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Evidence for fault lubrication during the 1999 Chi-Chi, Taiwan, earthquake (Mw7.6)

Ma, Kuo-Fong and Brodsky, Emily E. and Mori, Jim and Ji, Chen and Song, Teh-Ru A. and Kanamori, Hiroo (2003) Evidence for fault lubrication during the 1999 Chi-Chi, Taiwan, earthquake (Mw7.6). Geophysical Research Letters, 30 (5). Art. No. 1244. ISSN 0094-8276. doi:10.1029/2002GL015380.

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The ground motion data of the 1999 Chi-Chi, Taiwan, earthquake exhibit a striking difference in frequency content between the north and south portions of the rupture zone. In the north, the ground motion is dominated by large low-frequency displacements with relatively small high-frequency accelerations. The pattern is opposite in the south, with smaller displacements and larger accelerations. We analyze the fault dynamics in light of a fault lubrication mechanism using near-field seismograms and a detailed rupture model. The fault zone contains viscous material (e.g., gouge), in which pressure increases following the Reynolds lubrication equation. When the displacement exceeds a threshold, lubrication pressure becomes high enough to widen the gap, thereby reducing the area of asperity contact. With less asperity contact, the fault slips more smoothly, suppressing high-frequency radiation.

Item Type:Article
Related URLs:
URLURL TypeDescription
Brodsky, Emily E.0000-0002-6855-6860
Ji, Chen0000-0002-0350-5704
Song, Teh-Ru A.0000-0003-3697-5881
Kanamori, Hiroo0000-0001-8219-9428
Additional Information:Copyright 2003 by the American Geophysical Union. Received 25 April 2002; revised 19 July 2002; accepted 27 December 2002; published 13 March 2003. We are grateful to the Central Weather Bureau, Taiwan, for providing excellent strong motion records. The suggestions of two anonymous reviewers have been very helpful. This work was supported by National Science Council grant: NSC90-2119-M-008-015.
Funding AgencyGrant Number
National Science Council (Taipei)NSC90-2119-M-008-015
Subject Keywords:Chi-Chi Taiwan earthquake, high slip velocity, nearfield strong motion station, fault dynamics, fault lubrication, fluid pressurization
Issue or Number:5
Classification Code:7209 Seismology: Earthquake dynamics and mechanics; 7212 Seismology: Earthquake ground motions and engineering; 7215 Seismology: Earthquake parameters
Record Number:CaltechAUTHORS:20141027-113157551
Persistent URL:
Official Citation:Ma, K.-F., E. E. Brodsky, J. Mori, C. Ji, T.-R. A. Song, and H. Kanamori, Evidence for fault lubrication during the 1999 Chi-Chi, Taiwan, earthquake (Mw7.6), Geophys. Res. Lett., 30(5), 1244, doi:10.1029/2002GL015380, 2003.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50850
Deposited By: George Porter
Deposited On:27 Oct 2014 20:01
Last Modified:10 Nov 2021 19:01

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