HR: 09:00h
AN: T41E-05    [Abstracts]
TI: Slip rate of the Wadi Araba fault, southern segment of the Dead Sea fault, derived from GPS and geomorphic measurements
AU: * Klinger, Y
EM: klinger@ipgp.jussieu.fr
AF: Institut de Physique du Globe Paris, BP89, 4 place Jussieu, Paris, 75005, France
AU: Lebeon, M
EM: lebeon@ipgp.jussieu.fr
AF: Institut de Physique du Globe Paris, BP89, 4 place Jussieu, Paris, 75005, France
AU: Amrat, A
AF: Natural Ressources Authority, PO box 7, Amman, 11118, Jordan
AU: Agnon, A
EM: amotz@cc.huji.ac.il
AF: Hebrew University of Jerusalem, Givat Ram, Jerusalem, 91904, Israel
AU: Meriaux, A
EM: a.s.meriaux@ncl.ac.uk
AF: School of Geography, Politics and Sociology, Univ. Newcastle, Claremont Road, Newcastle Upon tyne, NE17RU, United Kingdom
AU: Dorbath, L
EM: louis.dorbath@eost.univ-strasbg.fr
AF: EOST, 5 rue Descartes, Strasbourg, 67000, France
AU: Baer, G
AF: Geological Survey of Israel, 30 Malkhe Yisrael St., Jerusalem, 95501, Israel
AU: Finkel, R
EM: rfinkel@llnl.gov
AF: LLNL, 7000 East Ave, Livermore, CA 94550-9234, United States
AU: Ruegg, J
EM: ruegg@ipgp.jussieu.fr
AF: Institut de Physique du Globe Paris, BP89, 4 place Jussieu, Paris, 75005, France
AU: Charade, O
EM: charade@ipgp.jussieu.fr
AF: Institut de Physique du Globe Paris, BP89, 4 place Jussieu, Paris, 75005, France
AU: Mayyas, O
EM: mayyasomar@yahoo.com
AF: Natural Ressources Authority, PO box 7, Amman, 11118, Jordan
AU: Ryerson, F
AF: LLNL, 7000 East Ave, Livermore, CA 94550-9234, United States
AU: Tapponnier, P
EM: tapponnier@ipgp.jussieu.fr
AF: Institut de Physique du Globe Paris, BP89, 4 place Jussieu, Paris, 75005, France
AB: The Dead Sea Fault (DSF) accommodates the northward displacement of the Arabia plate relative to Sinai. Although it counts among the major strike-slip faults, no agreement has been reached yet about its slip rate, either instantaneous or longer term. Proposed values vary from 2 to 10 mm/yr. We present here an extensive study of the slip rate for the southern segment of DSF, Wadi Araba fault, based on GPS profiles and measurements of offset geomorphologic features, which ages are comprised between 10 and 350 kyr. We installed 17 campaign-style GPS sites distributed along 3 profiles perpendicular to Wadi Araba fault with far-field points up to 90 km away from the fault. The sites have been measured twice, in 1999 and in 2005, during 48h- long sessions. Measurements are complemented by data from permanent GPS stations in Israel. Using a locked fault model, we estimate the slip rate to be 4.9 ± 1.6 mm/yr over 6 years. Tests for possible creep on the fault show that if it exists it is not significant. To estimate the slip rate over longer periods of time, we targeted alluvial fans offset by the fault at 4 sites, that we mapped and sampled for 10Be cosmogenic dating. At one site, preferred offset of 46 ± 4 m of a surface dated at 11 ± 3 kyr yields a slip rate of 4.7 ± 1.9 mm/yr, in very good agreement with the present-day slip rate. At the other sites, preliminary reconstructions show offsets of ~600 m to ~5400 m with ages ranging from 50 to 350 kyr and suggest a preliminary slip rate of 4-9 mm/yr. Ongoing studies aim to better understand the history of the different lobes of the fans, from their emplacement to their abandonment, to reach a tighter constraint on the geomorphologic slip rate. Interestingly, the slip rates presented here, that have been determined along the same transects of the DSF, show good agreement despite differences of methodology (GPS and geomorphology). It suggests that discrepancies between slip rates determined at different time scales could be due to misunderstanding of fault behaviors at different time scales rather than due to methodologies.
DE: 1105 Quaternary geochronology
DE: 1209 Tectonic deformation (6924)
DE: 8111 Continental tectonics: strike-slip and transform
SC: Tectonophysics [T]
MN: 2007 Fall Meeting