In the background is the Research Vessel (R/V) Robert Gordon Sproul, operated by Scripps Institution of Oceanography (SIO).
Seafloor Faults off Southern California Active
More than 22 million people live along Southern California’s coast, and many more migrate there every year. Faults and earthquake threats in this region have been heavily studied on land. USGS aims to boost our knowledge about faults on the seafloor, so they can be included in hazard assessments.
Scientists did not collect highly detailed seafloor maps and seismic data beyond 25 miles off the coast of Southern California until 2008. The thinking was that faults beyond that distance would not affect U.S. coastlines, which turned out to be incorrect. Technology to map the seafloor in great detail was also very costly until the late 1990s. USGS geologist Jamie Conrad points out that even as recently as 2009, offshore fault maps of Southern California did not show that the San Diego Trough fault—one of the longest in Southern California—connects to the San Pedro fault near Santa Monica Bay. But these faults do connect. These earlier maps also showed that the Palos Verdes fault, well known because it runs partly onshore, connects with the Coronado Bank fault. But these faults do not connect. Longer faults boost the threat of larger earthquakes along this highly populated coastline, including Conrad’s childhood home in the Palos Verdes Hills.
Issue
The San Andreas fault is perhaps the best-known fault in Southern California. It’s part of a much larger system of faults generated by the Pacific and North American tectonic plates grinding past each other at a rate of about 50 millimeters a year. Other faults extending throughout Southern California also enable this boundary to move. Up to 20 percent of the movement occurs on offshore faults within 75 miles of the coast.
Some notable earthquakes in Southern California occurred on these seafloor faults. The 1933 magnitude 6.4 Long Beach earthquake on the Newport-Inglewood fault killed 115 people and caused \$40 million in damage. In 1986, the magnitude 5.4 Oceanside earthquake on an unknown segment of the San Diego Trough fault, caused at least 29 injuries, 1 death, and \$1 million in damage. And the 1951 magnitude 5.9 San Clemente Island earthquake on the San Clemente fault caused some damage in Santa Barbara and Ventura counties.
Estimating earthquake risk depends on fault characteristics, such as length; slip rate (the average distance a fault moves each year); how slip varies along segments of the fault; the average time between earthquakes; the last time the fault moved; and how it links to other active faults. These characteristics are challenging to determine for faults lying beneath a few thousand meters of seawater. Until recently, seafloor maps covering large parts of Southern California lacked adequate resolution to uncover the crucial details of fault movement and seafloor warping associated with these submerged faults.
Earthquake probability forecasts didn’t even include faults located entirely offshore until 2014, despite the potential for these faults to generate destructive earthquakes. These forecasts help organizations set earthquake insurance rates, design building codes, and prepare for disasters in California.
What the USGS is doing
The USGS began studying faults offshore Southern California in much greater detail in 1999 by collecting new seismic data: two-dimensional views that revealed faults and distorted sediment layers beneath the seafloor. Seven years later, higher resolution seismic surveys filled in missing data from key sections of some faults. Those data came from a new instrument towed just a few meters below the surface that sends out pulses of sound that penetrate the seafloor and reflect off deeper sediment and rock layers. This minisparker uses an electric spark as the sound source, and one hydrophone (underwater microphone) to record the echoes.
By emitting fan-shaped pulses of sound that bounced off the bottom, multibeam sonar could map swaths of the ocean floor in enough detail to pick up faults and the contorted environment around them. By collaborating with other agencies in 1999, the USGS used this technique to map the ocean floor off Los Angeles and San Diego in much higher resolution than ever before.
Using deep-water coring devices in 2003 and 2009, USGS scientists collected samples of seafloor sediment next to the faults to calculate the fault’s age.
In 2007, the USGS began collaborating with the Monterey Bay Aquarium Research Institute (MBARI) to survey the seafloor. Researchers used MBARI’s Autonomous Underwater Vehicle (AUV), to fly about 50 meters above the ocean bottom. This robotic submarine mapped the seafloor using multibeam sonar to reveal features as small as 1 meter. In contrast, a ship-mounted instrument operating hundreds of meters above the bottom can typically distinguish features 15 to 20 meters across. The AUV surveyed carefully selected features, such as seafloor channels displaced by faults, which provided scientists with clues to a fault’s slip rate. The AUV also carried a chirp system, which sends out a high-frequency "chirp" sound and listens with a small collection of hydrophones. It collects data beneath the seafloor, revealing layers as thin as 2 to 3 centimeters.
From 2010 to 2011, the USGS collected multibeam bathymetry, in depths of 100 to 800 meters, off the coast from Dana Point to La Jolla, one of the last areas left in Southern California to be mapped in high resolution.
