Reconnaissance on Liquefaction-induced Flow Failure Caused by the 2018 Mw 7.5 Sulawesi Earthquake, Palu, Indonesia
Keywords:confined aquifer, gently sloping ground, liquefaction damage, lateral spreading, landslide, site reconnaissance
The Mw 7.5 Sulawesi Earthquake 2018 was a catastrophic disaster that resulted in large numbers of casualties. This study aimed to investigate the damages of liquefaction-induced-flow failure in three areas in Palu city, i.e. Petobo, Balaroa, and Jono Oge. It was found that this flow failure occurred on a large scale at a very gentle ground inclination, ranging from 1 to 3%. In order to gain an understanding of the soil conditions in these specific locations, Portable Dynamic Cone Penetration Tests were conducted in Petobo. The results showed that the soil layers in the affected area were in a loose state compared to the non-affected areas. Furthermore, some spots of freshwater inundation were recognized in Petobo and Balaroa, even two weeks after the disaster. Based on this evidence, a mechanism of liquefaction-induced-flow failure caused by a confined aquifer is proposed.
The United States Geological Survey, Earthquake Hazards Program, The United States Geological Survey, https://earthquake.usgs.gov/earthquakes /eventpage/us1000h3p4/executive, (October 28th, 2018).
The National Agency of Disaster Management, 2018 Sulawesi Earthquake in Central Sulawesi, The National Agency of Disaster Management, https://bnpb.go.id/geoportal.html, (November 13th, 2018).
Bao, H., Ampuero, J. & Meng, L., Early and Persistent Supershear Rupture of the 2018 Magnitude 7.5 Palu Earthquake, Nat. Geosci., 12, pp. 200-205, 2019.
Socquet, A., Hollingsworth, J., Pathier, E., Evidence of Supershear during the 2018 Magnitude 7.5 Palu Earthquake from Space Geodesy, Nat. Geosci., 12, pp. 192-199, 2019.
Indonesian Society for Geotechnical Engineering, The National Research for Earthquake, & Ministry of Public Works, Damages Associated with Geotechnical Problems in 2018 Palu Earthquake Indonesia, The National Research Centre for Earthquake, Jakarta, 2018.
Kadarusman, A., Leeuwen, T. van, & Sopaheluwakan, J., Eclogite, Peridotite, Granulite, and Associated High-Grade Rocks from The Palu Region, Central Sulawesi, Indonesia: An Example of Mantle and Crust Interaction in A Young Orogenic Belt, in Proceedings JCM Makassar, 2011.
Bellier, O., Sebrier, M., Beaudouin, T., Villeneuve, M., Braucher, R., Bourles, D., Siame, L., Putranto, E. & Pratomo, I., High Slip Rate for a Low Seismicity along the Palu-Koro Active Fault in Central Sulawesi (Indonesia), Terra Nova, 13(6), pp. 463-470, 2001.
Watkinson, M.I., Ductile Flow in the Metamorphic Rocks of Central Sulawesi, The SE Asian Gateway: History and Tectonics of the Australia-Asia Collision, 355, pp. 157-176, 2011.
Thein, P.S., Pramumijoyo, S., Brotopuspito, K.S., Kiyono, J., Wilopo, W., Furukawa, A. & Setianto, A., Estimation of Seismic Ground Motion and Shaking Parameters Based on Microtremor Measurements at Palu City, Central Sulawesi Province, Indonesia, World Academy of Science, Engineering and Technology, International Journal of Geological and Environmental Engineering, 8(5), pp. 308-319, 2014.
Zeffitni, Groundwater Potency in Palu Groundwater Basin Based on Hidromorfology and Hydrogeology Approachment (in Bahasa Indonesia), Jurnal Geografi, 11(22), pp. 97-106, 2013.
Youd, T.L., Liquefaction, Flow, and Associated Ground Failure, U.S. Geological Survey, Virginia, 1973.
Takase, M. & Sasada, M., The Application of Portable Dynamic Cone Penetration Test to the Geo-Disaster Reconnaissance (in Japanese), Japan Geotechnical Consultants Association Technical Forum 2013 in Nagano, pp. 64-65, 2013.
Bradley, K., Mallick, R. & Andikagumi, H., Earthquake-triggered 2018 Palu Valley Landslides Enabled by Wet Rice Cultivation, Nat. Geosci., 12, pp. 932-939, 2019.