[S-IT26] New perspectives on the geodynamics of East Asia

[SIT26-P03] Characterize coseismic deformation of Mw 7.5 Palu earthquake in a triple junction in Sulawesi, Indonesia

*MIN-CHIEN TSAI¹、Ying-Hui Yang²、Chun-Ying Chiu³、Jyr-Ching Hu³ (1.Seismological center, Central Weather Bureau, Taipei, Taiwan, R.O.C.、2.School of Civil Engineering and Architecture, Southwest Petroleum University, Chengdu, China、3.Department of Geosciences, National Taiwan University, Taipei, Taiwan, R.O.C.)

キーワード：InSAR , pixel offset , Palu earthquake, Triple junction

We first use SAR satellite data to map the coseismic deformation for the 2018 Mw=7.5 strike-slip earthquake of 28 September 2018 in Palu, Sulawesi, Indonesia. The seismogenic fault is a left-lateral a strike-slip event along the Palu-Koro fault at shallow depth that occurred within the interior of the Molucca Sea microplate, which is part of the Sunda plate. We use D-InSAR technique with ALOS-2 descending orbit radar images to characterize coseismic and deformation pattern induced by Palu earthquake.We also plan to use with sub-pixel correlation form Sentinel-2 and Planet imagery to map the surface rupture area and the coseismic offsets in order to provide the near-field deformation data located in decorrelation zone from the D-InSAR result. Thus we can inverse the distribution of slip on the fault patches. In addition, we also calculate the Coulomb stress transfer for assessing the stress increasing and shadow on the major fault systems, such as the active Poso Fault Zone and Mamuju – Lariang Active Fault Zone. In particular, we will assess the seismic potential by Coulomb stress transfer in Minahasa Active Subduction Zone together with two events with Mw 7.9 and Mw 7.0 happened on 1996/01/01 and 1996/07/22. We try to assess the seismogenic potential in terms of interseismic slip rate, slip rate deficit and coupling ratio for the Palu-Koro fault system in a triple junction of the Sulawesi island.