FN Archimer Export Format PT J TI Impact of lower plate structure on upper plate deformation at the NW Sumatran convergent margin from seafloor morphology BT AF GRAINDORGE, D KLINGELHOEFER, Frauke SIBUET, Jean-Claude MCNEILL, L HENSTOCK, T DEAN, S GUTSCHER, M DESSA, J PERMANA, H SINGH, S LEAU, H WHITE, N CARTON, H MALOD, Jacques-Andre RANGIN, C ARYAWAN, K CHAUBEY, A CHAUHAN, A GALIH, D GREENROYD, C LAESANPURA, A PRIHANTONO, J ROYLE, G SHANKAR, U AS 1:1;2:2;3:2;4:3;5:3;6:3;7:1;8:4;9:5;10:6;11:7;12:8;13:6;14:1;15:9;16:10;17:;18:6;19:5;20:11;21:12;22:13;23:6;24:14; FF 1:;2:PDG-DOP-DCB-GM-LGG;3:;4:;5:;6:;7:;8:;9:;10:;11:;12:;13:;14:;15:;16:;17:;18:;19:;20:;21:;22:;23:;24:; C1 UBO IUEM, UMR Domaines Ocean 6538, F-29280 Plouzane, France. IFREMER, Brest, France. Univ Southampton, Natl Oceanog Ctr, Southampton, Hants, England. UPMC, UMR Geosci Azur, Nice, France. Indonesia Inst Sci, Geotech Res Ctr, Earth Dynam & Geol Disaster Div, Bandung, Indonesia. Inst Phys Globe, Paris, France. Inst Polaire Paul Emile Victor IPEV, Brest, France. Bullard Labs, Cambridge, England. Coll France, CNRS, Aix En Provence, France. Marine Geol Inst, Energy & Earth Resources Dept, Bandung, Indonesia. Univ Durham, Durham, England. ITB, Bandung, Indonesia. Marine & Fishery Dept, Jakarta, Indonesia. NGRI, Hyderabad, Andhra Pradesh, India. C2 UBO, FRANCE IFREMER, FRANCE NOC, UK UNIV PARIS 06, FRANCE INDONESIA INST SCI, INDONESIA IPGP, FRANCE IPEV, FRANCE BULLARD LABS, UK COLL FRANCE, FRANCE MARINE GEOL INST, INDONESIA UNIV DURHAM, UK ITB, INDONESIA MARINE & FISHERY DEPT, INDONESIA NGRI, INDIA SI BREST SE PDG-DOP-DCB-GM-LGG PDG-DOP-DCB-GM IN WOS Ifremer jusqu'en 2018 copubli-france copubli-europe copubli-univ-france copubli-int-hors-europe copubli-sud IF 3.955 TC 58 TU Centre national de la recherche scientifique Institut de recherche pour le développement Institut français de recherche pour l'exploitation de la mer Service Hydrographique et Océanographique de la Marine Université de Bretagne Occidentale Université de Bretagne-Sud UR https://archimer.ifremer.fr/doc/2008/publication-5166.pdf LA English DT Article CR MD 156 / SUMATRA-OBS MD149 / SUMATRA AFTERSHOCKS SAMUDRA2 BO Marion Dufresne L'Atalante DE ;Sumatra;Tectonic;Seafloor morphology;Accretionary wedge;Subduction AB We present results from multibeam bathymetric data acquired during 2005 and 2006, in the region of maximum slip of the 26 Dec. 2004 earthquake (Mw 9.2). These data provide high-resolution images of seafloor morphology of the entire NW Sumatra forearc from the Sunda trench to the submarine volcanic arc just north of Sumatra. A slope gradient analysis of the combined dataset accurately highlights those portions of the seafloor shaped by active tectonic, depositional and/or erosional processes. The greatest slope gradients are located in the frontal 30 km of the forearc, at the toe of the accretionary wedge. This suggests that long-term deformation rates are highest here and that probably only minor amounts of slip are accommodated by other thrust faults further landward. Obvious N-S oriented lineaments observed on the incoming oceanic plate are aligned sub-parallel to the fracture zones associated with the Wharton fossil spreading center. Active strike-slip motion is suggested by recent deformation with up to 20-30 m of vertical offset. The intersection of these N-S elongated bathymetric scarps with the accretionary wedge partly controls the geometry of thrust anticlines and the location of erosional features (e.g. slide scars, canyons) at the wedge toe. Our interpretation suggests that these N-S lineaments have a significant impact on the oceanic plate, the toe of the wedge and further landward in the wedge. Finally, the bathymetric data indicate that folding at the front of the accretionary wedge occurs primarily along landward-vergent (seaward-dipping) thrusts, all unusual style in accretionary wedges worldwide. The N-S elongated lineaments locally act as boundaries between zones with predominant seaward versus landward vergence. PY 2008 PD NOV SO Earth and Planetary Science Letters SN 0012-821X PU Elsevier VL 275 IS 3-4 UT 000261484400001 BP 201 EP 210 DI 10.1016/j.epsl.2008.04.053 ID 5166 ER EF