Source Model for the Tsunami Inside Palu Bay Following the 2018 Palu Earthquake, Indonesia
AuthorsGusman, Aditya Riadi
Nugraha, Andri Dian
Wiyono, Samsul Hadi
Palgunadi, Kadek Hendrawan
Daryono, Mudrik Rahmawan
Embargo End Date2020-02-02
Permanent link to this recordhttp://hdl.handle.net/10754/668753
MetadataShow full item record
AbstractOn 28 September 2018, a strike-slip earthquake occurred in Palu, Indonesia, and was followed by a series of tsunami waves that devastated the coast of Palu Bay. The tsunami was recorded at the Pantoloan tide gauge station with a peak amplitude of ~2 m above the water level and struck at high tide. We use the Pantoloan tsunami waveform and synthetic aperture rada displacement data in a joint inversion to estimate the vertical displacement around the narrow bay. Our inversion result suggests that the middle of the bay was uplifted up to 0.8 m, while the other parts of the bay subsided by up to 1 m. However, this seafloor displacement model alone cannot fully explain the observed tsunami inundation. The observed tsunami inundation heights and extents could be reproduced by a tsunami inundation simulation with a source model that combined the estimated vertical displacement with multiple subaerial-submarine landslides. Plain Language Summary The tsunami that devastated Palu and other coastal towns inside Palu Bay on 28 September 2018 was recorded at a sea level monitoring station in Pantoloan. The recorded tsunami wave data are used in an inversion method to estimate the source of the tsunami in the form of an initial seafloor displacement. We found that the seafloor displacement was the main cause of the large tsunami. Satellite images and field survey data suggest that landslides around multiple river deltas also generated local tsunami waves. Our numerical simulations of the tsunami inundation show that the disaster was caused by a combination of the sudden ground and seafloor changes from the earthquake, landslides, and the high tide at the time of the event.
CitationGusman, A. R., Supendi, P., Nugraha, A. D., Power, W., Latief, H., Sunendar, H., … Daryono, M. R. (2019). Source Model for the Tsunami Inside Palu Bay Following the 2018 Palu Earthquake, Indonesia. Geophysical Research Letters, 46(15), 8721–8730. doi:10.1029/2019gl082717
SponsorsWe thank BMKG for providing the earthquake data catalog used in this study. Tide gauge data at Pantoloan tide gauge station was provided by the Geospatial Information Agency of Indonesia (BIG) http://tides.big.go.id/. The DEMNAS (BIG) topographic data with grid resolution of 0.27 arc sec can be downloaded from http://tides.big.go. id/DEMNAS/. The BATNAS (BIG) bathymetric data with grid resolution of 6 arc sec can be downloaded from http://tides.big.go.id/DEMNAS/. National tsunami and earthquake damage assessment and base map in Palu are available from BIG https:// cloud.big.go.id/. Satellite image data for Palu Bay before and after the earthquake can be downloaded from http:// www.digitalglobe.com/ecosystem/ open-data. The satellite data are distributed under creative commons attribution noncommercial 4.0 data license, in Open Data Program Digital Globe a Maxar Company Indonesia earthquake and tsunami. LiDAR data for Palu city was provided by Australia-Indonesia Facility for Disaster Reduction (AIFDR). Sentinel-1 satellite data are available from Copernicus (https://sci-hub.copernicus.eu/). The aftershock data are from the Agency for Meteorology, Climatology, and Geophysics of Indonesia (BMKG) earthquake catalog. We thank the Editor and two anonymous reviewers for their comments and suggestions to improve this article. This work was supported by public research funding from the Government of New Zealand.
PublisherAmerican Geophysical Union (AGU)
JournalGeophysical Research Letters