Papers by Galih Adi Prayitno
Lecture notes in civil engineering, 2023
IOP Conference Series: Earth and Environmental Science
A magnitude (Mw) 7.5 Palu-Donggala earthquake struck Palu, Indonesia on Friday, 28 September 2018... more A magnitude (Mw) 7.5 Palu-Donggala earthquake struck Palu, Indonesia on Friday, 28 September 2018 at 18:02:44 Central Indonesia Time (GMT+8). The earthquake resulted in tsunami and flowslide liquefaction. Balaroa, Petobo, Jono Oge and South Sibalaya were affected areas of flowslide liquefaction. Area of Petobo flowslide liquefaction had the largest impact as compared to other locations. This paper emphasizes on the observations on the ground surface when liquefaction occurred in Petobo. Interviews with the survivors and living witnesses, displacement vectors with reference to buildings, observations of soil conditions and groundwater levels as well as descriptions of conditions pre- and post-slide, are conducted in these observations. In addition, several data consisting of Satellite Imagery, DEM (Digital Elevation Model), regional geology and some photographs taken at the site are also discussed. Results show the slope of the area of flowslide liquefaction ranges from 1° to 2°. Bes...
Landslides, 2021
The Palu-Donggala earthquake struck Palu city of Sulawesi island, Indonesia, on 28 September 2018... more The Palu-Donggala earthquake struck Palu city of Sulawesi island, Indonesia, on 28 September 2018. A large-scale liquefaction phenomena occurred in some areas which caused massive fatalities and destructions. The most severe liquefaction incident during the earthquake followed by flowslides occurred in Petobo district of the city. The affected area due to Petobo flowslide liquefaction was approximately 1.64 km2. The damages were severe because of densely populated area with estimated more than 3300 houses collapsed and nearly 2000 fatalities. The slide materials transformed into debris and flowed on the low-relief ground of about 2% with a slide distance of more than 800 m. A site reconnaissance of Petobo flowslide was conducted in early 2020, which covered surface observations and documentations before and after the flowslide, interpretations of geological characteristics, summary of witness interviews, analyses of ground displacement and changes in surface elevation and slope due to the flowslide. The results reveal insights as to the failure mechanism of the Petobo flowslide. Based on the observed phenomena on the surface, the Petobo flowslide area could generally be divided into four types of morphology, namely, ground slide (GS), liquefaction spread (LS), liquefaction flow (LF) and debris flood (DF). The GS and LS were considered to be the initiation zones, then the slide materials spread down and formed LF zone. In this area, the soils became wet and muddy as triggered by liquefaction. The liquefied materials then transported into DF zone where densely populated areas in lower elevation of the site were hit.
Sustainability
This paper presents the results of the subsurface investigation and liquefaction assessment of th... more This paper presents the results of the subsurface investigation and liquefaction assessment of the Petobo flowslide, induced by soil liquefaction during the Mw 7.5 Palu–Donggala earthquake of Indonesia on 28 September 2018. The investigations, including drilling, standard penetration tests, electrical resistivity imaging survey, dynamic probing, groundwater table monitoring, etc., were conducted along the main road that passes through the middle of the flowslide area. Liquefaction assessments and flowslide simulations were carried out with three assumed scenarios. Scenario 1 describes the condition if the flowslide were to be retriggered at the cease of sliding due to the same earthquake striking the site. Scenarios 2 and 3 attempt to examine the influence of locally raised groundwater levels due to the infiltration of the Gumbasa irrigation system and widespread paddy fields of the site as a result of soil liquefaction and the flowslide. Subsurface investigations revealed that, wit...
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Papers by Galih Adi Prayitno