Spatial correlation of the maximum shear strain loading rate and the correlation dimension along the Sumatra subduction margin for potential earthquake and tsunami hazard study and analysis

Abstract

ABSTRACTThe potential earthquake and tsunami hazard along the Sumatra subduction margin, especially around the coast of West Sumatra-Bengkulu, was investigated based on the availability of pre-seismic surface displacement data and shallow crustal earthquake catalogue data from 1907 to 2016. The pre-seismic surface displacement data is based on the displacement data prior to and corrected displacement data after major earthquakes. Using the results of our previous study on the local covariance function and the relationship of Correlation Dimension (DC) with the b-value of Gutenberg-Richter (GR) Law, we estimated the maximum horizontal crustal strain rate (SHmax) and DC around the study area. Least squares prediction based on horizontal displacement data using the local covariance function is used to estimate the displacement model in the entire gridding study area with a 10 km × 10 km size. Furthermore, DC is calculated based on the b-value using the maximum likelihood method based on the input of a constant number of earthquake samples, assuming the regional b-value of GR Law equals 1. Furthermore, the spatial correlation of SHmax and DC can define the area of possible earthquake hazard potential. The identification results are then linked with previous stress reconstruction results for seismic hazard study and analysis. Based on the finding, we then estimate the Seismic Hazard Function (SHF) and Tsunami Height simulation to estimate the possible hazard risk at several observation points. We suggest that the result of this study could be beneficial to understand better the potential seismic and tsunami hazard in the future, mainly to support mitigation purposes.

Keywords

• Earthquake and tsunami potential hazard
• maximum horizontal strain rate
• correlation dimension
• b-value