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Coastal landslides in Palu Bay during 2018 Sulawesi earthquake and tsunami


In this paper, we investigate the sources for Palu Bay tsunamis, which occurred in September 2018 after a Mw 7.5 earthquake struck on a strike-slip fault. Previous land-based field studies have identified numerous coastal landslides as possible sources for tsunami generation. Here, we present new post-earthquake bathymetry survey data in the bay. We compare the new very detailed nearshore bathymetry with the pre-earthquake data so as to quantify the magnitudes and configurations of coastal landslides and the characteristics of landslide-generated waves. We perform numerical simulations of tsunami propagation, isolating the coastal landslides as the only sources. The results show that, although the landslide-generated waves characteristically have shorter periods than the observed tsunami waves, the combination of the waves is able to produce long waves comparable with those observed, due to the ringing effects of the trapped waves inside the bay. Therefore, we conclude that landslide-generated waves played a significant role in the tsunamis in Palu Bay. Nevertheless, it is likely that the tsunamis were caused by a combination of tectonic and landslide sources.

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Data availability

BIG bathymetry data is publicly available on the internet (National Mapping Agency of Indonesia 2019). The datasets generated and analyzed in the current study are available from the corresponding authors on reasonable request.


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We would like to thank the Marine Research Centre of the Ministry of Marine Affairs and Fisheries of Indonesia (MMAF) Indonesia, the Indonesian Tsunami Society (IATsI), and the Ministry of Research, Technology and Higher Education of Indonesia (MORTHE) for making the nearshore survey possible. We also would like to acknowledge the cooperation with the Hydrography and Oceanography Center (PUSHIDROSAL) of the Indonesian Navy and its head, Rear Admiral Harjo Susmoro, for sharing the deep water survey data. Supports from Bpk. Abdul Rasyid from the Fisheries Port of Donggala, Capt. Oke Dwiyana P from PUSHIDROSAL, Dr. Widjo Kongko from BPPT, Mr. Ardito Kodijat from IOTIC IOC/UNESCO, and Dr. Rahman Hidayat from the Coordinating Ministry of Maritime Affairs of Indonesia (Kemenkomaritim) are also highly appreciated. We would like to thank PT. GEOTINDO, Mr. Ignacio Barranco, Dr. Kuifeng Zhao, and the crew of fishermen from boat PACEKO for the acquisition of the data in the field. We would also like to thank Dr. Hong-Yueh Lo for valuable discussions about his landslide-induced wave generation model and Dr. Ignacio Sepúlveda and Mr. Yu-Lin Tsai for their support with the COMCOT model. This paper contains satellite imagery from Google Earth, Digital Globe open data for disaster response, and Sentinel-2 cloudless data ( by EOX IT Services GmbH; containing modified Copernicus Sentinel data 2017 and 2018).


The authors acknowledge internal funding from the National University of Singapore.

Author information




P.L.-F. Liu acquired the funding and coordinated the project. P.L.-F. Liu, P. Higuera, S. Husrin, and G.S. Prasetya conceptualized the work. P. Higuera, J. Prihantono, H. Diastomo, and D.G. Pryambodo performed the field survey and carried out the raw data analysis. H. Susmoro provided the deep water survey data. P. Higuera performed the data analysis and simulations and prepared the visualizations. P.L.-F. Liu and P. Higuera prepared the original draft. All authors contributed to reviewing and editing the final paper.

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Correspondence to P. L.-F. Liu or P. Higuera.

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The authors declare that they have no competing interests.

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Liu, P.LF., Higuera, P., Husrin, S. et al. Coastal landslides in Palu Bay during 2018 Sulawesi earthquake and tsunami. Landslides 17, 2085–2098 (2020).

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  • Palu earthquake
  • Palu tsunami
  • Coastal landslides
  • Bathymetry
  • Survey