Earthquake Activities in the Thailand-Laos-Myanmar Border Region: A Statistical Approach


A large number of earthquakes have been recorded by instrument in the past along the Thailand-Laos-Myanmar border region. However, the locations of most of these earthquakes do not coincide with the location of morphological features which indicate seismogenic faults. Thus, a statistical evaluation of the earthquake record is focused upon in this earthquake hazard study. The spatial distributions of the a- and b-values from the frequency-magnitude distribution relationship were investigated from the complete earthquake catalogue.

 Analyses of the possible maximum magnitude earthquakes derived from the a- and b-values indicate that the northern part of Mong Pan and the Pak Beng-Luang Prabang areas are capable of generating an earthquake annually with a mb of 4.0 - 5.0 and that an earthquake of mb 7.0 is possible within 50 years. In addition, with respect to earthquakes with mb within 4.0 - 7.0, the calculated short return periods of earthquakes are located in the northern area of Mong Pan (i.e., 1 - 500 years), while the eastern part of Chiang Mai reveals a very long return period up to 5000 years.

 With respect to earthquake predictions, the three tested sub-datasets showed a good correlation between a low b-value area and the occurrence of a subsequent large earthquake in that region. Thus, based on this effective condition and present-day data, it is possible that a forthcoming earthquake may occur at the northern part of Mong Pan and the Pak Beng-Luang Prabang dams.

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