What the USGS has learned
The USGS created a new offshore fault map for Southern California. The map shows an active connection between the San Pedro Basin fault and the San Diego Trough fault, previously thought to be separate faults. This continuous fault extends 260 kilometers, from offshore Santa Monica into Mexico, and is one of the longest faults in Southern California. In general, the longer a fault, the greater its earthquake potential.
Calculating a slip rate, or how much a fault moves over time, is critical when determining the fault’s earthquake hazard. Using the new high-resolution seafloor maps and seismic data, USGS scientists determined a slip rate for the first time for the San Diego Trough fault, and an underwater section of the Palos Verdes fault that differed from the onshore rates, indicating that the slip rate may change along the fault. The Palos Verdes fault runs through the top of an underwater landslide dated at 31,000 years old. Measuring how much the seafloor shifted from this clear boundary helped researchers determine the age of the fault to be 3-5 million years old.
Near the epicenter of the 1986 Oceanside earthquake, USGS scientists identified a 5-kilometer-long stepover (or short gap) in the San Diego Trough fault. Seafloor displacement along this stepover is different from regular strike-slip fault movement, which could explain some unusual characteristics of that earthquake, such as the long aftershocks that are atypical for this earthquake’s magnitude.
New seafloor data from 2008-2011 illuminate an obscure group of faults that parallel the coast about 15 to 20 kilometers from San Onofre, which may interact with the Newport-Inglewood Fault.
Detailed views of the seafloor have greatly enhanced our understanding of active faults off Southern California, and improved hazard assessments for the region. For example, this information contributed to an update of the seismic hazard assessment of the San Onofre Nuclear Generating Station in 2014, and the 2014 National Seismic Hazard Mapping Project, which included faults located entirely offshore for the first time.
Below are the current studies of the “U.S. West Coast and Alaska Marine Geohazards” Project.
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
Seafloor Faults off Southern California
Offshore Faults along Central and Northern California
Underwater Landslides off Southern California
Earthquake Hazards in Southeastern Alaska
Below are data or web applications associated with this project.
Reprocessed legacy seismic-reflection data from USGS field activity B-1-72-SC collected offshore central and southern California
Multichannel minisparker seismic-reflection and chip sub bottom data collected in the Santa Barbara Channel in July of 2018
Quaternary faults offshore of 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
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
Chirp seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
Chirp seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
Minisparker seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
Minisparker seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
Minisparker seismic-reflection data collected between Huntington Beach and San Diego, offshore of southern California, from 2008-04-28 to 2008-05-05 (USGS field activity B-1-08-SC)
Chirp seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
Minisparker seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
Below are multimedia items associated with this project.
In the background is the Research Vessel (R/V) Robert Gordon Sproul, operated by Scripps Institution of Oceanography (SIO).
Science crew from the USGS Pacific Coastal and Marine Science Center work on deployment of seismic streamer on deck of R/V Robert Gordon Sproul. Green cable is the hydrophone streamer and a "bird" is being attached to control depth in the water.
Science crew from the USGS Pacific Coastal and Marine Science Center work on deployment of seismic streamer on deck of R/V Robert Gordon Sproul. Green cable is the hydrophone streamer and a "bird" is being attached to control depth in the water.
Looking across the back deck/stern of the R/V Robert Gordon Sproul. The wire going through the block in the A-frame leads to the CHIRP sonar fish towed in the water. Oil platforms are shown in the distance.
Looking across the back deck/stern of the R/V Robert Gordon Sproul. The wire going through the block in the A-frame leads to the CHIRP sonar fish towed in the water. Oil platforms are shown in the distance.
Below are publications associated with this project.
Recency of faulting and subsurface architecture of the San Diego Bay pull-apart basin, California, USA
Morphology, structure, and kinematics of the San Clemente and Catalina faults based on high-resolution marine geophysical data, southern California Inner Continental Borderland
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, we present a suite of new high-resolution marine geo
The tectonically controlled San Gabriel Channel–Lobe Transition Zone, Catalina Basin, Southern California Borderland
The California Seafloor and Coastal Mapping Program – Providing science and geospatial data for California's State Waters
Records of continental slope sediment flow morphodynamic responses to gradient and active faulting from integrated AUV and ROV data, offshore Palos Verdes, southern California Borderland
Below are news stories associated with this project.
- Overview
More than 22 million people live along Southern California’s coast, and many more migrate there every year. Faults and earthquake threats in this region have been heavily studied on land. USGS aims to boost our knowledge about faults on the seafloor, so they can be included in hazard assessments.
