James Conrad
I study seafloor geology along the West Coast of the U.S. using various types of geophysical surveys to map the seafloor and image sub-seafloor strata. The purpose of this work is to help understand the hazards posed to coastal communities and infrastructure by offshore active faults and submarine landslides.
Biography
I received a Bachelors Degree in Earth Science from U.C. Berkeley in 1981, and a Masters Degree in Geology from San Jose State University in 1993. I have worked at the USGS since 1981, first in the Minerals Program, where I worked to assess the potential for undiscovered mineral deposits in the western U.S., and used Argon geochronology to date mineral deposits and related igneous rocks. In 1995, I joined the Pacific Coastal and Marine Science Center, where I study marine geologic hazards such as earthquakes on offshore faults and tsunamis generated by submarine landslides.
Science and Products
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...
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 core sample data collected offshore Oceanside to San Diego, southern California, during field activity 2018-638-FA from 2018-05-21 to 2018-05-26
USGS collected geophysical and core sample data aboard R/V Bold Horizon in 2018 on cruise 2018-638-FA offshore Oceanside to San Diego, southern 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.
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
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...
Minisparker and chirp seismic-reflection data of field activity 2014-645-FA; offshore Santa Barbara, southern California from 2014-11-12 to 2014-11-25
USGS collected high-resolution multichannel minisparker and single-channel chirp seismic-reflection data in November 2014, in the offshore Catalina and Santa Cruz basins, which are surrounded by several of the southern California Channel Islands. The survey was designed to image areas of the seafloor associated with movement on the numerous faults offshore of southern California.
Minisparker and chirp seismic-reflection data of field activity 2014-645-FA; offshore Santa Barbara, southern California from 2014-11-12 to 2014-11-25
USGS collected high-resolution multichannel minisparker and single-channel chirp seismic-reflection data in November 2014, in the offshore Catalina and Santa Cruz basins, which are surrounded by several of the southern California Channel Islands. The survey was designed to image areas of the seafloor associated with movement on the numerous faults offshore of southern California.
Multichannel minisparker and chirp seismic reflection data of USGS field activity 2016-616-FA collected in the Catalina Basin offshore southern California in February 2016
This data release contains 25 multichannel minisparker seismic reflection (MCS) profiles and 41 chirp sub-bottom profiles collected in February of 2016 from the Catalina Basin offshore southern California by PCMSC in cooperation with the University of Washington. We collected data on R/V Thompson on USGS cruise 2016-616-FA. We collected MCS profiles to image the fault and channel...
Multibeam bathymetry and acoustic-backscatter data collected in 2016 in Catalina Basin, southern California and merged multibeam bathymetry datasets of the northern portion of the Southern California Continental Borderland
In February 2016 the University of Washington in cooperation with USGS PCMSC collected multibeam bathymetry and acoustic-backscatter data in and near the Catalina Basin, southern California aboard the University of Washington's Research Vessel Thomas G. Thompson. Data was collected using a hull-mounted Kongsberg EM300 multibeam...
Multichannel minisparker and chirp seismic-reflection data of field activity 2015-651-FA; Chatham Strait and Cross Sound, southeastern Alaska from 2015-08-03 to 2015-08-21
High-resolution multichannel minisparker and chirp seismic-reflection data were collected in August of 2015 to explore marine geologic hazards of inland waterways of southeastern Alaska. Sub-bottom profiles were acquired in the inland waters between Glacier Bay and Juneau, including Cross Sound and Chatham Strait.
Minisparker seismic-reflection data of field activity S-12-10-SC: Oceanside to La Jolla, offshore southern California from 2010-06-01 to 2010-06-12
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey area is offshore southern California between Oceanside and La Jolla. The data were collected aboard USGS R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic penetration spanned...
Minisparker seismic-reflection data of field activity S-07-11-SC: offshore San Diego, and Los Angeles Counties, southern California from 2011-06-08 to 2011-06-22
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2011 to collect information on active offshore faults. The survey area is offshore southern California between Long Beach and San Diego. The data were collected aboard USGS R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker system. Subbottom acoustic...
Colored shaded-relief bathymetry, acoustic backscatter, and selected perspective views of the northern part of the California Continental Borderland, southern California
The California Continental Borderland is the complex continental margin in southern California that extends from Point Conception southward into northern Baja California (Fisher and others, 2009). This colored shaded-relief bathymetry map of the northern continental borderland in southern California was generated primarily from multibeam-...
Dartnell, Peter; Roland, Emily C.; Raineault, Nicole A.; Castillo, Christopher M.; Conrad, James E.; Kane, Renato; Brothers, Daniel S.; Kluesner, Jared; Walton, Maureen A. L.
Focused fluid flow and methane venting along the Queen Charlotte fault, offshore Alaska (USA) and British Columbia (Canada)
Fluid seepage along obliquely deforming plate boundaries can be an important indicator of crustal permeability and influence on fault-zone mechanics and hydrocarbon migration. The ~850-km-long Queen Charlotte fault (QCF) is the dominant structure along the right-lateral transform boundary that separates the Pacific and North American tectonic...
