Janet Watt
My research focuses on characterizing onshore/offshore geologic structure, deformation, and active tectonics to address problems focused on geologic hazards and framework geologic processes. My recent work involves the development and application of integrative geophysical approaches to 3D characterization of faults and fault interactions.
Biography
I received my M.S. in Marine Science (Geological Oceanography) from Moss Landing Marine Laboratories while working at the USGS in Menlo Park, CA. As part of the Geophysical Unit of Menlo Park (GUMP), I used potential-field methods (gravity and magnetics) and 3D geologic mapping to understand earthquake and volcano hazards, and mineral and water resources in the western U.S. In 2010, I returned to my marine geology roots and joined the Pacific Coastal and Marine Science Center in Santa Cruz, CA where I currently work as a Research Geophysicist.
Selected Media and Public Outreach
November 18, 2016, CBS This Morning "California prepares for next big earthquake"
October 19, 2016, Popular Mechanics "Two dangerous Fault Lines Under San Francisco Are Connected, Study Finds"
February 1, 2016, Temblor.net Earthquake News & Blog, "Why don't the earthquakes line up with the San Andreas fault?"
January 2, 2016, CBS NEWS, "Alarming Discovery Shows Bay Area’s 2 Most Dangerous Earthquake Faults May Be Connected"
December 31, 2015, San Francisco Chronicle, "New data on 2 Bay Area faults cause worry about next big quake"
November 20, 2014, KQED Science "Using 3D Visualization, Geologists Explore the Complex Areas Where Faults Join and Split"
Science and Products
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.
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...
2019 Seafloor Geodesy cruise
Performed maintenance on and retrieved data from seafloor geodetic instrument arrays offshore of Oregon and northern California in 2019, a USGS-Scripps-University of Washington-University of Hawaii partnership
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
2018 USGS-NOAA multibeam bathymetry surveys
Multibeam bathymetric surveys conducted offshore of Oregon and northern California in 2018, a USGS-NOAA partnership
Offshore Faults along Central and Northern California
From Point Conception to Cape Mendocino, seafloor faults have been, in the past, mapped in varying ways and without enough detail to assess their earthquake potential. To provide this important information, USGS uses advanced technology to image offshore faults that could trigger devastating earthquakes near densely populated areas and a nuclear power plant.
Margin-wide geological and geophysical synthesis to understand the recurrence and hazards of great subduction zone earthquakes in Cascadia
The Cascadia Subduction Zone, located in the U.S. Pacific Northwest and southwestern British Columbia, has hosted magnitude ≥8.0 megathrust earthquakes in the geologic past, a future earthquake is imminent, and the potential impacts could cripple the region. Subduction zone earthquakes represent some of the most devastating natural hazards on Earth. Despite substantial knowledge gained from...
Composite multibeam bathymetry surface and data sources of the southern Cascadia Margin offshore Oregon and northern California
Bathymetry data from various sources, including newly released 2018 and 2019 multibeam data collected by NOAA and the USGS, were combined to create a composite 30-m resolution multibeam bathymetry surface of the southern Cascadia Margin offshore of Oregon and northern California. The bathymetry data are available as a 30-m resolution geoTIFF file, accompanied by a polygon shapefile
Geophysical and core sample data collected offshore San Francisco, California, during field activity 2019-649-FA from 2019-10-11 to 2019-10-18
USGS collected geophysical and core sample data aboard R/V Bold Horizon in 2019 on cruise 2019-649-FA offshore San Francisco, California. The data were collected to assess sand and gravel resources in Federal and State waters for potential use in future beach nourishment projects along stretches of the coast where critical erosion hotspots have been identified. This cruise was funded through...
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
Multichannel minisparker, multichannel boomer, and chirp seismic-reflection data of USGS field activity 2017-612-FA collected in Puget Sound and Lake Washington in February of 2017
High-resolution multichannel minisparker, multichannel boomer and chirp seismic-reflection data were collected by the U.S. Geological Survey and the University of Washington in February of 2017 west of Seattle in Puget Sound and in Lake Washington, Washington. Data were collected aboard University of Washington's R/V Clifford A. Barnes during USGS field activity 2017-612-FA.
