The tsunami of 2007 September 12, Bengkulu province, Sumatra, Indonesia: post-tsunami field survey and numerical modelling

The M_w =8.4 earthquake on 2007 September 12, offshore of the Bengkulu province of Sumatra, Indonesia, generated a moderate tsunami with run-up heights of up to 4 m as measured by Indonesian and international researchers in the days following the earthquake. The tsunami was observed along 250 km of coastline and caused damage at several locations. The largest wave heights and most severe inundation were observed about 50 km to the northwest of Bengkulu; elsewhere the effects were less severe-with the exception of substantial inundation at a site 150 km to the south. In addition to presenting the field data, we conduct a modelling study and compare the run-up heights and water-level predictions from four different seismic deformation models used to initialize a tsunami propagation and inundation model. Our comparative results suggest that, for this event, the estimates of fault parameters available immediately after determination of the earthquake size and location predicted the near-field run-up heights and distribution and far-field wave equally well as estimates obtained using more detailed descriptions of the seafloor deformation, as typically available hours or days after an event. We conclude that while detailed slip patterns can be important to the near-field run-up distribution, simple fault models can be used to rapidly assess the likely near- and far-field tsunami effects of a particular earthquake.