Seismic hazard assessment in Thailand using probabilistic and deterministic methods

Abstract

In this study, the seismic hazards (SHA) in Thailand are analyzed. Fifty-five possible active fault zones identified from remote-sensing and out of those twenty-one seismic source zones are recognized to be the earthquake sources. The earthquake potential parameters used for SHA are derived from both active fault and earthquake catalogues. The strong ground-motion attenuation models are selected by comparison of the application of several candidate models with strong ground-motion data recorded in Thailand. Both deterministic (DSHA) and probabilistic (PSHA) approaches are employed in this SHA. For Thailand, there are seismic hazards in areas dominated by active fault zones such as northern, western, and southern Thailand. The DSHA map reveals seismic hazard around 0g-0.8g. In PSHA, the PGA values for 50 year in these areas are around 0.5g and 1g for 10% and 2% probability of exceedance, respectively. For Myanmar and Nicobar Islands the PSHA up to 3g in case of 2% probability of exceedance in 50 year according to the Sumatra-Andaman Subduction Zone. Comparing with the previous works the SHA of this study are higher than those proposed previously. However, this SHA compatible with the past ground shaking reported in the literatures. The SHA presented here is an important step toward an accurate evaluation of seismic hazard in Thailand. Further work is needed to refine the analysis. More observations of ground motion in the region are needed and further paleo-seismological study should be encouraged