Seismic activities in Kanchanaburi: Past and present

Abstract

Seismic activities in Kanchanaburi Province of the western Thailand have been a major concern among the Thai public due to the fear that a big earthquake caused by the Three Pagodas Fault Zones (TPFZ) and the Sri Sawat Fault Zone (SSFZ), one of the largest active fault zones in Thailand, could damage the large dams and generate a great disaster to the communities. Four hundred and thirty seven earthquakes that occurred in Kanchanaburi since 1983 have been analyzed for the time and location distributions along with the frequency magnitude relationship. There are no clear correlations between the epicenters of these earthquakes and the known locations of the active faults in the region. The seismic catalog used in this study is complete for M w =3.0 for Kanchanaburi region. The analysis of G-R relationship yields a-value of 5.15 and b-value of 0.86. A deterministic seismic hazard analysis of the TPFZ and SSFZ suggests that the characteristic earthquakes magnitudes of the TPFZ and the SSFZ are 7.3 and 7.0, respectively, with a maximum PGA of 0.31 and 0.28 g at the faults lines for the earthquake occurring at 15 km depth.