Chirp sub-bottom data of USGS field activity K0211PS collected in Puget Sound, Washington in April of 2011
High-resolution chirp sub-bottom data were collected by the U.S. Geological Survey in April 2011 south of Bainbridge Island and west of Seattle in Puget Sound, Washington. Data were collected aboard R/V Karluk during field activity K0211PS using an Edgetech SB-512i sub-bottom profiler. Sub-bottom acoustic penetration spans several tens of meters and is variable by location.
Multichannel sparker seismic reflection data of USGS field activity 2018-658-FA collected between Cape Blanco and Cape Mendocino from 2018-10-04 to 2018-10-18
This data release contains processed high-resolution multichannel sparker seismic-reflection (MCS) data that were collected aboard Humboldt State University’s R/V Coral Sea in October of 2018 on U.S. Geological Survey cruise 2018-658-FA on the shelf and slope between Cape Blanco, Oregon, and Cape Mendocino, California. MCS data were collected to characterize quaternary deforma
California State Waters Map Series Data Catalog--Point Sur to Point Arguello Region
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.
Marine magnetic data from Point Sur to Piedras Blancas, central California, 2011
This dataset includes marine magnetic data collected by the U.S. Geological Survey (USGS) in 2011 during field activity B-05-11-CC between Point Sur and Piedras Blancas, central California.
Chirp seismic-reflection data: San Pablo Bay, California
This data release includes chirp seismic-reflection data collected in 2014 aboard the USGS R/V Snavely in San Pablo Bay, part of northern San Francisco Bay. The data were collected as part of USGS efforts to better understand the fault geometry of the Hayward and Rodgers Creek faults beneath the bay.
Toward an integrative geological and geophysical view of Cascadia subduction zone earthquakes
The Cascadia subduction zone (CSZ) is an exceptional geologic environment for recording evidence of land level changes, tsunamis, and ground motion that reveals at least 19 great megathrust earthquakes over the past 10 kyr. Such earthquakes are among the most impactful natural hazards on Earth, transcend national boundaries, and can have global...
Walton, Maureen A. L.; Staisch, Lydia M.; Dura, Tina; Pearl, Jessie Kathleen; Sherrod, Brian; Gomberg, Joan S.; Engelhart, Simon E.; Trehu, Anne; Watt, Janet; Perkins, Jonathan P; Witter, Robert C.; Bartlow, Noel; Goldfinger, Chris; Kelsey, Harvey; Morey, Ann; Sahakian, Valerie J.; Tobin, Harold; Wang, Kelin; Wells, Ray; Wirth, Erin Systematic 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, Daniel Submarine canyons, slope failures and mass transport processes in southern Cascadia
The marine turbidite record along the southern Cascadia Subduction Zone has been used to interpret paleoseismicity and suggest a shorter recurrence interval for large (>M7) earthquakes along this portion of the margin; however, the sources and pathways of these turbidity flows are poorly constrained. We examine the spatial distribution of...
Hill, Jenna C.; Watt, Janet; Brothers, Daniel; Kluesner, Jared Controls on sediment distribution in the coastal zone of the central California transform continental margin, USA
We use >10,000 km of high-resolution seismic-reflection data together with multibeam bathymetry to document complex and highly variable post-Last Glacial Maximum (LGM) sediment distribution and thickness in the coastal zone (~10 m isobath to 5.6 km offshore) along a ~800 km section of central California's transform...
Johnson, Samuel Y.; Beeson, Jeffrey W.; Watt, Janet; Sliter, Ray; Papesh, Antoinette Plate boundary localization, slip-rates and rupture segmentation of the Queen Charlotte Fault based on submarine tectonic geomorphology
Linking fault behavior over many earthquake cycles to individual earthquake behavior is a primary goal in tectonic geomorphology, particularly across an entire plate boundary. Here, we examine the 1150-km-long, right-lateral Queen Charlotte-Fairweather fault system using comprehensive multibeam bathymetry data acquired along the Queen Charlotte...
Brothers, Daniel; Miller, Nathaniel C.; Vaughn Barrie; Haeussler, Peter; H. Gary Greene; Andrews, Brian D.; Olaf Zielke; Dartnell, Peter
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.
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 Neotectonics of the Big Sur Bend, San Gregorio‐Hosgri fault system, central California
The right‐lateral San Gregorio‐Hosgri fault system (SGHF) extends mainly offshore for about 400 km along the central California coast and is a major structure in the distributed transform margin of western North America. We mapped a poorly known 64‐km‐long section of the SGHF offshore Big Sur between Piedras Blancas and Point Sur using high‐...
