated San Francisco Bay area, such as sea-level rise, winter storms, cliff erosion, and other coastal hazards. The San Francisco Bay estuary three-dimensional (3D) topobathymetric digital elevation model (TBDEM) was developed in collaboration between ...

Date published: October 8, 2019
Status: Completed

Earthquake Early Warning – Fine-Tuning for Best Alerts

The goal of an earthquake early warning (EEW) system is to provide an alert to people and automatic systems after an earthquake begins but before the shaking reaches their location. As the USGS and its partners are developing an EEW system, called ShakeAlert®, for the West Coast, the benefits, costs, capabilities, and limitations are being investigated. Two recent studies explored the...

Date published: September 30, 2019
Status: Completed

Could the M7.1 Ridgecrest, CA Earthquake Sequence Trigger a Large Earthquake Nearby?

Release Date: SEPTEMBER 30, 2019

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?”.

Date published: August 26, 2019
Status: Completed

Loma Prieta Earthquake Professional Papers

The four Loma Prieta Earthquake Professional Papers, which were published as multiple chapters, comprehensively document the magnitude 6.9 earthquake in California that shook the San Francisco and Monterey Bay regions on October 17, 1989. They contain almost 3000 pages written by 401 investigators of the earthquake. The investigations were funded by a special Congressional appropriation to the...

Date published: August 21, 2019
Status: Active

Directions

Information to help you plan your visit to the Earthquake Science Center.

Date published: August 5, 2019
Status: Completed

M7.9 1857 Fort Tejon Earthquake

The Last "Big One" in Southern California.

Date published: August 5, 2019
Status: Completed

M6.9 October 17, 1989 Loma Prieta Earthquake

On October 17, 1989, at 5:04:15 p.m. (PDT), a magnitude 6.9 earthquake severely shook the San Francisco and Monterey Bay regions. The epicenter was located near Loma Prieta peak in the Santa Cruz Mountains, approximately 14 km (9 mi) northeast of Santa Cruz and 96 km (60 mi) south-southeast of San Francisco.

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Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 ocean-currents projections: average conditions 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

Date published: May 4, 2020

CoSMoS (Coastal Storm Modeling System) Central California v3.1 wave-hazard projections: 20-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

Date published: April 30, 2020

Quaternary faults offshore of California

A comprehensive map of Quaternary faults has been generated for offshore of California. The Quaternary fault map includes mapped geometries and attribute information for offshore fault systems located in California State and Federal waters. The polyline shapefile has been compiled from previously published mapping where relatively dense, high-resolution marine geophysical data exist. The data...

Date published: April 30, 2020

Select borehole data for Anza Valley, Anza, CA

Borehole log number, State Well Number, location, construction information, and any wells tests performed on select wells from the Anza basin, Anza, CA. Also includes a lithologic data for a sub-set of borehole logs identified based on best coverage and representation of data within the study area.

Date published: April 29, 2020

Partitioning of six pyrethroid insecticides at varying salinities

To determine aqueous pyrethroid partitioning across a salinity gradient 20 mL Pyrex beakers were filled with 8 mL of deionized water at varying salinities (0, 0.5, 2, 6 ppt). Salinity was adjusted using a 10 ppt stock solution (made by diluting Instant Ocean into deionized water). The water samples were spiked with pyrethroids (bifenthrin, cyhalothrin, cyfluthrin, cypermethr

Date published: April 29, 2020

SmeltCam sampling in San Joaquin River and False River near Jersey Island in the Sacramento-San Joaquin River Delta, California, 2016

This dataset includes field data for fishes sampled using mid-water trawls and the SmeltCam during daylight hours in the Sacramento- San Joaquin Delta, California. Sampling took place between February 8, 2016 and March 1, 2016. This data release includes all measured environmental parameters and fish taxa collected during sampling event.

Date published: April 28, 2020

Otolith chemistry of fishes in Rodeo Lagoon, Marin County, California, 2016

The dataset includes multiple file types (CSV, ArcGIS shapefiles, and images), data relates to the elemental analysis of fish otoliths. Otoliths examined in this study were from randomly-sampled individual Tidewater Goby (Eucyclogobius newberryi) and Prickly Sculpin (Cottus asper) from the adult population of Rodeo Lagoon and Rodeo Creek, Marin County, California. The fish w

Date published: April 23, 2020

Domestic Wells in the United States

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. 

Date published: April 23, 2020

2018 San Gabriel Reach Habitat Data

This dataset includes reach habitat data for the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) in the San Gabriel River.

