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Earthquake in a Maze: Compressional Rupture Branching During the 2012 M_w 8.6 Sumatra Earthquake

Meng, L. and Ampuero, J.-P. and Stock, J. and Duputel, Z. and Luo, Y. and Tsai, V. C. (2012) Earthquake in a Maze: Compressional Rupture Branching During the 2012 M_w 8.6 Sumatra Earthquake. Science, 337 (6095). pp. 724-726. ISSN 0036-8075. doi:10.1126/science.1224030.

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Seismological observations of the 2012 moment magnitude 8.6 Sumatra earthquake reveal unprecedented complexity of dynamic rupture. The surprisingly large magnitude results from the combination of deep extent, high stress drop, and rupture of multiple faults. Back-projection source imaging indicates that the rupture occurred on distinct planes in an orthogonal conjugate fault system, with relatively slow rupture speed. The east-southeast–west-northwest ruptures add a new dimension to the seismotectonics of the Wharton Basin, which was previously thought to be controlled by north-south strike-slip faulting. The rupture turned twice into the compressive quadrant, against the preferred branching direction predicted by dynamic Coulomb stress calculations. Orthogonal faulting and compressional branching indicate that rupture was controlled by a pressure-insensitive strength of the deep oceanic lithosphere.

Item Type:Article
Related URLs:
URLURL TypeDescription
Meng, L.0000-0003-2428-0548
Ampuero, J.-P.0000-0002-4827-7987
Stock, J.0000-0003-4816-7865
Luo, Y.0000-0002-1165-6107
Tsai, V. C.0000-0003-1809-6672
Additional Information:© 2012 American Association for the Advancement of Science. Received 30 April 2012; accepted 5 July 2012. Published Online July 19 2012. This research was supported by NSF grant EAR-1015704, by the Gordon and Betty Moore Foundation, and by the Southern California Earthquake Center (SCEC), which is funded by NSF Cooperative Agreement EAR-0106924 and USGS Cooperative Agreement 02HQAG0008. The Japanese Hi-net ( and the European ORFEUS ( data centers were used to access the broadband seismograms. The magnetic anomalies are from the EMAG2 database available at the National Geophysical Data Center ( The satellite gravity anomaly data are from the UCSD TOPEX v. 18.1 database. The multibeam bathymetry from the KNOX06RR cruise is available at Marine Geoscience Data System ( We thank R.-C. Lien and B. Ma for providing the Roger Revelle (RR1201) multibeam data from the DYNAMO cruise. We thank H. Kanamori for valuable discussions about this event. This paper is Caltech Tectonics Observatory contribution 215, Caltech Seismo Lab contribution 10078, and SCEC contribution 1656.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
Southern California Earthquake Center (SCEC)UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory215
Caltech Division of Geological and Planetary Sciences10078
Southern California Earthquake Center1656
Issue or Number:6095
Record Number:CaltechAUTHORS:20120816-082822417
Persistent URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:33251
Deposited By: Tony Diaz
Deposited On:16 Aug 2012 18:36
Last Modified:09 Nov 2021 21:33

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