Scientists did not collect highly detailed seafloor maps and seismic data beyond 25 miles off the coast of Southern California until 2008. The thinking was that faults beyond that distance would not affect U.S. coastlines, which turned out to be incorrect. Technology to map the seafloor in great detail was also very costly until the late 1990s. USGS geologist Jamie Conrad points out that even as recently as 2009, offshore fault maps of Southern California did not show that the San Diego Trough fault—one of the longest in Southern California—connects to the San Pedro fault near Santa Monica Bay. But these faults do connect. These earlier maps also showed that the Palos Verdes fault, well known because it runs partly onshore, connects with the Coronado Bank fault. But these faults do not connect. Longer faults boost the threat of larger earthquakes along this highly populated coastline, including Conrad’s childhood home in the Palos Verdes Hills.
Issue
The San Andreas fault is perhaps the best-known fault in Southern California. It’s part of a much larger system of faults generated by the Pacific and North American tectonic plates grinding past each other at a rate of about 50 millimeters a year. Other faults extending throughout Southern California also enable this boundary to move. Up to 20 percent of the movement occurs on offshore faults within 75 miles of the coast.
Some notable earthquakes in Southern California occurred on these seafloor faults. The 1933 magnitude 6.4 Long Beach earthquake on the Newport-Inglewood fault killed 115 people and caused \$40 million in damage. In 1986, the magnitude 5.4 Oceanside earthquake on an unknown segment of the San Diego Trough fault, caused at least 29 injuries, 1 death, and \$1 million in damage. And the 1951 magnitude 5.9 San Clemente Island earthquake on the San Clemente fault caused some damage in Santa Barbara and Ventura counties.
Estimating earthquake risk depends on fault characteristics, such as length; slip rate (the average distance a fault moves each year); how slip varies along segments of the fault; the average time between earthquakes; the last time the fault moved; and how it links to other active faults. These characteristics are challenging to determine for faults lying beneath a few thousand meters of seawater. Until recently, seafloor maps covering large parts of Southern California lacked adequate resolution to uncover the crucial details of fault movement and seafloor warping associated with these submerged faults.
Earthquake probability forecasts didn’t even include faults located entirely offshore until 2014, despite the potential for these faults to generate destructive earthquakes. These forecasts help organizations set earthquake insurance rates, design building codes, and prepare for disasters in California.
What the USGS is doing
The USGS began studying faults offshore Southern California in much greater detail in 1999 by collecting new seismic data: two-dimensional views that revealed faults and distorted sediment layers beneath the seafloor. Seven years later, higher resolution seismic surveys filled in missing data from key sections of some faults. Those data came from a new instrument towed just a few meters below the surface that sends out pulses of sound that penetrate the seafloor and reflect off deeper sediment and rock layers. This minisparker uses an electric spark as the sound source, and one hydrophone (underwater microphone) to record the echoes.
By emitting fan-shaped pulses of sound that bounced off the bottom, multibeam sonar could map swaths of the ocean floor in enough detail to pick up faults and the contorted environment around them. By collaborating with other agencies in 1999, the USGS used this technique to map the ocean floor off Los Angeles and San Diego in much higher resolution than ever before.
Using deep-water coring devices in 2003 and 2009, USGS scientists collected samples of seafloor sediment next to the faults to calculate the fault’s age.
In 2007, the USGS began collaborating with the Monterey Bay Aquarium Research Institute (MBARI) to survey the seafloor. Researchers used MBARI’s Autonomous Underwater Vehicle (AUV), to fly about 50 meters above the ocean bottom. This robotic submarine mapped the seafloor using multibeam sonar to reveal features as small as 1 meter. In contrast, a ship-mounted instrument operating hundreds of meters above the bottom can typically distinguish features 15 to 20 meters across. The AUV surveyed carefully selected features, such as seafloor channels displaced by faults, which provided scientists with clues to a fault’s slip rate. The AUV also carried a chirp system, which sends out a high-frequency "chirp" sound and listens with a small collection of hydrophones. It collects data beneath the seafloor, revealing layers as thin as 2 to 3 centimeters.
From 2010 to 2011, the USGS collected multibeam bathymetry, in depths of 100 to 800 meters, off the coast from Dana Point to La Jolla, one of the last areas left in Southern California to be mapped in high resolution.
What the USGS has learned
The USGS created a new offshore fault map for Southern California. The map shows an active connection between the San Pedro Basin fault and the San Diego Trough fault, previously thought to be separate faults. This continuous fault extends 260 kilometers, from offshore Santa Monica into Mexico, and is one of the longest faults in Southern California. In general, the longer a fault, the greater its earthquake potential.
Calculating a slip rate, or how much a fault moves over time, is critical when determining the fault’s earthquake hazard. Using the new high-resolution seafloor maps and seismic data, USGS scientists determined a slip rate for the first time for the San Diego Trough fault, and an underwater section of the Palos Verdes fault that differed from the onshore rates, indicating that the slip rate may change along the fault. The Palos Verdes fault runs through the top of an underwater landslide dated at 31,000 years old. Measuring how much the seafloor shifted from this clear boundary helped researchers determine the age of the fault to be 3-5 million years old.
Near the epicenter of the 1986 Oceanside earthquake, USGS scientists identified a 5-kilometer-long stepover (or short gap) in the San Diego Trough fault. Seafloor displacement along this stepover is different from regular strike-slip fault movement, which could explain some unusual characteristics of that earthquake, such as the long aftershocks that are atypical for this earthquake’s magnitude.
New seafloor data from 2008-2011 illuminate an obscure group of faults that parallel the coast about 15 to 20 kilometers from San Onofre, which may interact with the Newport-Inglewood Fault.
Detailed views of the seafloor have greatly enhanced our understanding of active faults off Southern California, and improved hazard assessments for the region. For example, this information contributed to an update of the seismic hazard assessment of the San Onofre Nuclear Generating Station in 2014, and the 2014 National Seismic Hazard Mapping Project, which included faults located entirely offshore for the first time.
- Science
Below are the current studies of the “U.S. West Coast and Alaska Marine Geohazards” Project.
Coastal and Marine Geohazards of the U.S. West Coast and Alaska
Coastal and marine geohazards are sudden and extreme events beneath the ocean that threaten coastal populations. Such underwater hazards include earthquakes, volcanic eruptions, landslides, and tsunamis.ByNatural Hazards Mission Area, Coastal and Marine Hazards and Resources Program, Pacific Coastal and Marine Science Center, 3-D CT Core Imaging Laboratory, Core Preparation and Analysis Laboratory and Sample Repositories, Big Sur Landslides, Deep Sea Exploration, Mapping and Characterization, Subduction Zone ScienceSeafloor Faults off Southern California
More than 22 million people live along Southern California’s coast, and many more migrate there every year. Faults and earthquake threats in this region have been heavily studied on land. USGS aims to boost our knowledge about faults on the seafloor, so they can be included in hazard assessments.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.Underwater Landslides off Southern California
An earthquake can trigger a landslide along the ocean floor, which can then set off a tsunami. Without modern, high-resolution imaging of the seafloor, many historical slides and threats from future slides remain undetected.Earthquake Hazards in Southeastern Alaska
Over the last 100 years, the Queen Charlotte-Fairweather fault system has produced large-magnitude earthquakes affecting both Canada and the U.S. To fill in missing details about its offshore location and structure, USGS uses sophisticated techniques to truly understand the fault’s hazard potential. - Data
Below are data or web applications associated with this project.
Reprocessed legacy seismic-reflection data from USGS field activity B-1-72-SC collected offshore central and southern California
Seismic-reflection data were collected offshore central and southern California in 1972 aboard the USNS Bartlett (USGS Field Activity B-1-72-SC). In 2021 these legacy data were reprocessed to improve accuracy and geologic resolvability of Californias continental margin. The effort to rescue and reprocess these legacy seismic-reflection data profiles was supported by Pacific Gas and Electric (PG&E)Multichannel minisparker seismic-reflection and chip sub bottom data collected in the Santa Barbara Channel in July of 2018
High-resolution multichannel minisparker seismic-reflection and chirp sub-bottom data were collected by the U.S. Geological Survey in July of 2018 between Point Conception and Coal Oil Point in the Santa Barbara Channel, California. Data were collected aboard the USGS R/V Parke Snavely during field activity 2018-645-FA. Data were acquired to support the USGS geologic hazards projects to aide hazarQuaternary 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 and matching KML file have been compiled from previously published mapping where relatively dense, high-resolution marine geophysical daMultichannel 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 that were collected in February of 2016 from the Catalina Basin offshore southern California by the U.S. Geological Survey Pacific and Coastal Marine Science Center in cooperation with the University of Washington. Data were collected aboard the University of Washington's R/V TMultibeam 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 the U.S. Geological Survey, Pacific Coastal and Marine Science Center (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 Kongsberg EM300 multibeam echosoundeChirp seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
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 the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 subbottom profiler. SubbottoChirp seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2010 to collect information on active offshore faults. The survey is area is offshore southern California between Oceanside and La Jolla. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using an EdgeTech 512 chirp subbottom profiler. SMinisparker seismic-reflection data collected offshore of San Diego and Los Angeles Counties, southern California, from 2011-06-08 to 2011-06-22 (USGS field activity S-7-11-SC)
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 the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker and an Edgetech 512Minisparker seismic-reflection data collected between Oceanside and La Jolla, offshore of southern California, from 2010-06-01 to 2010-06-12 (USGS field activity S-12-10-SC)
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 the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic pMinisparker seismic-reflection data collected between Huntington Beach and San Diego, offshore of southern California, from 2008-04-28 to 2008-05-05 (USGS field activity B-1-08-SC)
This dataset includes raw and processed, high-resolution seismic-reflection data collected in 2008 to collect information on active offshore faults. The survey area is offshore southern California between Huntington Beach and San Diego. The data were collected aboard the R/V Bold. The seismic-reflection data were acquired using a SIG 2mille minisparker. Subbottom acoustic penetration spanned tensChirp seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
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 Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data werMinisparker seismic-reflection data collected in the San Pedro Basin, offshore of southern California, from 2009-07-06 to 2009-07-10 (USGS field activity S-5-09-SC)
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 Santa Catalina Island and San Pedro, California. The data were collected aboard the U.S. Geological Survey R/V Parke Snavely. The seismic-reflection data wer - Multimedia
Below are multimedia items associated with this project.