Date published: April 23, 2020

Groundwater-Quality Data in the Redding-Red Bluff Shallow Aquifer Study Unit, 2018-2019: Tables

The U.S. Geological Survey collected groundwater samples from 50 wells used for domestic and small system drinking water supplies in Shasta and Tehama Counties, California in 2018-2019. The wells were sampled for the Redding-Red Bluff Shallow Aquifer Study Unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin P...

Date published: April 23, 2020

2019 Santa Ana Reach Location Information

This dataset includes the 2019 latitude and longitude information for habitat and fish reach locations on the Santa Ana River.

Date published: April 23, 2020

Boundaries and Grid Cells of the Redding-Red Bluff Shallow Aquifer Study Unit, 2018-2019

The U.S. Geological Survey collected groundwater samples from 50 wells used for domestic and small-system drinking water supplies in Shasta and Tehama Counties, California in 2018-2019. The wells were sampled for the Redding-Red Bluff Shallow Aquifer study unit of the California State Water Resources Control Board Groundwater Ambient Monitoring and Assessment (GAMA) Program Priority Basin P...

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Year Published: 2018

Analysis of mean seismic ground motion and its uncertainty based on the UCERF3 geologic slip rate model with uncertainty for California

The Uniform California Earthquake Rupture Forecast v.3 (UCERF3) model (Field et al., 2014) considers epistemic uncertainty in fault‐slip rate via the inclusion of multiple rate models based on geologic and/or geodetic data. However, these slip rates are commonly clustered about their mean value and do not reflect the broader distribution of...

Zeng, Yuehua
Zeng, Y. (2018). Analysis of Mean Seismic Ground Motion and Its Uncertainty Based on the UCERF3 Geologic Slip Rate Model with Uncertainty for California, SRL, doi: 10.1785/0220170114.

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Year Published: 2018

Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA

We investigated the benthic foraminiferal faunal and stable carbon and oxygen isotopic composition of a 15-cm push core (NA075-092b) obtained on a Telepresence-Enabled cruise to the Southeast Seep on Kimki Ridge offshore southern California. The seep core was taken at a depth of 973 m in the vicinity of a Beggiatoa bacterial mat and vesicomyid...

McGann, Mary; Conrad, James E.
McGann, M., Conrad, J.E., 2018, Faunal and stable isotopic analyses of benthic foraminifera from the Southeast Seep on Kimki Ridge offshore southern California, USA: Deep Sea Research Part II: Topical Studies in Oceanography, https://doi.org/10.1016/j.dsr2.2018.01.011

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Year Published: 2018

Estimation of stream conditions in tributaries of the Klamath River, northern California

Because of their critical ecological role, stream temperature and discharge are requisite inputs for models of salmonid population dynamics. Coho Salmon inhabiting the Klamath Basin spend much of their freshwater life cycle inhabiting tributaries, but environmental data are often absent or only seasonally available at these locations. To address...

Manhard, Christopher V.; Som, Nicholas A.; Jones, Edward C.; Perry, Russell W.
Manhard, C.V., N.A. Som, E.C. Jones, and R.W. Perry. 2018. Estimation of stream conditions in tributaries of the Klamath River, Northern California. U.S. Fish and Wildlife Service. Arcata Fish and Wildlife Office, Arcata Fisheries Technical Report Number TR 2018-32, Arcata, California.

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Year Published: 2018

Effects of the proposed California WaterFix North Delta Diversion on survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento-San Joaquin River Delta, northern California

The California Department of Water Resources and Bureau of Reclamation propose new water intake facilities on the Sacramento River in northern California that would convey some of the water for export to areas south of the Sacramento-San Joaquin River Delta (hereinafter referred to as the Delta) through tunnels rather than through the Delta. The...

Perry, Russell W.; Pope, Adam C.
Perry, R.W., and Pope, A.C., 2018, Effects of the proposed California WaterFix North Delta Diversion on survival of juvenile Chinook salmon (Oncorhynchus tshawytscha) in the Sacramento-San Joaquin River Delta, northern California: U.S. Geological Survey Open-File Report 2018-1078, 94 p. plus appendixes, https://doi.org/10.3133/ofr20181078.

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Year Published: 2018

Estimating fluvial discharges coincident with 21st century coastal storms modeled with CoSMoS

On the open coast, flooding is largely driven by tides, storm surge, waves, and in areas near coastal inlets, the magnitude and co-occurrence of high fluvial discharges. Statistical methods are typically used to estimate the individual probability of coastal storm and fluvial discharge occurrences for use in sophisticated flood hazard models. A...

