Hypocenter relocation analysis of 7.5 Mw Palu and its aftershocks: A preliminary result

Abstract

The earthquake that occurred in the Palu city and its surroundings on September 28, 2018, with a magnitude of 7.5 Mw caused a lot of casualties and infrastructure damages. Tsunami and liquefaction are secondary effects that contribute significantly to these two losses. The earthquake occurred at the Palu Koro Fault with a strike-slip mechanism. The BMKG seismic network successfully recorded aftershocks caused by the earthquake. Hypocenter relocation using the double-difference method is applied in this study to analyze the mainshock and its aftershocks so that the fault geometry of the earthquake can be known clearly. This study used the BMKG earthquake catalog at coordinates 40S-10N and 1180-1220E until the end of December 2018. The results show an improvement in the hypocenter position with loss of fix depth at a depth of 10 km so that the area can be interpreted tectonically. The results also show that the majority of the earthquakes beneath the fault are at a depth of less than 25 km. The relocated hypocenter parameters are very useful as a database for further tectonic studies that are useful for earthquake disaster mitigation in the area.

Hypocenter Relocation of Local Earthquake using Double Difference Method in Central Sulawesi from BMKG Network Data: Time Periods of July 26 - August 18, 2021

“…In carrying out the hypocenter relocation process, many researchers have used and obtained maximum results, both in Central Sulawesi and Indonesia. This method can be used in earthquake relocation due to faults and subduction zones [15][16][17][18], for relocation of small earthquakes caused by volcanic activity [19,20], and due to vibration at mining sites [21,22].…”