Field Survey of the 2018 Sulawesi Tsunami Deposits
On 28 September 2018, a Mw 7.5 earthquake struck Sulawesi Island, soon followed by a destructive tsunami. This study provides a case history of tsunami deposition where submarine landslides or coastal collapses have contributed to and intensified tsunami generation. The sedimentary features resulting from this complex tsunami mechanism are not yet well understood. We surveyed tsunami deposits at six locations along the coastline of Palu Bay, in addition to measuring tsunami flow depth, run-up height, and inundation distance at each site. In general, the tsunami height was less than 8 m with a maximum inundation distance of 310 m. The tsunami deposits are thin with simple sedimentary structures such as fining upward sequences. These sedimentary characteristics are typical of tsunami deposits elsewhere around the world. This work is a preliminary study, in that numerical modeling including sediment transport has not been performed. Further work is needed to distinguish tsunamis with different source mechanisms.
KeywordsTsunami generated from landslide tsunami deposit field survey Palu—Sulawesi 2018
The authors would like to express their gratitude to the Coordinating Ministry for Marine Affairs of the Republic of Indonesia (Kemenkomar RI) for funding the field survey. The field survey was part of Operasi Bakti Teknologi 2018. Dr. Udrekh, the field survey coordinator, is thanked for his full support. Yudhicara (VSI), Prihartanto and Budi (BPPT), Bayu, Gilang, Rahmad, and Rizky (Geological Engineering, Tadulako University) are thanked for help during the field survey. Jonathan Griffin (Geoscience Australia) is thanked for commenting and proofreading of this manuscript.
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