Massive methane release triggered by seafloor erosion offshore southwestern Japan

Research Article| November 01, 2010 Massive methane release triggered by seafloor erosion offshore southwestern Japan N.L. Bangs; N.L. Bangs * 1University of Texas Institute for Geophysics, J.J. Pickle Research Campus, Building 196, 10100 Burnet Road, Austin, Texas 78758-4445, USA *E-mail: nathan@ig.utexas.edu. Search for other works by this author on: GSW Google Scholar M.J. Hornbach; M.J. Hornbach 1University of Texas Institute for Geophysics, J.J. Pickle Research Campus, Building 196, 10100 Burnet Road, Austin, Texas 78758-4445, USA Search for other works by this author on: GSW Google Scholar G.F. Moore; G.F. Moore 2Department of Geology and Geophysics, University of Hawaii, Honolulu, Hawaii 96822, USA3Institute for Frontier Research on Earth Evolution, Japan Marine Science and Technology Center, 3173-25 Showa-machi, Yokohama 236-0001, Japan Search for other works by this author on: GSW Google Scholar J.-O. Park J.-O. Park 3Institute for Frontier Research on Earth Evolution, Japan Marine Science and Technology Center, 3173-25 Showa-machi, Yokohama 236-0001, Japan4Ocean Research Institute, University of Tokyo, 1-15-1 Minamidai, Nakano-ku, Tokyo 164-8639, Japan Search for other works by this author on: GSW Google Scholar Geology (2010) 38 (11): 1019–1022. https://doi.org/10.1130/G31491.1 Article history received: 21 Jun 2010 rev-recd: 22 Jun 2010 first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation N.L. Bangs, M.J. Hornbach, G.F. Moore, J.-O. Park; Massive methane release triggered by seafloor erosion offshore southwestern Japan. Geology 2010;; 38 (11): 1019–1022. doi: https://doi.org/10.1130/G31491.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Vast amounts of methane hydrate exist beneath continental margins, but whether this methane releases from sediment on a large scale and affects the oceans and atmosphere remains unclear. Analysis of newly acquired three-dimensional seismic images and drilling data from a large gas hydrate province reveal a recently eroded v-shaped depression. The depression sharply cuts through a relic bottom simulating reflection (BSR) and hydrate-laden sediments. The shape of the relic BSR indicates that the seafloor depression was once a large anticline that has recently been eroded and released an estimated 1.51 × 1011 m3 of methane. We hypothesize that erosion of the seafloor via bottom-water currents unroofed buoyant hydrate-laden sediments and subhydrate overpressured free gas zones beneath the anticline. Once triggered, gas-driven erosion created a positive feedback mechanism, releasing gas and eroding hydrate-bearing sediment. We suggest that erosive currents in deep-water methane hydrate provinces act as hair triggers, destabilizing kilometer-scale swaths of the seafloor where large concentrations of underlying overpressured methane exist. Our analysis suggests that kilometer-scale degassing events are widespread, and that deep-water hydrate reservoirs can rapidly release methane in massive quantities. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.