Seismic science crew and the R/V SproulIn the background is the Research Vessel (R/V) Robert Gordon Sproul, operated by Scripps Institution of Oceanography (SIO).
In the background is the Research Vessel (R/V) Robert Gordon Sproul, operated by Scripps Institution of Oceanography (SIO).
Deploying seismic streamerScience crew from the USGS Pacific Coastal and Marine Science Center work on deployment of seismic streamer on deck of R/V Robert Gordon Sproul. Green cable is the hydrophone streamer and a "bird" is being attached to control depth in the water.
Science crew from the USGS Pacific Coastal and Marine Science Center work on deployment of seismic streamer on deck of R/V Robert Gordon Sproul. Green cable is the hydrophone streamer and a "bird" is being attached to control depth in the water.
Sunset on the R/V SproulLooking across the back deck/stern of the R/V Robert Gordon Sproul. The wire going through the block in the A-frame leads to the CHIRP sonar fish towed in the water. Oil platforms are shown in the distance.
Looking across the back deck/stern of the R/V Robert Gordon Sproul. The wire going through the block in the A-frame leads to the CHIRP sonar fish towed in the water. Oil platforms are shown in the distance.
- Publications
Below are publications associated with this project.
Recency of faulting and subsurface architecture of the San Diego Bay pull-apart basin, California, USA
In southern California, plate boundary motion between the North American and Pacific plates is distributed across several sub-parallel fault systems. The offshore faults of the California Continental Borderland (CCB) are thought to accommodate ~10-15% of the total plate boundary motion, but the exact distribution of slip and the mechanics of slip partitioning remain uncertain. The Newport-InglewooAuthorsDrake Moore Singleton, Jillian M. Maloney, Daniel S. Brothers, Shannon Klotsko, Neal W. Driscoll, Thomas K. RockwellMorphology, 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 Clemente fault (SCF) may be accommodating up to halAuthorsMaureen A. L. Walton, Daniel S. Brothers, James E. Conrad, Katherine L. Maier, Emily C. Roland, Jared W. Kluesner, Peter DartnellThe 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, we present a suite of new high-resolution marine geo
AuthorsDaniel S. Brothers, Katherine L. Maier, Jared W. Kluesner, James E. Conrad, Jason ChaytorThe 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 location of depocenters in the CLTZ are controlledAuthorsKatherine L. Maier, Emily C. Roland, Maureen A. L. Walton, James E. Conrad, Daniel S. Brothers, Peter Dartnell, Jared W. KluesnerThe 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 high-resolution bathymetric mapping, largely to suppoAuthorsSamuel Y. Johnson, Guy R. Cochrane, Nadine E. Golden, Peter Dartnell, Stephen Hartwell, Susan A. Cochran, Janet WattRecords of continental slope sediment flow morphodynamic responses to gradient and active faulting from integrated AUV and ROV data, offshore Palos Verdes, southern California Borderland
Variations in seabed gradient are widely acknowledged to influence deep-water deposition, but are often difficult to measure in sufficient detail from both modern and ancient examples. On the continental slope offshore Los Angeles, California, autonomous underwater vehicle, remotely operated vehicle, and shipboard methods were used to collect a dense grid of high-resolution multibeam bathymetry, cAuthorsKatherine L. Maier, Daniel S. Brothers, Charles K. Paull, Mary McGann, David W. Caress, James E. Conrad - News
Below are news stories associated with this project.