Chiang Mai Journal of Science

An earthquake swarm occurred at Phuket Island, located in the western part of Southern Thailand, from 16 April to 22 April 2012, likely even until 5 May 2012. The earthquakes have caused slight damages to buildings on the island, and the largest event on the first day has been felt by local people and tourists prompting them to flee buildings in panic. For this study, digital seismograms recorded by seismological stations in Southern Thailand under the Thai Meteorological Department (TMD)’s network were analyzed; some event data from a previous study were added. Results show that the Phuket swarm is relatively short in duration (7 days/20 days) with 46/48 earthquakes, respectively. Seismotectonically the Phuket swarm can be linked to the active and NNE-SSE trending Khlong Marui Fault Zone, precisely to ESE dipping fault planes of its positive flower structure. Further, through GPS data the Phuket swarm might be linked to two M8+ earthquakes, which occurred five days earlier east of the Sunda Subduction Zone at the nascent plate boundary inside the Indian Australian Plate.