Morphological Response of Coastal Ridge to Large Earthquakes along the Sumatran Subduction Zone

Dr. Ella Meilianda

Tsunami and Disaster Mitigation Research Center (TDMRC)

Syiah Kuala University, Banda Aceh, Indonesia

Late Holocene coastal morphology along the western Sumatran coast characterized by prograding beach ridge and swale morphology.  This study presents some findings from the multi-temporal geodetic monitoring surveys of the most-recent beach ridge response to co-seismic land subsidence and the sediment redistribution by the post-seismic gradual uplift after the large earthquake and tsunami of December 2004. It may explain the sediment transport mechanism at the early stage of a long-term progradation of the alternating shore-parallel ridges and swales by the mechanisms of recurrent co-seismic and post-seismic sediment transport; apart from the well-known sediment transport mechanism in a non-tectonically active coastal region.