Patrick Hart
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...
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., < 1000 m). Although sparkers are relatively simple, inexpensive, and high-frequency (100–2500 Hz) sources, they have several potential pitfalls due to their complicated and...
Kluesner, Jared; Brothers, Daniel; Hart, Patrick E.; Miller, Nathaniel C.; Hatcher, Gerry 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...
Maier, Katherine L.; Johnson, Samuel Y.; Hart, Patrick E. 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...
Wang, Jiliang; Jaiswal, Priyank; Haines, Seth S.; Hart, Patrick E.; Wu, Shiguo 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...
Haines, Seth S.; Hart, Patrick E.; Collett, Timothy S.; Shedd, William; Frye, Matthew; Weimer, Paul; Boswell, Ray 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. 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...
Brothers, Laura L.; Herman, Bruce M.; Hart, Patrick E.; Ruppel, Carolyn D. 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 ∼...
Ruppel, Carolyn D.; Herman, Bruce M.; Brothers, Laura L.; Hart, Patrick E.
Processing of multichannel seismic reflection data acquired in 2013 for seismic investigations of gas hydrates in the Gulf of Mexico
As part of a cooperative effort among the U.S. Geological Survey (USGS), the U.S. Department of Energy, and the U.S. Department of the Interior Bureau of Ocean Energy Management, two grids of two-dimensional multichannel seismic reflection data were acquired in the Gulf of Mexico over lease blocks Green Canyon 955 and Walker Ridge 313 between...
Miller, John J.; Agena, Warren F.; Haines, Seth S.; Hart, Patrick E.
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,...
Johnson, Samuel Y.; Cochran, Susan A.; Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Krigsman, Lisa M.; Dieter, Bryan E.; Conrad, James E.; Greene, H. Gary; Seitz, Gordon G.; Endris, Charles A.; Sliter, Ray W.; Wong, Florence L.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Yoklavich, Mary M.; East, Amy E.; Hart, Patrick E. Widespread gas hydrate instability on the upper U.S. Beaufort margin
The most climate-sensitive methane hydrate deposits occur on upper continental slopes at depths close to the minimum pressure and maximum temperature for gas hydrate stability. At these water depths, small perturbations in intermediate ocean water temperatures can lead to gas hydrate dissociation. The Arctic Ocean has experienced more dramatic...
Phrampus, Benjamin J.; Hornbach, Matthew J.; Ruppel, Carolyn D.; Hart, Patrick E.
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...
Johnson, Samuel Y.; Cochran, Susan A.; Johnson, Samuel Y.; Dartnell, Peter; Cochrane, Guy R.; Golden, Nadine E.; Phillips, Eleyne L.; Ritchie, Andrew C.; Kvitek, Rikk G.; Dieter, Bryan E.; Conrad, James E.; Lorenson, T.D.; Krigsman, Lisa M.; Greene, H. Gary; Endris, Charles A.; Seitz, Gordon G.; Finlayson, David P.; Sliter, Ray W.; Wong, Florence L.; Erdey, Mercedes D.; Gutierrez, Carlos I.; Leifer, Ira; Yoklavich, Mary M.; Draut, Amy E.; Hart, Patrick E.; Hostettler, Frances D.; Peters, Kenneth E.; Kvenvolden, Keith A.; Rosenbauer, Robert J.; Fong, Grace
Cruise report for P1-13-LA, U.S. Geological Survey gas hydrates research cruise, R/V Pelican April 18 to May 3, 2013, deepwater Gulf of Mexico
The U.S. Geological Survey led a seismic acquisition cruise in the Gulf of Mexico from April 18 to May 3, 2013, with the objectives of (1) achieving improved imaging and characterization at two established gas hydrate study sites, and (2) refining geophysical methods for gas hydrate characterization in other locations. We conducted this...
Haines, Seth S.; Hart, Patrick E.; Ruppel, Carolyn; O'Brien, Thomas; Baldwin, Wayne; White, Jenny; Moore, Eric; Dal Ferro, Peter; Lemmond, Peter
Subsea Permafrost and Associated Methane Hydrate on the U.S. Arctic Ocean Margin
A new publication by USGS and BOEM provides the most complete information to date about the seaward extent of remaining subsea permafrost and possible relict gas hydrate beneath the U.S. Beaufort Sea margin at the edge of the Arctic Ocean.