Model for episodic flow of high-pressure water in fault zones before earthquakes

Research Article| April 01, 1993 Model for episodic flow of high-pressure water in fault zones before earthquakes J. Byerlee J. Byerlee 1U. S. Geological Survey, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Author and Article Information J. Byerlee 1U. S. Geological Survey, Menlo Park, California 94025 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1993) 21 (4): 303–306. https://doi.org/10.1130/0091-7613(1993)021<0303:MFEFOH>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation J. Byerlee; Model for episodic flow of high-pressure water in fault zones before earthquakes. Geology 1993;; 21 (4): 303–306. doi: https://doi.org/10.1130/0091-7613(1993)021<0303:MFEFOH>2.3.CO;2 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 In this model for the evolution of large crustal faults, water that originally came from the country rock saturates the initially highly porous and permeable fault zone. During shearing, the fault zone compacts and water flows back into the country rock, but the flow is arrested by silicate deposition that forms very low permeability seals between the fault zone and the country rock. Because of variations in temperature and mineralogical composition and the complex structure of the fault zone, a three-dimensional network of seals is formed in the fault zone itself; thus, the high-pressure fluid is not evenly distributed. As in deep oil reservoirs, the fluid will be confined to seal-bounded fluid compartments of various sizes and porosity that are not hydraulically connected with each other or with the hydrostatic regime in the country rock. When the seal between two of these compartments is ruptured, an electrical streaming potential will be generated by the sudden movement of fluid from the high-pressure compartment to the low-pressure compartment. When the pore pressure in the two compartments reaches its final equilibrium state, the average effective normal stress across them may be lower than it was initially, and, if the two compartments are large enough, this condition may trigger an earthquake. During an earthquake, many of the remaining seals will be ruptured, and the width of the fault zone will increase by failure of the geometric irregularities on the fault. This newly created, highly porous and permeable, but now wider fault zone will fill with water, and the process described above will be repeated. Thus, the process is an episodic one, with the water moving in and out of the fault zone, and each large earthquake should be preceded by an electrical and/or magnetic signal. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.