Geophysicist Emeritus with the USGS Pacific Coastal and Marine Science Center
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.
U.S. Geological Survey Gas Hydrates Project
The USGS Gas Hydrates Project has been making contributions to advance understanding of US and international gas hydrates science for at least three decades. The research group working on gas hydrates at the USGS is among the largest in the US and has expertise in all the major geoscience disciplines, as well as in the physics and chemistry of gas hydrates, the geotechnical properties of hydrate...
Filter Total Items: 13
Multichannel sparker and chirp seismic reflection data collected offshore South East Alaska during USGS Field Activity 2017-621-FA
High-resolution multichannel seismic reflection data and chirp sub-bottom data were collected by the U.S. Geological Survey in July and August 2017 offshore southeast Alaska to expand data coverage along the Queen Charlotte Fault system. Data were acquired to study earthquake hazards, fault mechanics and submarine mass wasting processes along the Queen Charlotte fault system, a 1200 km long transf
Calibrated marine sparker source amplitude decay versus offset offshore Santa Cruz, California
This two-vessel survey was designed to quantify the decay of sound emitted from the SIG ELP790 minisparker (powered at 700 joules) and from the Applied Acoustics Delta Sparker (powered at 1.0 and 2.4 kilojoules) as a function of distance during marine geophysical surveys. Seven transect sites were surveyed at five different water depths (25, 50, 100, 200, and 600 meters) to compare the effects of
Gridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
This data release provides bathymetry data for the western part of Passage Canal, near Whittier Alaska. It was collected by the USGS Pacific Coastal and Marine Science Center in 2011 under Field Activity Number A0111GA. The data release consists of a 5 m grid, derived from processed and cleaned multibeam data. Depths were corrected for tidal variations and calculated using conductivity, temperatur
High-resolution multi-channel and Chirp seismic-reflection data from USGS cruise 2018-641-FA collected in south-central California in support of the Bureau of Ocean Energy Management Cal DIG I offshore alternative energy project
This dataset is one of several collected as part of the Bureau of Ocean Energy Management (BOEM)-funded California Deepwater Investigations and Groundtruthing (Cal DIG I) project. The purpose of the study is to assess shallow geohazards, benthic habitats, and thereby the potential for alternative energy infrastructure (namely floating wind turbines) offshore south-central California due to its pro
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. Sub-bottom acoustic pe
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 the 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.
Chirp, multichannel minisparker, and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013
Multichannel minisparker and boomer seismic-reflection and chirp sub bottom data were collected by the U.S. Geological Survey in September of 2013 in Port Valdez, Alaska. Data were collected aboard the USGS R/V Alaskan Gyre during field activity G-01-13-GA. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location. High-resolution multichannel seismic-reflection
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 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 T
Chirp and minisparker seismic-reflection data of field activity L-1-06-SF collected offshore Golden Gate, San Francisco County, California from 2006-09-25 to 2006-10-03
High-resolution single-channel Chirp and minisparker seismic-reflection data were collected by the U.S. Geological Survey in September and October 2006, offshore Bolinas to San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Chirp data were collected using an EdgeTech 512 chirp subbottom system and were recorded with a Triton SB-Logger. Minisparke
Minimal offshore extent of ice-bearing (subsea) permafrost on the U.S. Beaufort Sea margin
The present-day distribution of subsea permafrost beneath high-latitude continental shelves has implications for sea level rise and climate change since the Last Glacial Maximum (~20,000 years ago). Because permafrost can be spatially associated with gas hydrate (which may be thermodynamically stable within the several hundred meters above and below the base of permafrost), the contemporary distri
Multichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06
This data release contains approximately 190 line-kilometers of processed, high-resolution multichannel seismic-reflection (MCS) profiles that were collected aboard the R/V Snavely in 2015 on U.S. Geological Survey cruise 2015-617-FA in Monterey Bay, offshore central California. The majority of MCS profiles collected are oriented north-south across the Monterey Canyon head to address marine geohaz
Multibeam and multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA
Multibeam bathymetry and multisparker data were collected along the Queen Charlotte-Fairweather Fault between Icy Point and Dixon Entrance, offshore southeastern Alaska from 2016-05-17 to 2016-06-12.
