TY - JOUR
T1 - Simulation of the Submarine Landslide Tsunami on 28 September 2018 in Palu Bay, Sulawesi Island, Indonesia, Using a Two-Layer Model
AU - Pakoksung, Kwanchai
AU - Suppasri, Anawat
AU - Imamura, Fumihiko
AU - Athanasius, Cipta
AU - Omang, Amalfi
AU - Muhari, Abdul
N1 - Funding Information:
The observational data and tsunami flow depth data used to verify the tsunami models of the 2018 Palu tsunami were provided by the Center for Volcanology and Geological Hazard Mitigation, Geological Agency of Indonesia. Tidal gauge records at Pantoloan were provided by the Coastal Disaster Mitigation Division, Ministry of Marine Affairs and Fisheries, Jakarta, Indonesia. In this study, the QGIS software was used to illustrate the spatial data. This research was funded by the Willis Research Network (WRN) under the Pan-Asian/Oceanian tsunami risk modeling project through the International Research Institute of Disaster Science (IRIDeS) at Tohoku University.
Publisher Copyright:
© 2019, Springer Nature Switzerland AG.
PY - 2019/8/1
Y1 - 2019/8/1
N2 - The strike-slip earthquake on 28 September 2018 (Mw 7.5) along the Palu-Koro fault on Sulawesi Island has raised concerns about the potential impact of tsunamis generated by submarine landslides in Palu Bay, Indonesia. The horizontal displacement of the Palu-Koro fault generated landslide tsunamis that covered Palu Bay, creating wave-related hazards along the coastal area. Based on the unusual amount of information on this tsunami, this study investigated possible sources using the available preliminary data. The generation of comparatively small tsunamis by coseismic seafloor deformation is omitted, and only tsunamis generated by submarine/subaerial landslides are analyzed in this study. Two-layer modeling (soil and water) based on the shallow-water equation was used to simulate the tsunami propagation in the bay with severe, moderate, and minor impacts. The accuracy of the model was validated based on the waveform at the Pantoloan tidal gauge and trace data. The tsunami heights from a combination of small to large submarine landslides could reach up to 3.0–7.0 m along the Palu shores. This model focused on studying the effects of the tidal level on coastal inundation in Palu Bay, using the 2018 Palu tsunami event as a benchmark scenario, to demonstrate the capabilities of the model. One result shows that, regardless of the tidal level, the 2018 Palu tsunami, which occurred during high tide, will always result in flooding, with a maximum tsunami height of up to 7.0 m above mean sea level. The main results suggest two causes for this tsunami event: the tsunami source and the topography. First, the model requires one large source at the bay entrance to reproduce the arrival time (approximately 5 min) and the large wave observed at the Pantoloan gauge. To reproduce the later waves, small sources in the bay (S1–S6) and minor large sources (L2 and L3) are needed. Second, the datum correction for the terrain is changed to improve the accuracy of the water level. Additionally, the removal of buildings from the topography is important to achieve highly accurate flow depths and to obtain an inundation area close to the real situation. The impacts along the coastline of Palu Bay from peak waves can be used to identify tsunami hazards in the area in the future.
AB - The strike-slip earthquake on 28 September 2018 (Mw 7.5) along the Palu-Koro fault on Sulawesi Island has raised concerns about the potential impact of tsunamis generated by submarine landslides in Palu Bay, Indonesia. The horizontal displacement of the Palu-Koro fault generated landslide tsunamis that covered Palu Bay, creating wave-related hazards along the coastal area. Based on the unusual amount of information on this tsunami, this study investigated possible sources using the available preliminary data. The generation of comparatively small tsunamis by coseismic seafloor deformation is omitted, and only tsunamis generated by submarine/subaerial landslides are analyzed in this study. Two-layer modeling (soil and water) based on the shallow-water equation was used to simulate the tsunami propagation in the bay with severe, moderate, and minor impacts. The accuracy of the model was validated based on the waveform at the Pantoloan tidal gauge and trace data. The tsunami heights from a combination of small to large submarine landslides could reach up to 3.0–7.0 m along the Palu shores. This model focused on studying the effects of the tidal level on coastal inundation in Palu Bay, using the 2018 Palu tsunami event as a benchmark scenario, to demonstrate the capabilities of the model. One result shows that, regardless of the tidal level, the 2018 Palu tsunami, which occurred during high tide, will always result in flooding, with a maximum tsunami height of up to 7.0 m above mean sea level. The main results suggest two causes for this tsunami event: the tsunami source and the topography. First, the model requires one large source at the bay entrance to reproduce the arrival time (approximately 5 min) and the large wave observed at the Pantoloan gauge. To reproduce the later waves, small sources in the bay (S1–S6) and minor large sources (L2 and L3) are needed. Second, the datum correction for the terrain is changed to improve the accuracy of the water level. Additionally, the removal of buildings from the topography is important to achieve highly accurate flow depths and to obtain an inundation area close to the real situation. The impacts along the coastline of Palu Bay from peak waves can be used to identify tsunami hazards in the area in the future.
KW - Palu tsunami
KW - Tsunami
KW - numerical simulation
KW - submarine landslide tsunami
KW - two-layer modeling
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U2 - 10.1007/s00024-019-02235-y
DO - 10.1007/s00024-019-02235-y
M3 - Article
AN - SCOPUS:85067229036
VL - 176
SP - 3323
EP - 3350
JO - Pure and Applied Geophysics
JF - Pure and Applied Geophysics
SN - 0033-4553
IS - 8
ER -