Permeability and pressure measurements in Lesser Antilles submarine slides; evidence for pressure-driven slow-slip failure

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doi: 10.1002/2015JB012061
Author(s): Hornbach, Matthew J.; Manga, Michael; Genecov, Michael; Valdez, Robert; Miller, Peter; Saffer, Demian; Adelstein, Esther; Lafuerza, Sara; Adachi, Tatsuya; Breitkreuz, Christoph; Jutzeler, Martin; Le Friant, Anne; Ishizuka, Osamu; Morgan, Sally; Slagle, Angela; Talling, Peter J.; Fraass, Andrew; Watt, Sebastian F. L.; Stroncik, Nicole A.; Aljahdali, Mohammed; Boudon, Georges; Fujinawa, Akihiko; Hatfield, Robert; Kataoka, Kyoko; Maeno, Fukashi; Martinez-Colon, Michael; McCanta, Molly; Palmer, Martin; Stinton, Adam; Subramanyam, K. S. V.; Tamura, Yoshihiko; Villemant, Benoît; Wall-Palmer, Deborah; Wang, Fei
Author Affiliation(s): Primary:
Southern Methodist University, Department of Earth Sciences, Dallas, TX, United States
University of California at Berkeley, United States
Pennsylvania State University, United States
Université Pierre et Marie Curie, France
Yamagata University, Japan
Technische Universität Bergakademie Freiberg, Germany
National Oceanography Centre, United Kingdom
Institut de Physique du Globe de Paris, France
Geological Survey of Japan, Japan
University of Leicester, United Kingdom
Lamont-Doherty Earth Observatory, United States
University of Massachusetts at Amherst, United States
University of Birmingham, United Kingdom
Texas A&M University, United States
Florida State University, United States
Ibaraki University, Japan
Oregon State University, United States
Niigata University, Japan
University of Tokyo, Japan
University of South Florida, United States
Tufts University, United States
University of Southampton, United Kingdom
University of the West Indies, Trinidad and Tobago
National Geophysical Research Institute, India
Japan Agency for Marine-Earth Science and Technology, Japan
Plymouth University, United Kingdom
Chinese Academy of Sciences, Institute of Geology and Geophysics, China
Volume Title: Journal of Geophysical Research: Solid Earth
Source: Journal of Geophysical Research: Solid Earth, 120(12), p.7986-8011. Publisher: Wiley-Blackwell for American Geophysical Union, Washington, DC, United States. ISSN: 2169-9313
Note: In English. 130 refs.; illus., incl. 3 tables, sects.
Summary: Recent studies hypothesize that some submarine slides fail via pressure-driven slow-slip deformation. To test this hypothesis, this study derives pore pressures in failed and adjacent unfailed deep marine sediments by integrating rock physics models, physical property measurements on recovered sediment core, and wireline logs. Two drill sites (U1394 and U1399) drilled through interpreted slide debris; a third (U1395) drilled into normal marine sediment. Near-hydrostatic fluid pressure exists in sediments at site U1395. In contrast, results at both sites U1394 and U1399 indicate elevated pore fluid pressures in some sediment. We suggest that high pore pressure at the base of a submarine slide deposit at site U1394 results from slide shearing. High pore pressure exists throughout much of site U1399, and Mohr circle analysis suggests that only slight changes in the stress regime will trigger motion. Consolidation tests and permeability measurements indicate moderately low (∼10-16-10-17 m2) permeability and overconsolidation in fine-grained slide debris, implying that these sediments act as seals. Three mechanisms, in isolation or in combination, may produce the observed elevated pore fluid pressures at site U1399: (1) rapid sedimentation, (2) lateral fluid flow, and (3) shearing that causes sediments to contract, increasing pore pressure. Our preferred hypothesis is this third mechanism because it explains both elevated fluid pressure and sediment overconsolidation without requiring high sedimentation rates. Our combined analysis of subsurface pore pressures, drilling data, and regional seismic images indicates that slope failure offshore Martinique is perhaps an ongoing, creep-like process where small stress changes trigger motion. Abstract Copyright (2015), . The Authors.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Antilles; Atlantic Ocean; Caribbean Sea; Caribbean region; Deformation; Dynamics; Expedition 340; Failures; Hydrostatic pressure; IODP Site U1394; IODP Site U1395; IODP Site U1399; Integrated Ocean Drilling Program; Lesser Antilles; Marine sediments; Mass movements; Measurement; North Atlantic; Permeability; Pore pressure; Pressure; Sedimentation; Sedimentation rates; Sediments; Slumping; West Indies
Coordinates: N141640 N164315 W0612450 W0622710
Record ID: 2016084652
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom