Tsunami Hazard Analysis of Future Megathrust Sumatra Earthquakes in Padang, Indonesia Using Stochastic Tsunami Simulation

Ario Muhammad,Nicholas Alexander,Katsuichiro Goda

doi:10.3389/fbuil.2016.00033

Ario Muhammad, Nicholas Alexander + Show 1 more

Open Access

https://doi.org/10.3389/fbuil.2016.00033

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Abstract

This study assesses the tsunami hazard potential in Padang, Indonesia probabilistically using a novel stochastic tsunami simulation method. The stochastic tsunami simulation is conducted by generating multiple earthquake source models for a given earthquake scenario, which are used as input to run Monte Carlo tsunami simulation. Multiple earthquake source models for three magnitude scenarios, i.e. Mw 8.5, Mw 8.75, and Mw 9.0, are generated using new scaling relationships of earthquake source parameters developed from an extensive set of 226 finite-fault models. In the stochastic tsunami simulation, the effect of incorporating and neglecting the prediction errors of earthquake source parameters is investigated. In total, 600 source models are generated to assess the uncertainty of tsunami wave characteristics and maximum tsunami wave height profiles along coastal line of Padang. The results highlight the influence of the uncertainty of the scaling relationships on tsunami simulation results and provide a greater range of tsunamigenic scenarios produced from the stochastic tsunami simulation. Additionally, the results show that for the future major earthquakes in the Sunda megathrust, the maximum tsunami wave height in Padang areas can reach 20 m and therefore, significant damage and loss may be anticipated in this region.

Highlights

Located among three major plates, namely the Indian-Australian, the Pacific, and the Eurasian, Indonesia archipelago is one of the most seismically active regions in the world
Two major seismic sources are the 1,900-km long Sumatran fault located along the center of Sumatra Island and the Sunda megathrust zone traversing more than 2,000 km along the western coast of Sumatra
The main objectives of this study are (1) to develop stochastic earthquake slip models for the future tsunamigenic earthquakes in the Mentawai segment of the Sunda subduction zone, (2) to evaluate the impact of stochastic earthquake slip on tsunami simulation results in terms of tsunami wave profiles and maximum tsunami height along the coastal line of Padang by considering the uncertainty and dependency of the earthquake source parameters, and (3) to assess the tsunami hazard in Padang using a wide range of earthquake scenarios generated from the novel stochastic tsunami simulation method

Summary

Introduction

Located among three major plates, namely the Indian-Australian, the Pacific, and the Eurasian, Indonesia archipelago is one of the most seismically active regions in the world. Sumatra Island is the most seismically active region since it is located at the interface between the Indian-Australian and Eurasian Plates. Two major seismic sources are the 1,900-km long Sumatran fault located along the center of Sumatra Island and the Sunda megathrust zone traversing more than 2,000 km along the western coast of Sumatra. In the past two decades, several large earthquakes occurred along the Sunda megathrust including the Aceh-Andaman earthquake in December 2004 (Mw 9.15), the Nias earthquake in March 2005 (Mw 8.6), two earthquakes of Bengkulu in September 2007 (Mw 8.4 and 7.9), the Mentawai tsunamigenic earthquake in October 2010 (Mw 7.7), and the Indian Ocean earthquake in April 2012 (Mw 8.6). Two of the most devastating earthquake events among those were the 2004 AcehAndaman earthquake triggering large tsunamis along the coastal line of Sumatra, Thailand, Sri Lanka, and India with the casualties of more than 250,000 people and the 2005 Nias earthquake which killed 2,000 people (Hsu et al, 2006; Banerjee et al, 2007)

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