Erikson, Li H.; O'Neill, Andrea C.; Barnard, Patrick L.
Erikson, L.H., O’Neill, A.C., and Barnard, P.L., 2018. Estimating fluvial discharges coincident with 21st century coastal storms modeled with CoSMoS. In: Shim, J.S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). J. of Coastal Research, Special Issue No. 85, pp. 1–5. Coconut Creek (Florida), ISSN 0749-0208.

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Year Published: 2018

Juvenile Lost River and shortnose sucker year class strength, survival, and growth in Upper Klamath Lake, Oregon, and Clear Lake Reservoir, California—2016 Monitoring Report

Executive SummaryThe largest populations of federally endangered Lost River (Deltistes luxatus) and shortnose suckers (Chasmistes brevirostris) exist in Upper Klamath Lake, Oregon, and Clear Lake Reservoir, California. Upper Klamath Lake populations are decreasing because adult mortality, which is relatively low, is not being balanced by...

Burdick, Summer M.; Ostberg, Carl O.; Hoy, Marshal S.
Burdick, S.M., Ostberg, C.O., and Hoy, M.S., 2018, Juvenile Lost River and shortnose sucker year class strength, survival, and growth in Upper Klamath Lake, Oregon, and Clear Lake Reservoir, California—2016 Monitoring Report: U.S. Geological Survey Open-File Report 2018–1066, 43 p., https://doi.org/10.3133/ofr20181066.

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Year Published: 2018

N-mix for fish: estimating riverine salmonid habitat selection via N-mixture models

Models that formulate mathematical linkages between fish use and habitat characteristics are applied for many purposes. For riverine fish, these linkages are often cast as resource selection functions with variables including depth and velocity of water and distance to nearest cover. Ecologists are now recognizing the role that detection plays in...

Som, Nicholas A.; Perry, Russell W.; Jones, Edward C.; De Juilio, Kyle; Petros, Paul; Pinnix, William D.; Rupert, Derek L.
Som, N.A., R.W. Perry, E.C. Jones, K. De Juilio, P. Petros, W.D. Pinnix, and D.L. Rupert. 2017. N-mix for fish: estimating riverine salmonid habitat selection via N-mixture models. Can. J. Fish and Aquat. Sci., Published on the web 07 September 2017.

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Year Published: 2018

Effects of the proposed California WaterFix North Delta Diversion on flow reversals and entrainment of juvenile Chinook salmon (Oncorhynchus tshawytscha) into Georgiana Slough and the Delta Cross Channel, northern California

The California Department of Water Resources and Bureau of Reclamation propose new water intake facilities on the Sacramento River in northern California that would convey some of the water for export to areas south of the Sacramento-San Joaquin River Delta (hereinafter referred to as the Delta) through tunnels rather than through the Delta. The...

Perry, Russell W.; Romine, Jason G.; Pope, Adam C.; Evans, Scott D.
Perry, R.W., Romine, J.G., Pope, A.C., and Evans, S.D., 2018, Effects of the proposed California WaterFix North Delta Diversion on flow reversals and entrainment of juvenile Chinook salmon (Oncorhynchus tshawytscha) into Georgiana Slough and the Delta Cross Channel, northern California: U.S. Geological Survey Open File Report 2018-1028, 46 p., https://doi.org/10.3133/ofr20181028.

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Year Published: 2018

Clayey landslide initiation and acceleration strongly modulated by soil swelling

Largely unknown mechanisms restrain motion of clay-rich, slow-moving landslides that are widespread worldwide and rarely accelerate catastrophically. We studied a clayey, slow-moving landslide typical of thousands in northern California, USA, to decipher hydrologic-mechanical interactions that modulate landslide dynamics. Similar to some other...

Schulz, William; Smith, Joel B.; Wang, Gonghui; Jiang, Yao; Roering, Joshua J.

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Year Published: 2018

Variability in soil-water retention properties and implications for physics-based simulation of landslide early warning criteria

Rainfall-induced shallow landsliding is a persistent hazard to human life and property. Despite the observed connection between infiltration through the unsaturated zone and shallow landslide initiation, there is considerable uncertainty in how estimates of unsaturated soil-water retention properties affect slope stability assessment. This source...

