SEISMICITY RATE CHANGE AND REGION-TIME-LENGTH ALGORITHM INVESTIGATIONS ALONG THAILAND-LAOS-MYANMAR BORDERS

Abstract

In order to investigate the prospective areas of the upcoming strong earthquakes, i.e., Mw ≥ 6, the seismicity data have been posed in the vicinity of Thailand-Laos-Myanmar borders were investigated statistically. Based on the successful investigation of previous work, two statistic techniques were applied in this study, i.e., seismicity rate change (Z value) and Region-Time-Length (RTL) algorithm. According to the completeness of the earthquake data, the available 8 case studies of strong earthquakes were investigated retrospectively. Regarding to the Z value, the condition of time window = 1.2 years, the number of earthquakes = 50 events, and fixed node radius = 250 km showed the locations of Z anomalies conformed to 5 of 8 earthquakes. Meanwhile, using characteristic parameters r0 = 120 km, t0 = 2 years, the RTL anomalies quite related to 5 of 8 earthquakes. Therefore, it is concluded that both Z and RTL methods applied in this study are fairly effective to evaluate the earthquake precursor. In order to evaluate the prospective area for the upcoming earthquake, both Z and RTL were analyzed with the complement by the suitable characteristic parameters mentioned above and the most up-to-date completeness seismicity data. The results reveal that the small area in the vicinity of Thailand-Myanmar border are quiescence seismically conforming to that proposed by the previous investigation of b value of the frequency-magnitude distribution. Therefore, it is concluded that according to both Z, RTL, and b value methods that the prospective areas proposed in this study might be posed by the upcoming earthquake.