HR: 1340h
AN: T43A-1092    [Abstracts]
TI: Co-seismic and paleo-seismic slip along the Kokoxili Mw 7.8 earthquake rupture
AU: * Van der Woerd, J
EM: jeromev@eost.u-strasbg.fr
AF: IPGS-EOST, UMR CNRS/ULP 7516, 5, Rue R. Descartes, STRASBOURG, 67000, France
AU: Klinger, Y
AF: IPGP, 4, Place Jussieu, PARIS, 75000, France
AU: Xu, X
AF: Institute of Geology, China Earthquake Administration, 63 Fuxing Road, Beijing, 100029, China
AU: LeDortz, K
AF: IPGS-EOST, UMR CNRS/ULP 7516, 5, Rue R. Descartes, STRASBOURG, 67000, France
AU: Tapponnier, P
AF: IPGP, 4, Place Jussieu, PARIS, 75000, France
AU: King, G
AF: IPGP, 4, Place Jussieu, PARIS, 75000, France
AU: Bowman, D
AF: Department of Geological Sciences, CSU, P.O. Box 6850, Fullerton, CA 92834-6850, United States
AU: Ma, W
AF: Institute of Geology, China Earthquake Administration, 63 Fuxing Road, Beijing, 100029, China
AU: Chen, W
AF: Institute of Geology, China Earthquake Administration, 63 Fuxing Road, Beijing, 100029, China
AB: Co-seismic slip values along a strike-slip rupture are found to be very irregular with variations up to one order of magnitude. Data usually scattered and sparse, are now becoming more dense and continuous with slip functions derived from InSAR or image correlations. Whether the fast variations in slip along strike reveals long- lived structures of the fault plane at depth, only incomplete slip at the surface or inelastic accommodation of slip remains debated. In addition, how these slip disparities are accommodated with time is unclear. Here we investigate the co-seismic and paleo-seismic slip of the Kunlun Fault, along the Kokoxili 14 November 2001, Mw=7.9 earthquake rupture. At one site, a set of about 10 inset terraces is used to infer the slip history of the fault. The particularly low slip value at the site, about 2.4 ± 0.6 m, lower than the value derived from Spot image correlation or from Insar, follows a maximum slip value of about 8 m only a few kilometers to the west. Site interpretation from field data and high resolution Ikonos images allow to reconstruct the different riser offsets across the damaged rupture zone. Be10 cosmogenic exposure ages of cobbles from the surface of the terraces allow to constrain the age of one of the terraces and to infer an average slip-rate of 10-15 mm/yr in good agreement with previous results along the fault. When a characteristic slip model is considered, and depending of the measurement method or location of coseismic slip, the recurrence time for events comparable to the Mw 7.8 Kokoxili event may vary from 200 to 800 years.
DE: 1130 Geomorphological geochronology
DE: 1150 Cosmogenic-nuclide exposure dating (4918)
DE: 7221 Paleoseismology (8036)
DE: 8123 Dynamics: seismotectonics
SC: Tectonophysics [T]
MN: 2007 Fall Meeting