California State Waters Map Series: offshore of Refugio Beach, California
In 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 California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar
California State Waters Map Series: Offshore of Refugio Beach, California
In 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 California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonar
California State Waters Map Series: offshore of Coal Oil Point, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: Offshore of Coal Oil Point, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: Offshore of Santa Barbara, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: offshore of Santa Barbara, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: Offshore of Carpinteria, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series: offshore of Carpinteria, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series--Offshore of Ventura, California
In 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 seafloor maps through collection, integration, interpretation, and
California State Waters Map Series — Offshore of Ventura, California
In 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 seafloor maps through collection, integration, interpretation, and
Filter Total Items: 37
Categorizing active marine acoustic sources based on their potential to affect marine animals
Marine acoustic sources are widely used for geophysical imaging, oceanographic sensing, and communicating with and tracking objects or robotic vehicles in the water column. Under the U.S. Marine Mammal Protection Act and similar regulations in several other countries, the impact of controlled acoustic sources is assessed based on whether the sound levels received by marine mammals meet the criteri
Gas hydrates on Alaskan marine margins
Gas hydrate distributions on the marine margins of the U.S. state of Alaska are more poorly known than those on other U.S. margins, where bottom simulating reflections have been systematically mapped on marine seismic data to support modern, quantitative assessments of gas-in-place in gas hydrates. The extent of bottom simulating reflections in the U.S. Beaufort Sea has been known since the late 1
Submarine landslide kinematics derived from high-resolution imaging in Port Valdez, Alaska
Submarine landslides caused by strong ground shaking during the M9.2 1964 Great Alaska earthquake generated a tsunami that destroyed much of the old town of Valdez, Alaska, and was responsible for 32 deaths at that location. We explore structural details of the 1964 landslide deposit, as well as landslide deposits from earlier events, in order to characterize kinematics of the landslide process. W
Measurement of sounds emitted by certain high-resolution geophysical survey systems
Scientific questions regarding the impact of anthropomorphic noise in the marine environment have resulted in an increasing number of regulatory requirements and precautionary mitigation strategies to reduce the risks associated with high-resolution marine geophysical surveys performed in waters subjected to government jurisdiction. An example of regulatory frameworks includes the Marine Mammal Pr
Practical approaches to maximizing the resolution of sparker seismic reflection data
Sparkers are a type of sound source widely used by the marine seismic community to provide high-resolution imagery of the shallow sub-bottom (i.e.,
Controls on submarine canyon head evolution: Monterey Canyon, offshore central California
The Monterey submarine canyon, incised across the continental shelf in Monterey Bay, California, provides a record of the link between onshore tectonism, fluvial transport, and deep-marine deposition. High-resolution seismic-reflection imaging in Monterey Bay reveals an extensive paleocanyon unit buried below the seafloor of the continental shelf around Monterey and Soquel canyon heads. Paleocanyo
Gas hydrate quantification using full-waveform inversion of sparse ocean-bottom seismic data: A case study from Green Canyon Block 955, Gulf of Mexico
We present a case study of gas hydrate quantification using dense short-offset multichannel seismic (MCS) and sparse long-offset ocean-bottom-seismometer (OBS) data in lease block Green Canyon 955 (GC955), Gulf of Mexico (GOM), where the presence of gas hydrate was interpreted using logging while drilling (LWD) data acquired by the GOM Gas Hydrate Joint Industry Project Leg II expedition. We use f
High-resolution seismic characterization of the gas and gas hydrate system at Green Canyon 955, Gulf of Mexico, USA
The Pliocene and Pleistocene sediments at lease block Green Canyon 955 (GC955) in the Gulf of Mexico include sand-rich strata with high saturations of gas hydrate; these gas hydrate accumulations and the associated geology have been characterized over the past decade using conventional industry three-dimensional (3D) seismic data and dedicated logging-while-drilling (LWD) borehole data. To improve
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 Hayward fault as it traverses San Pablo Bay and ben
Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 2. Borehole constraints
Borehole logging data from legacy wells directly constrain the contemporary distribution of subsea permafrost in the sedimentary section at discrete locations on the U.S. Beaufort Margin and complement recent regional analyses of exploration seismic data to delineate the permafrost's offshore extent. Most usable borehole data were acquired on a ∼500 km stretch of the margin and within 30 km of the
Subsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data
Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U.
