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AGU: Journal of Geophysical Research, Solid Earth

 

Keywords

  • wide-angle seismic
  • heat flow
  • Sumatra

Index Terms

  • Tectonophysics: Subduction zone processes
  • Marine Geology and Geophysics: Marine seismics
  • Seismology: Subduction zones
  • Seismology: Earthquake dynamics
  • Tectonophysics: Heat generation and transport
Abstract
Cited By (5)
 

Abstract

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 115, B01304, 23 PP., 2010
doi:10.1029/2009JB006569

Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling

F. Klingelhoefer

Department of Marine Geosciences, Ifremer, Plouzané, France

M.-A. Gutscher

UMR 6538, Domaines Océaniques, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France

S. Ladage

Federal Institute for Geosciences and Natural Resources, Hanover, Germany

J.-X. Dessa

Géosciences Azur, UMR 6526, Observatoire Océanologique de Villefranche, Université Pierre et Marie Curie, CNRS, Villefranche sur Mer, France

D. Graindorge

UMR 6538, Domaines Océaniques, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France

D. Franke

Federal Institute for Geosciences and Natural Resources, Hanover, Germany

C. André

UMR 6538, Domaines Océaniques, Université de Bretagne Occidentale, Institut Universitaire Européen de la Mer, Plouzané, France

H. Permana

Earth Dynamics and Geological Disaster Division, Research Center for Geotechnology, Indonesia Institute of Sciences, Bandung, Indonesia

T. Yudistira

Program Studi Teknik Geofisika, Institut Teknologi Bandung, Bandung, Indonesia

A. Chauhan

Laboratoire de Géosciences Marines, Institut de Physique du Globe de Paris, Paris, France

The 26 December 2004 Sumatra earthquake (Mw = 9.1) initiated around 30 km depth and ruptured 1300 km of the Indo-Australian–Sunda plate boundary. During the Sumatra-OBS (ocean bottom seismometer) survey, a wide-angle seismic profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore-arc basin. A high-velocity zone at the lower landward limit of the ray-covered domain, at 22 km depth, marks a shallow continental Moho, 170 km from the trench. The deep structure obtained from the seismic data was used to construct a thermal model of the fore arc in order to predict the limits of the seismogenic zone along the plate boundary fault. Assuming 100°–150°C as its updip limit, the seismogenic zone is predicted to begin 5–30 km from the trench. The downdip limit of the 2004 rupture as inferred from aftershocks is within the 350°–450°C temperature range, but this limit is 210–250 km from the trench axis and is much deeper than the fore-arc Moho. The deeper part of the rupture occurred along the contact between the mantle wedge and the downgoing plate.

Received 27 April 2009; accepted 15 September 2009; published 27 January 2010.

Citation: Klingelhoefer, F., M.-A. Gutscher, S. Ladage, J.-X. Dessa, D. Graindorge, D. Franke, C. André, H. Permana, T. Yudistira, and A. Chauhan (2010), Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling, J. Geophys. Res., 115, B01304, doi:10.1029/2009JB006569.

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