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GEOPHYSICAL RESEARCH LETTERS, VOL. 30, NO. 7, 1398, doi:10.1029/2002GL016658, 2003

Methane escape from gas hydrate systems in marine environment, and methane-driven oceanic eruptions

Youxue Zhang

Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan, USA

Abstract

Huge quantities of CH₄ are stored in marine sediment in the form of methane hydrate, bubbles, and dissolved CH₄ in pore water. Here I discuss the various pathways for methane to enter the ocean and atmosphere, including: (i) Methane hydrate dissolution or dissociation as it rises through seawater. The dissociation rate can be 2 to 3 orders of magnitude greater than the dissolution rate. (ii) The dissolution and expansion of a bubble with or without a hydrate shell as it rises through seawater. There is a critical radius (which depends on depth), above which a bubble would reach the surface or even become larger as it rises. I also propose and model the dynamics of a new type of terrestrial gas-driven eruptions: methane-driven oceanic eruptions. Such eruptions not only represent a yet unrecognized geohazard, but also provide a pathway for CH₄ to rapidly enter the atmosphere as a greenhouse gas.

Published 10 April 2003.

Index Terms: 3099 Marine Geology and Geophysics: General or miscellaneous; 4568 Oceanography: Physical: Turbulence, diffusion, and mixing processes; 8414 Volcanology: Eruption mechanisms; 8450 Volcanology: Planetary volcanism (5480); 9810 General or Miscellaneous: New fields (not classifiable under other headings).

Subscriber Access to Full Article (Nonsubscribers may purchase for $9.00, Includes print PDF, file size: 274350 bytes)

Citation: Zhang, Y. (2003), Methane escape from gas hydrate systems in marine environment, and methane-driven oceanic eruptions, Geophys. Res. Lett., 30(7), 1398, doi:10.1029/2002GL016658.

Copyright 2003 by the American Geophysical Union.