Science and Products
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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.U.S. Geological Survey Gas Hydrates Project
The USGS Gas Hydrates Project has been making contributions to advance understanding of US and international gas hydrates science for at least three decades. The research group working on gas hydrates at the USGS is among the largest in the US and has expertise in all the major geoscience disciplines, as well as in the physics and chemistry of gas hydrates, the geotechnical properties of hydrate... - Data
Filter Total Items: 13
Multichannel sparker and chirp seismic reflection data collected offshore South East Alaska during USGS Field Activity 2017-621-FA
High-resolution multichannel seismic reflection data and chirp sub-bottom data were collected by the U.S. Geological Survey in July and August 2017 offshore southeast Alaska to expand data coverage along the Queen Charlotte Fault system. Data were acquired to study earthquake hazards, fault mechanics and submarine mass wasting processes along the Queen Charlotte fault system, a 1200 km long transfCalibrated marine sparker source amplitude decay versus offset offshore Santa Cruz, California
This two-vessel survey was designed to quantify the decay of sound emitted from the SIG ELP790 minisparker (powered at 700 joules) and from the Applied Acoustics Delta Sparker (powered at 1.0 and 2.4 kilojoules) as a function of distance during marine geophysical surveys. Seven transect sites were surveyed at five different water depths (25, 50, 100, 200, and 600 meters) to compare the effects ofGridded Data from a 2011 Multibeam Bathymetric Survey of the Western Part of Passage Canal, Near Whittier, Alaska
This data release provides bathymetry data for the western part of Passage Canal, near Whittier Alaska. It was collected by the USGS Pacific Coastal and Marine Science Center in 2011 under Field Activity Number A0111GA. The data release consists of a 5 m grid, derived from processed and cleaned multibeam data. Depths were corrected for tidal variations and calculated using conductivity, temperaturHigh-resolution multi-channel and Chirp seismic-reflection data from USGS cruise 2018-641-FA collected in south-central California in support of the Bureau of Ocean Energy Management Cal DIG I offshore alternative energy project
This dataset is one of several collected as part of the Bureau of Ocean Energy Management (BOEM)-funded California Deepwater Investigations and Groundtruthing (Cal DIG I) project. The purpose of the study is to assess shallow geohazards, benthic habitats, and thereby the potential for alternative energy infrastructure (namely floating wind turbines) offshore south-central California due to its proMultichannel 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. Sub-bottom acoustic peChirp 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 the 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.Chirp, multichannel minisparker, and boomer seismic-reflection data from USGS field activity G-01-13-GA collected in Port Valdez, Alaska, in September 2013
Multichannel minisparker and boomer seismic-reflection and chirp sub bottom data were collected by the U.S. Geological Survey in September of 2013 in Port Valdez, Alaska. Data were collected aboard the USGS R/V Alaskan Gyre during field activity G-01-13-GA. Sub-bottom acoustic penetration spans several hundreds of meters and is variable by location. High-resolution multichannel seismic-reflectionMultichannel 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 TChirp and minisparker seismic-reflection data of field activity L-1-06-SF collected offshore Golden Gate, San Francisco County, California from 2006-09-25 to 2006-10-03
High-resolution single-channel Chirp and minisparker seismic-reflection data were collected by the U.S. Geological Survey in September and October 2006, offshore Bolinas to San Francisco, California. Data were collected aboard the R/V Lakota, during field activity L-1-06-SF. Chirp data were collected using an EdgeTech 512 chirp subbottom system and were recorded with a Triton SB-Logger. MinisparkeMinimal offshore extent of ice-bearing (subsea) permafrost on the U.S. Beaufort Sea margin
The present-day distribution of subsea permafrost beneath high-latitude continental shelves has implications for sea level rise and climate change since the Last Glacial Maximum (~20,000 years ago). Because permafrost can be spatially associated with gas hydrate (which may be thermodynamically stable within the several hundred meters above and below the base of permafrost), the contemporary distriMultichannel minisparker seismic-reflection data of field activity 2015-617-FA; Monterey Bay, offshore central California from 2015-02-23 to 2015-03-06
This data release contains approximately 190 line-kilometers of processed, high-resolution multichannel seismic-reflection (MCS) profiles that were collected aboard the R/V Snavely in 2015 on U.S. Geological Survey cruise 2015-617-FA in Monterey Bay, offshore central California. The majority of MCS profiles collected are oriented north-south across the Monterey Canyon head to address marine geohazMultibeam and multichannel sparker seismic-reflection data between Cross Sound and Dixon Entrance, offshore southeastern Alaska, collected from 2016-05-17 to 2016-06-12 during field activity 2016-625-FA
Multibeam bathymetry and multisparker data were collected along the Queen Charlotte-Fairweather Fault between Icy Point and Dixon Entrance, offshore southeastern Alaska from 2016-05-17 to 2016-06-12. - Maps
California State Waters Map Series: offshore of Refugio Beach, California
In 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 California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonarCalifornia State Waters Map Series: Offshore of Refugio Beach, California
In 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 California’s State Waters. The CSMP approach is to create highly detailed seafloor maps through collection, integration, interpretation, and visualization of swath sonarCalifornia State Waters Map Series: offshore of Coal Oil Point, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series: Offshore of Coal Oil Point, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series: Offshore of Santa Barbara, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series: offshore of Santa Barbara, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series: Offshore of Carpinteria, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series: offshore of Carpinteria, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series--Offshore of Ventura, California
In 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 seafloor maps through collection, integration, interpretation, andCalifornia State Waters Map Series — Offshore of Ventura, California
In 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 seafloor maps through collection, integration, interpretation, and - Multimedia
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Filter Total Items: 37
Categorizing active marine acoustic sources based on their potential to affect marine animals
Marine acoustic sources are widely used for geophysical imaging, oceanographic sensing, and communicating with and tracking objects or robotic vehicles in the water column. Under the U.S. Marine Mammal Protection Act and similar regulations in several other countries, the impact of controlled acoustic sources is assessed based on whether the sound levels received by marine mammals meet the criteriGas hydrates on Alaskan marine margins
Gas hydrate distributions on the marine margins of the U.S. state of Alaska are more poorly known than those on other U.S. margins, where bottom simulating reflections have been systematically mapped on marine seismic data to support modern, quantitative assessments of gas-in-place in gas hydrates. The extent of bottom simulating reflections in the U.S. Beaufort Sea has been known since the late 1Submarine landslide kinematics derived from high-resolution imaging in Port Valdez, Alaska
Submarine landslides caused by strong ground shaking during the M9.2 1964 Great Alaska earthquake generated a tsunami that destroyed much of the old town of Valdez, Alaska, and was responsible for 32 deaths at that location. We explore structural details of the 1964 landslide deposit, as well as landslide deposits from earlier events, in order to characterize kinematics of the landslide process. WMeasurement of sounds emitted by certain high-resolution geophysical survey systems
Scientific questions regarding the impact of anthropomorphic noise in the marine environment have resulted in an increasing number of regulatory requirements and precautionary mitigation strategies to reduce the risks associated with high-resolution marine geophysical surveys performed in waters subjected to government jurisdiction. An example of regulatory frameworks includes the Marine Mammal PrPractical approaches to maximizing the resolution of sparker seismic reflection data
Sparkers are a type of sound source widely used by the marine seismic community to provide high-resolution imagery of the shallow sub-bottom (i.e.,Controls on submarine canyon head evolution: Monterey Canyon, offshore central California
The Monterey submarine canyon, incised across the continental shelf in Monterey Bay, California, provides a record of the link between onshore tectonism, fluvial transport, and deep-marine deposition. High-resolution seismic-reflection imaging in Monterey Bay reveals an extensive paleocanyon unit buried below the seafloor of the continental shelf around Monterey and Soquel canyon heads. PaleocanyoGas hydrate quantification using full-waveform inversion of sparse ocean-bottom seismic data: A case study from Green Canyon Block 955, Gulf of Mexico
We present a case study of gas hydrate quantification using dense short-offset multichannel seismic (MCS) and sparse long-offset ocean-bottom-seismometer (OBS) data in lease block Green Canyon 955 (GC955), Gulf of Mexico (GOM), where the presence of gas hydrate was interpreted using logging while drilling (LWD) data acquired by the GOM Gas Hydrate Joint Industry Project Leg II expedition. We use fHigh-resolution seismic characterization of the gas and gas hydrate system at Green Canyon 955, Gulf of Mexico, USA
The Pliocene and Pleistocene sediments at lease block Green Canyon 955 (GC955) in the Gulf of Mexico include sand-rich strata with high saturations of gas hydrate; these gas hydrate accumulations and the associated geology have been characterized over the past decade using conventional industry three-dimensional (3D) seismic data and dedicated logging-while-drilling (LWD) borehole data. To improveMissing 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 Hayward fault as it traverses San Pablo Bay and benSubsea ice-bearing permafrost on the U.S. Beaufort Margin: 2. Borehole constraints
Borehole logging data from legacy wells directly constrain the contemporary distribution of subsea permafrost in the sedimentary section at discrete locations on the U.S. Beaufort Margin and complement recent regional analyses of exploration seismic data to delineate the permafrost's offshore extent. Most usable borehole data were acquired on a ∼500 km stretch of the margin and within 30 km of theSubsea ice-bearing permafrost on the U.S. Beaufort Margin: 1. Minimum seaward extent defined from multichannel seismic reflection data
Subsea ice-bearing permafrost (IBPF) and associated gas hydrate in the Arctic have been subject to a warming climate and saline intrusion since the last transgression at the end of the Pleistocene. The consequent degradation of IBPF is potentially associated with significant degassing of dissociating gas hydrate deposits. Previous studies interpreted the distribution of subsea permafrost on the U. - News