| Publication type: |
 |
Article in peer-reviewed journal |
|
| Subject: |
|
|
|
| Title: |
|
Slip rate and slip magnitudes of past earthquakes along the Bogd left-lateral strike-slip fault (Mongolia) |
|
| Author(s): |
|
Magali Rizza ( ) 1, Jean-françois RITZ () 1, R. Braucher 2, Riccardo Vassallo 3, C. Prentice 4, S. Mahan 5, S. Mcgill 6, Alain CHAUVET () 1, S. Marco 7, M. Todbileg 8, S. Demberel 9, D. Bourles 2 |
|
| Laboratory: |
|
| 1: |
Géosciences Montpellier (GM) |
|
|
CNRS : UMR5243 – Université Montpellier II - Sciences et techniques |
|
|
Place E. Bataillon - CC 60 34095 MONTPELLIER CEDEX 5 |
|
|
France |
|
| 2: |
Centre européen de recherche et d'enseignement de géosciences de l'environnement (CEREGE) |
|
|
http://www.cerege.fr |
|
|
CNRS : UMR6635 – Institut de recherche pour le développement [IRD] – INSU – Université de Provence - Aix-Marseille I – Université Paul Cézanne - Aix-Marseille III |
|
|
CEREGE EUROPOLE MEDITERR. DE L'ARBOIS - BP 80 13545 AIX EN PROVENCE CEDEX 4 |
|
|
France |
|
| 3: |
Institut des sciences de la Terre (ISTerre) |
|
|
http://isterre.fr/ |
|
|
CNRS : UMR5275 – IFSTTAR – Université de Savoie – Université Joseph Fourier - Grenoble I – INSU – OSUG – Institut de recherche pour le développement [IRD] : UR219 |
|
|
BP 53 38041 Grenoble cedex 9 |
|
|
France |
|
| 4: |
US Geological Survey (USGS) |
|
|
US Geological Survey, Menlo Park |
|
|
345 Middlefield Rd MS 977, Menlo Park, CA 94025, USA |
|
|
United States |
|
| 5: |
US Geological Survey (USGS) |
|
|
Denver Federal Center |
|
|
Box 25046, MS 974, Denver, CO 80225, USA |
|
|
United States |
|
| 6: |
Department of Geological Sciences |
|
|
California State University |
|
|
San Bernardino, CA 92407, USA |
|
|
United States |
|
| 7: |
Department of Geophysics and Planetary Sciences |
|
|
Tel Aviv University |
|
|
Tel Aviv 69978 |
|
|
Israel |
|
| 8: |
Mongolian University of Science and Technology |
|
|
Mongolian University of Science and Technology |
|
|
P.O. Box 46/433, Ulaanbaatar, 210646, Mongolia |
|
|
Mongolia |
|
| 9: |
Researcher Centre of Astronomy and Geophysics (RCAG) |
|
|
Academy of Sciences of Mongolia |
|
|
P.O. Box 152, Ulaanbaatar 51, Mongolia |
|
|
Mongolia |
|
|
| Research team: |
|
Risques
Tectonique reliefs et bassins
Bassins |
| Abstract: |
|
We carried out morphotectonic studies along the left-lateral strike-slip Bogd Fault, the principal structure involved in the Gobi-Altay earthquake of 1957 December 4 (published magnitudes range from 7.8 to 8.3). The Bogd Fault is 260 km long and can be subdivided into five main geometric segments, based on variation in strike direction. West to East these segments are, respectively: the West Ih Bogd (WIB), The North Ih Bogd (NIB), the West Ih Bogd (WIB), the West Baga Bogd (WBB) and the East Baga Bogd (EBB) segments. Morphological analysis of offset streams, ridges and alluvial fans-particularly well preserved in the arid environment of the Gobi region-allows evaluation of late Quaternary slip rates along the different faults segments. In this paper, we measure slip rates over the past 200 ka at four sites distributed across the three western segments of the Bogd Fault. Our results show that the left-lateral slip rate is similar to 1 mm yr(-1) along the WIB and EIB segments and similar to 0.5 mm yr(-1) along the NIB segment. These variations are consistent with the restraining bend geometry of the Bogd Fault.;Our study also provides additional estimates of the horizontal offset associated with the 1957 earthquake along the western part of the Bogd rupture, complementing previously published studies. We show that the mean horizontal offset associated with the 1957 earthquake decreases progressively from 5.2 m in the west to 2.0 m in the east, reflecting the progressive change of kinematic style from pure left-lateral strike-slip faulting to left-lateral-reverse faulting. Along the three western segments, we measure cumulative displacements that are multiples of the 1957 coseismic offset, which may be consistent with a characteristic slip. Moreover, using these data, we re-estimate the moment magnitude of the Gobi-Altay earthquake at M-w 7.78-7.95.;Combining our slip rate estimates and the slip distribution per event we also determined a mean recurrence interval of similar to 2500-5200 yr for past earthquakes along the different segments of the western Bogd Fault. This suggests that the three western segments of the Bogd Fault and the Gurvan Bulag thrust fault (a reverse fault bounding the southern side of the Ih Bogd range that ruptured during the 1957 earthquake) have similar average recurrence times, and therefore may have ruptured together in previous earthquakes as they did in 1957. These results suggest that the western part of the Bogd Fault system, including the Gurvan Bulag thrust fault, usually behaves in a 'characteristic earthquake' mode. |
|
| Fulltext language: |
|
English |
|
|
| Journal: |
|
|
|
| Audience: |
|
international |
|
| Publication date: |
|
2011-09-12 |
|
| Volume: |
|
186 |
|
| Issue: |
|
3 |
|
| Page, identifiant, ...: |
|
pp.897-927 |
|
|
| Keyword(s): |
|
Seismic cycle – Geomorphology – Earthquake dynamics – Continental neotectonics – Continental tectonics – strike-slip and transform – Asia |
|
| Internal note: |
|
GM:11-070 |
|
|
| Contract, financing: |
|
French INSU 3F ('Failles, Fluides, Flux') 2007 program. |
|
Export this paper
