Return period and probability of extreme earthquake using weibull equation in Maluku Barat Daya Islands

Abstract

The geographic location of the Maluku Barat Daya islands, which is located in an area of active plate subduction, is part of the world’s volcanic activity, thus shaping this area from natural disasters. This is why over the past decade, all major natural disasters have occurred. This has been recorded through earthquake information in the Maluku Barat Daya islands since 1900-2019 with a complete of 57 earthquakes for magnitudes above 6. Statistical surveys allow research on forecasts of future earthquakes. This study aims to estimate the return period and possibly the largest earthquake in the future. The results of a seismic statistical study in the Southwest Maluku Islands show that for magnitude 7.3 it has a return period of 65 years with a probability of 1.53%, for magnitude 7.1 it has a return period of 21 years with a probability of 4.61% and for a magnitude of 6.9 have a return period. 7 year return. with a probability of 13.84%. This shows that the smaller the magnitude of an earthquake, the greater the probability value. Analysis of earthquake probability and earthquake magnitude in the next 30 years shows for magnitude 6 which has a probability value of 100%, while for magnitude 7.3, the earthquake probability will drop sharply to 37%. This means that for the next 30 years, the possibility of an earthquake with a magnitude of 6 is very likely to occur when compared with a magnitude of 7.3.