The Sibalaya flowslide initiated by the 28 September 2018 MW 7.5 Palu-Donggala, Indonesia earthquake

Aaron P. Gallant, Jack Montgomery, H. Benjamin Mason, Daniel Hutabarat, A. Nicole Reed, Joseph Wartman, Masyhur Irsyam, Pintor T. Simatupang, Idrus M. Alatas, Widjojo A. Prakoso, Didiek Djarwadi, Rahma Hanifa, Paulus Rahardjo, Lutfi Faizal, Dandung S. Harnanto, Aksan Kawanda, Agus Himawan, Widodo Yasin

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


The 28 September 2018 MW 7.5 Palu-Donggala earthquake caused massive flowslides within and nearby the city of Palu. We performed post-earthquake reconnaissance at the flowslide sites and examine a large flowslide that occurred approximately 30 km south of Palu in Sibalaya. We performed field mapping, unmanned aerial vehicle flights, and eyewitness interviews. After the post-earthquake reconnaissance, we performed cone penetration tests. We developed hypothesized flowslide initiation and progression mechanisms from our collective reconnaissance efforts. Based on observed morphological features and eyewitness accounts, the flowslide initiated near a change from steep to shallow terrain. Significant liquefaction of the underlying soils initiated the flowslide after strong ground motions ceased. We speculate progressive liquefaction and/or void redistribution contributed to the timing and delay of initiation.

Original languageEnglish
Pages (from-to)1925-1934
Number of pages10
Issue number8
Publication statusPublished - 1 Aug 2020


  • Flowslide
  • Liquefaction
  • Palu-Donggala earthquake


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