High tsunami risk at northern tip of Sumatra as a result of the activity of the Sumatra Fault Zone (SFZ) combined with coastal landslides
Abstract
The lesson learned from the 12 January 2010, Mw 7.0 Haiti earthquake has shown that an earthquake with strike-slip faulting can produce a significant tsunami. This occasion is rare since in the fact of the fault consist predominantly of lateral motion, which is rarely associated with significant uplift or tsunami generation. Yet, another hint from this event, that this earthquake was accompanied by a coastal landslide. Again, there were only few records of a submarine slides as a primary source that generate a tsunami. Hence, the Haiti Mw 7.0 earthquake was generated by these combined mechanisms, i.e. strike-slip faulting earthquake and coastal landslide. In reflecting this event, the Sumatra region exhibit almost identical situation, where the right lateral strike-slip faulting of Sumatra Fault Zone (SFZ) is located. In this study, we are focusing at the northern tip of SFZ at Aceh Province. The reason we focused our study at its northern tip is that, since the Sumatra-Andaman mega earthquake and tsunami on 26 December 2004, which occurred at the subduction zone, there were no records of significant earthquake along the SFZ, where at this location the SFZ is divided into two faults, i.e. Aceh and Seulimeum faults. This study aimed as a mitigation effort, if an earthquake happened at these faults, do we observe a similar result as that happened at Haiti or not. To do so, we access the high-resolution shallow bathymetry data that acquired through a Community-Based Bathymetric Survey (CBBS), examines five scanned Single Channel Seismic (SCS) reflections data, perform the slope stability analysis and that simulate the tsunami using Cornell Multi-grid Coupled Tsunami Model (COMCOT) model with a combined source of fault activity and submarine landslide. The result shows that, by these combined mechanisms, if the earthquake as large as 7 Mw or larger, it could produce a tsunami as high as 6 meters along the coast. The detailed shallow bathymetric and the slope stability results indicate that the slope is close to failure and that the SCS reflection shows a turbidites type unconformity that indicate an evidence of past submarine landslide. We concluded that, there is a high risk of an event that is similar to Haiti occurred at Aceh province.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.T52B..08H
- Keywords:
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- 9320 Asia;
- GEOGRAPHIC LOCATION;
- 7221 Paleoseismology;
- SEISMOLOGY;
- 8107 Continental neotectonics;
- TECTONOPHYSICS;
- 8175 Tectonics and landscape evolution;
- TECTONOPHYSICS