Seismic hazards in Thailand: a compilation and updated probabilistic analysis

Santi Pailoplee,Punya Charusiri

doi:10.1186/s40623-016-0465-6

Abstract

A probabilistic seismic hazard analysis (PSHA) for Thailand was performed and compared to those of previous works. This PSHA was based upon (1) the most up-to-date paleoseismological data (slip rates), (2) the seismic source zones, (3) the seismicity parameters (a and b values), and (4) the strong ground-motion attenuation models suggested as being suitable models for Thailand. For the PSHA mapping, both the ground shaking and probability of exceedance (POE) were analyzed and mapped using various methods of presentation. In addition, site-specific PSHAs were demonstrated for ten major provinces within Thailand. For instance, a 2 and 10 % POE in the next 50 years of a 0.1–0.4 g and 0.1–0.2 g ground shaking, respectively, was found for western Thailand, defining this area as the most earthquake-prone region evaluated in Thailand. In a comparison between the ten selected specific provinces within Thailand, the Kanchanaburi and Tak provinces had comparatively high seismic hazards, and therefore, effective mitigation plans for these areas should be made. Although Bangkok was defined as being within a low seismic hazard in this PSHA, a further study of seismic wave amplification due to the soft soil beneath Bangkok is required.

Highlights

At present, much evidence supports the idea that Thailand is an earthquake-prone area
Remarks: seismic source zones (SSZs) seismic source zone, FZ fault zone, RI recurrence interval, POE probability of exceedance motions that had been recorded in northern Thailand, the attenuation models of Kobayashi et al (2000) and Petersen et al (2004) were applied for shallow crustal and subduction zone earthquakes, respectively, to derive the maps for a 2 and 10 % POE in the 50 years
The results indicate that the attenuation models developed by Idriss (1993) and Crouse (1991) are the most suitable models for shallow crustal and subduction zone earthquakes, respectively, generated in mainland Southeast Asia

Summary

Introduction

Much evidence supports the idea that Thailand is an earthquake-prone area. Based on 10 seismic source zones (SSZs), 18 active faults in Thailand, and various weighting schemes in attenuation models (Youngs et al 1997; Atkinson and Boore 2006), they developed the maps of Thailand showing the 2 and 10 % POE of PGA values in the 50 years.

Results

Conclusion