Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Geology Signup for GSW Email News
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Geology; February 2004; v. 32; no. 2; p. 101-104; DOI: 10.1130/G19993.1
© 2004 Geological Society of America
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Zühlsdorff, L.
Right arrow Articles by Spieß, V.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation

Three-dimensional seismic characterization of a venting site reveals compelling indications of natural hydraulic fracturing

L. Zühlsdorff1 and V. Spieß1

1 Earth Sciences Department, Bremen University, Klagenfurterstrasse, 28359 Bremen, Germany

Based on a three-dimensional high-resolution seismic survey off Vancouver Island, Canada, we show that natural hydraulic fracturing is an efficient process to create permeable pathways for focused fluid upflow at submarine venting sites. The pockmark structure examined in this study is located on top of an accreted ridge, where the low-permeability base of the gas hydrate stability field is also elevated, and fluid overpressure will be induced tectonically. Elongated hydraulic fractures reveal decreased reflection amplitudes and are oriented along the maximum principal stress direction, perpendicular to nearby fault planes. A surface expression is created by fluid and material expulsion, forming an irregular, noncircular rim along the axis of the upflow zone. Our findings confirm a relationship between lateral variations in seismic reflectivity and sediment distribution, regional tectonics, episodic fluid flow, and the formation and dissociation of gas hydrate. They explain the presence of gas hydrate at the top of the upflow zone, which requires transport of large volumes of gas through the gas hydrate stability field. Since hydraulic fracturing is not restricted to compressional regimes, it is a likely explanation for the nature, shape, and orientation of upflow zones as well as for seismic blanking widely observed at both active and passive continental margins.

Key Words: three-dimensional methods • seismic data • hydraulic fracturing • gas hydrates • fluids • pockmarks • accretionary prisms




This article has been cited by other articles:


Home page
 GeologyHome page
R.R. Haacke, R.D. Hyndman, K-P. Park, D-G. Yoo, I. Stoian, and U. Schmidt
Migration and venting of deep gases into the ocean through hydrate-choked chimneys offshore Korea
Geology, June 1, 2009; 37(6): 531 - 534.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society, London, Special PublicationsHome page
M. Riedel, T. Collett, M. J. Malone, and IODP Expedition 311 Scientists
Gas hydrate drilling transect across northern Cascadia margin - IODP Expedition 311
Geological Society, London, Special Publications, January 1, 2009; 319(1): 11 - 19.
[Abstract] [Full Text] [PDF]

Home page
 Geological Society of America BulletinHome page
M. Riedel, I. Novosel, G. D. Spence, R. D. Hyndman, R. N. Chapman, R. C. Solem, and T. Lewis
Geophysical and geochemical signatures associated with gas hydrate-related venting in the northern Cascadia margin
Geological Society of America Bulletin, January 1, 2006; 118(1-2): 23 - 38.
[Abstract] [Full Text] [PDF]


JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Geological Society of America