Thomas, Matthew A.; Mirus, Benjamin B.; Collins, Brian D.; Lu, Ning; Godt, Jonathan W.
Thomas MA, Mirus BB, Collins BD, Lu N, and Godt JW (2018) Variability in soil-water retention properties and implications for physics-based simulation of landslide early warning criteria, Landslides. https://doi.org/10.1007/s10346-018-0950-z

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Year Published: 2018

Earthquake potential in California-Nevada implied by correlation of strain rate and seismicity

Rock mechanics studies and dynamic earthquake simulations show that patterns of seismicity evolve with time through (1) accumulation phase, (2) localization phase, and (3) rupture phase. We observe a similar pattern of changes in seismicity during the past century across California and Nevada. To quantify these changes, we correlate GPS strain...

Zeng, Yuehua; Petersen, Mark D.; Shen, Zheng-Kang
Zeng, Y., Petersen, M. D., & Shen, Z.-K.(2018). Earthquake potential in California-Nevada implied by correlation of strain rate and seismicity. Geophysical Research Letters, 45. https://doi.org/10.1002/2017GL075967

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Year Published: 2018

Seafloor fluid seeps on Kimki Ridge, offshore southern California: Links to active strike-slip faulting

The Kimki Ridge fluid seeps are located in western Catalina Basin about 60 km southwest of the southern California mainland and at a water depth of approximately 1100 m. Multichannel seismic reflection profiles collected by the U.S. Geological Survey (USGS) in 2014 show acoustic transparency within the Kimki...

Conrad, James E.; Prouty, Nancy G.; Walton, Maureen A. L.; Kluesner, Jared W.; Maier, Katherine L.; McGann, Mary; Brothers, Daniel; Roland, Emily C.; Dartnell, Peter

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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. 

November 21, 2019

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
November 14, 2019

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.

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
...
A smiling woman in a hard hat and life jacket gives two-thumbs-up on the deck of a ship standing next to a sediment core tube.
October 31, 2019

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 

...
An instrument rests on the deck of a ship, its cables suspended above it, while a scientist looks on.
October 22, 2019

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.

View from up high on a coastal cliff looking down along a beach where a river meets the ocean.
October 17, 2019

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.

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

People standing on the stern of a boat out in open, calm water, sun low in the sky behind clouds.
October 16, 2019

Retrieving gear from off the coast

A science crew on M/V (marine vessel) Bold Horizon retrieve gear from offshore San Francisco.

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Screenshot Location of Coso volcanic field
July 6, 2019

An earthquake swarm started on the evening of July 5 at the southern margin of Coso Volcanic Field in Inyo County, California.

Giant gartersnake (Thamnophis gigas)
June 24, 2019

SACRAMENTO – A new study shows how giant gartersnakes use Central Valley rice fields

USGS Scientists taking sediment core at Six Gill Slough restored marsh.
June 6, 2019

California Water Science Center Research Hydrologist Dr. Judith Drexler and others have published an article in the journal Restoration Ecology, observing the progress of a restored salt marsh in southern Puget Sound, Washington.

SEDHYD Conference Image
May 17, 2019

California Water Science Center (CAWSC) hydrologists Joseph Hevesi, Scott Wright, Alexandra Etheridge, Mathieu Marineau, and Michelle Stern will discuss their research at the 2019 Federal Interagency Sedimentation and Hydrologic Modeling (SEDHYD) Conference in Reno, Nevada.

A scene showing the harbor and surrounds at Monaco, Monte Carlo
May 16, 2019

Dr. Christina Kellogg (Research Microbiologist, SPCMSC) is a member of the judging panel that will award winners of the $7 million dollar Shell Ocean Discovery XPRIZE during the final award announcement at the Musée Océanographique de Monaco on May 31.

A huge canyon surrounded by deep-set cliffs opens to reveal a sunny gorge and part of the Colorado River.
April 11, 2019

A new study shows that mysterious cycles in salinity in the lower Colorado River are a result of precipitation patterns in the headwaters of the upper basin more than a thousand river miles away. The salinity levels generally repeat about every 10 years.

Rear-arc basalt lava outcrop
April 2, 2019

Scientists at the volcano observatories of the U.S. Geological Survey pay close attention to volcanoes of the Cascade Range, Alaskan Peninsula and Aleutian Arc.

waves cross a coastal road
March 29, 2019

In less than 30 years the combination of sea-level rise plus an extreme storm along California’s coast could flood more than 150,000 residents and impact over $30 billion in property value. By 2100, up to 600,000 people and $150 billion in property could be at risk from coastal flooding.

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