Prouty, Nancy G.; Brothers, Daniel; Kluesner, Jared; Barrie, J. Vaughn; Andrews, Brian D.; Lauer, Rachel; Greene, Gary; Conrad, James E.; Lorenson, Thomas; Law, Michael D.; Sahy, Diana; Conway, Kim; McGann, Mary; Dartnell, Peter Morphology, structure, and kinematics of the San Clemente and Catalina faults based on high-resolution marine geophysical data, southern California Inner Continental Borderland
Catalina Basin, located within the southern California Inner Continental Borderland (ICB), is traversed by two active submerged fault systems that are part of the broader North America-Pacific plate boundary: the San Clemente fault (along with a prominent splay, the Kimki fault) and the Catalina fault. Previous studies have suggested that the San...
Walton, Maureen A. L.; Brothers, Daniel; Conrad, James E.; Maier, Katherine L.; Roland, Emily C.; Kluesner, Jared; Dartnell, Peter Commentary: Variability in shelf sedimentation in response to fluvial sediment supply and coastal erosion over the past 1,000 Years in Monterey Bay, CA, United States
A commentary on: Variability in Shelf Sedimentation in Response to Fluvial Sediment Supply and Coastal Erosion Over the Past 1,000 Years in Monterey Bay, CA, United States. by Carlin J., Addison J., Wagner A., Schwartz V., Hayward J., Severin V. (2019) Front. Earth Sci., 7:113. doi: 10.3389/feart.2019.00113
Warrick, Jonathan; East, Amy E.; Storlazzi, Curt D.; Conrad, James E. The Santa Cruz Basin submarine landslide complex, southern California: Repeated failure of uplifted basin sediment
The Santa Cruz Basin (SCB) is one of several fault-bounded basins within the California Continental Borderland that has drawn interest over the years for its role in the tectonic evolution of the region, but also because it contains a record of a variety of modes of sedimentary mass transport (i.e., open slope vs. canyon-confined systems). Here,...
Brothers, Daniel S.; Maier, Katherine L.; Kluesner, Jared W.; Conrad, James E.; Chaytor, Jason Slope failure and mass transport processes along the Queen Charlotte Fault Zone, western British Columbia
Multibeam echosounder (MBES) images, 3.5 kHz seismic-reflection profiles and piston cores obtained along the southern Queen Charlotte Fault Zone are used to map and date mass-wasting events at this transform margin – a seismically active boundary that separates the Pacific Plate from the North American Plate. Whereas the upper continental slope...
Greene, H. G.; Barrie, J. Vaughn; Brothers, Daniel; Conrad, James E.; Conway, Kim; East, Amy E.; Enkin, Randolph J.; Maier, Katherine L.; Walton, Maureen A. L.; Rohr, K .M. M. Slope failure and mass transport processes along the Queen Charlotte Fault, southeastern Alaska
The Queen Charlotte Fault defines the Pacific–North America transform plate boundary in western Canada and southeastern Alaska for c. 900 km. The entire length of the fault is submerged along a continental margin dominated by Quaternary glacial processes, yet the geomorphology along the margin has never been systematically examined due to the...
Brothers, Daniel; Andrews, Brian D.; Walton, Maureen A. L.; H. Gary Greene; J. Vaughn Barrie; Miller, Nathaniel C.; ten Brink, Uri S.; East, Amy E.; Haeussler, Peter J.; Kluesner, Jared W.; Conrad, James E. The tectonically controlled San Gabriel Channel–Lobe Transition Zone, Catalina Basin, Southern California Borderland
High-resolution geophysical data across the Catalina Basin, offshore southern California, USA, reveal a complex channel–lobe transition zone (CLTZ) and provide an opportunity to characterize an entire seafloor CLTZ in a tectonically active and confined-basin setting. The seafloor morphology, distribution of depositional and erosional features, and...
Maier, Katherine L.; Roland, Emily C.; Walton, Maureen A. L.; Conrad, James E.; Brothers, Daniel S.; Dartnell, Peter; Kluesner, Jared W. 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. Strain partitioning in southeastern Alaska: Is the Chatham Strait Fault active?
A 1200 km-long transform plate boundary passes through southeastern Alaska and northwestern British Columbia and represents one of the most seismically active, but poorly understood continental margins of North America. Although most of the plate motion is accommodated by the right-lateral Queen Charlotte–Fairweather Fault (QCFF) System,...
Brothers, Daniel; Elliott, Julie L.; Conrad, James E.; Haeussler, Peter J.; Kluesner, Jared 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 Chirp seismic-reflection data of field activity S-5-09-SC: San Pedro Basin, offshore southern California from 2009-07-06 to 2009-07-10
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2009 to explore a possible connection between the San Diego Trough Fault and the San Pedro Basin Fault. The survey is in the San Pedro Basin between Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V...
Sliter, Ray W.; Conrad, James E.; Ryan, Holly F.; Triezenberg, Peter
Expedition along a Hazardous, Fast-Moving Fault off Southeast Alaska—the Queen Charlotte-Fairweather Fault
USGS scientists hope to learn more about the earthquake hazards that this large, fast-moving fault poses to communities and tourists in Alaska and Canada.