Hypocenter Relocation along the Sunda Arc in Indonesia

The tectonics of the Sunda arc region is characterized by the junction of the Eurasian and IndoAustralian tectonic plates, causing complex dynamics to take place. High-seismicity rates in the Indonesian region occur due to the interaction between these tectonic plates. Prof. Dr. Andri Dian Nugraha, scientist at Global Geophysics Research Group of ITB lead a study of Hypocenter Relocation along the Sunda Arc in Indonesia, Using a 3D SeismicVelocity Model.

Seismological Research

Letters Volume 89, Issue

2A, Pages 603 – 612, March 2018

The availability of a denser network of seismometers after the earthquakes of Mw 9.1 in 2004 and Mw 8.6 in 2005 supports various seismic studies, one of which regards the precise relocation of the hypocenters. In this study, hypocenter relocation was performed using a teleseismic double-difference (DD) relocation method (teletomoDD) combining arrival times of P and S waves from stations at local, regional, and teleseismic distances.

Relocation results show a reduction in travel-time residuals compared with the initial locations. The relocation results better illuminate subducted slabs and active faults in the region such as the Mentawai back thrust and the outer rise in the subduction zone south of Java. Synthesis of the results provides further insight into seismogenesis in the region.*

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