Johnson, Samuel Y.; Watt, Janet; Hartwell, Stephen; Kluesner, Jared
Reducing risk where tectonic plates collide—U.S. Geological Survey subduction zone science plan
The U.S. Geological Survey (USGS) serves the Nation by providing reliable scientific information and tools to build resilience in communities exposed to subduction zone earthquakes, tsunamis, landslides, and volcanic eruptions. Improving the application of USGS science to successfully reduce risk from these events relies on whole community efforts...
Gomberg, Joan S.; Ludwig, K.A.; Bekins, Barbara; Brocher, Thomas M.; Brock, John; Brothers, Daniel; Chaytor, Jason D.; Frankel, Arthur; Geist, Eric L.; Haney, Matthew M.; Hickman, Stephen H.; Leith, William S.; Roeloffs, Evelyn A.; Schulz, William H.; Sisson, Thomas W.; Wallace, Kristi L.; Watt, Janet; Wein, Anne M. The California Seafloor and Coastal Mapping Program – Providing science and geospatial data for California's State Waters
The California Seafloor and Coastal Mapping Program (CSCMP) is a collaborative effort to develop comprehensive bathymetric, geologic, and habitat maps and data for California's State Waters. CSCMP began in 2007 when the California Ocean Protection Council (OPC) and the National Oceanic and Atmospheric Administration (NOAA) allocated funding for...
Johnson, Samuel Y.; Cochrane, Guy R.; Golden, Nadine; Dartnell, Peter; Hartwell, Stephen; Cochran, Susan A.; Watt, Janet Missing link between the Hayward and Rodgers Creek faults
The next major earthquake to strike the ~7 million residents of the San Francisco Bay Area will most likely result from rupture of the Hayward or Rodgers Creek faults. Until now, the relationship between these two faults beneath San Pablo Bay has been a mystery. Detailed subsurface imaging provides definitive evidence of active faulting along the...
Watt, Janet; Ponce, David A.; Parsons, Thomas E.; Hart, Patrick E.
California State Waters Map Series—Offshore of Monterey, California
IntroductionIn 2007, the California Ocean Protection Council initiated the California Seafloor Mapping Program (CSMP), designed to create a comprehensive seafloor map of high-resolution bathymetry, marine benthic habitats, and geology within the 3-nautical-mile limit of California’s State Waters. The CSMP approach is to create highly detailed...
Johnson, Samuel Y.; Cochran, Susan A.; Johnson, Samuel Y.; Dartnell, Peter; Hartwell, Stephen R.; Cochrane, Guy R.; Golden, Nadine E.; Watt, Janet T.; Davenport, Clifton W.; Kvitek, Rikk G.; Erdey, Mercedes D.; Krigsman, Lisa M.; Sliter, Ray W.; Maier, Katherine L.
Unlocking plate motions of the Cascadia subduction zone with seafloor geodesy
Seeking understanding of the fundamental constraints on plate motions, rates of convergence, and shallow strain accumulation across one of the United States’ most hazardous fault zones.
PCMSC scientists invited to present at the National Seismic Hazard Map Workshop
USGS Pacific Coastal and Marine Science Center research geologist Jenna Hill to present recent offshore work on the Cascadia Subduction Zone.
Earthquakes, Landslides, and Tsunamis: Mapping Geohazards in the Cascadia Subduction Zone
The geologic research and mapping in the offshore areas is foundational to understanding how to manage resources and improve public safety in subduction zone areas.
USGS-NOAA cruise maps Cascadia subduction zone to assess earthquake hazards
From July 31 to August 23, a joint USGS-NOAA cruise mapped seafloor depths, texture, and gas seeps in the Cascadia subduction zone offshore of Washington, Oregon, and northern California.
Mystery Gap: Connecting Earthquake Faults near San Francisco, California, Requires Many Approaches
New USGS mapping studies in San Pablo Bay, California, show that two of the region’s earthquake faults—the Hayward and Rodgers Creek faults—connect beneath the bay.
CBS This Morning features USGS scientists studying link between earthquake faults near San Francisco, California
Coring the Hayward-Rodgers Creek fault zone in San Pablo Bay, California, to unravel the history of faulting beneath the bay
