Following the Great Sumatra-Andaman Earthquake (24th December 2004) and the associated tsunami, which caused about 300 000 deaths, the Marine Geosciences Department conducted from July 15 to August 9, 2005 the «Sumatra Aftershocks» cruise on board the Marion Dufresne Research Vessel belonging to the Institut Paul-Emile Victor (IPEV). The cruise was conducted by Jean-Claude Sibuet through a cooperatve agreement with the Indonesian Agency for the Assessment and Application of Technology (BPPT). This cruise is the first of a series of oceanographic cruises belonging to the SAGER program lead by Pr Satish Singh. Financial support was provided by the Agence Nationale de la Recherche (ANR), the Délégation Inter-ministérielle pour le tsunami (DIPT), Ifremer and IPEV.

The download documents show the main operations performed at sea during the «Sumatra Aftershocks» cruise (Cruise report), the three papers dealing with the first results of this cruise and give access to the swath-bathymetric grid published in the Earth and Planetary Science Letters (EPSL) paper.

Northwest Sumatra swath-bathymetric map

The origin of data, the procedures to obtain the digital terrane model (DTM) and the characteristics of this DTM are explained in the cruise report. The 100-m space grid is available in compressed ascii format (see below) and can be used freely by referring to the Sibuet et al. (2007) EPSL paper.

The main results are discussed in the three following papers which can be downloaded in PDF format. The EOS paper (Singh and Sumatra Aftershocks Team, 2005) concerns the southeast prolongation of the West Andaman Fault. The EPSL paper (Sibuet et al., 2007) gives the geodynamical context of the studied area (from the Sunda trench in the Indian Ocean to the north of the Sumatra Island) and the first results of the 24th December 2004 aftershocks data. The paper submitted in the Slope instabilities Special Issue, Miquel Canals (Ed.), International Journal of Earth Sciences (Sultan et al., 2007 submitted) is relative to a small scar located at the toe of the accretionary prism identified by Henstock et al. (2006, Geology). The excess pore pressure recorded in the vicinity of the scar using the Ifremer piezometer shows that it could have been generated at the time of the December 26, 2004 Great Sumatra Earthquake.

Papers (PDF format)

• Singh, S. and the Sumatra Aftershocks Team, 2005. Sumatra Earthquake research indicates why rupture propagated northward, EOS, 86, 497-502. (PDF - 1 Mo)

• Sibuet J.-C., C. Rangin, X. Le Pichon, S. Singh, A. Cattaneo, D. Graindorge, F. Klingelhoefer, J.-Y. Lin, J. Malod, T. Maury, J.-L. Schneider, N. Sultan, M. Umber, H. Yamaguchi and the “Sumatra aftershocks” team, 2007. 26th December 2004 Great Sumatra-Andaman Earthquake: co-seismic and post-seismic motions in northern Sumatra. Earth Planetary Science Letters, doi:10.1016/j.epsl.2007.09.005, 263, 88-103. (PDF - 3.9 Mo)

• Sultan S., Cattaneo A., Sibuet J.-C., Schneider, J.-L. and the “Sumatra Aftershocks” team, 2007 submitted. Evidence from piezometer monitoring of in situ excess pore pressure and sediment deformation generated during the December 26, 2004 Great Sumatra-Andaman Earthquake. Slope instabilities Special Issue, Miquel Canals (Ed.), International Journal of Earth Sciences. (PDF - 1.9 Mo)

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Contacts

• Jean-Claude Sibuet : scientific supervision 
• Alain Normand : technical supervision