The Central Sulawesi, Indonesia Earthquake and Tsunami of 28th September 2018 – A Field Report by EEFIT-TDMRC 01/11/2019 The Central Sulawesi, Indonesia Earthquake and Tsunami of 28th September 2018 – A Field Report by EEFIT-TDMRC Prof Tiziana Rossetto, EPICentre, University College London Prof Alison Raby, Plymouth University Dr Andrew Brennan, University of Dundee Richard Lagesse, Ove Arup & Partners Singapore Ltd Dr David Robinson, University College London – CEGE EPICentre Rohit Kumar Adhikari, University College London – CEGE EPICentre Muhammad Rezki-Hr, Newcastle University Dr Ella Meilianda, TDMRC, Syiah Kuala University Dr Yunita Idris, TDMRC, Syiah Kuala University Ibnu Rusydy, TDMRC, Syiah Kuala University Intan Dewi Kumala, TDMRC, Syiah Kuala University Report reviewed by Matthew Free, Ove Arup & Partners, London, UK Antonios Pomonis, RMS Joshua Macabuag, World Bank Date 1st November 2019 The Central Sulawesi, Indonesia Earthquake and Tsunami of 28th September 2018 A Field Report by EEFIT-TDMRC 2 Table of Contents Table of Contents .............................................................................................................................. 3 List of Figures ................................................................................................................................... 5 List of Tables .................................................................................................................................. 12 1.0 Introduction ............................................................................................................................... 13 1.1 Reconnaissance Mission Objectives ....................................................................................... 13 1.2 The EEFIT-TDMRC Team .................................................................................................... 14 1.3 Itinerary ................................................................................................................................. 15 2.0 The 2018 Central Sulawesi Earthquake and Tsunami (Lagesse, R.) ............................................ 17 2.1 Geological and Tectonic Setting ............................................................................................. 17 2.2 Seismicity and Seismotectonics .............................................................................................. 20 th 2.3 Overview of the 28 September 2018 Sulawesi Event ............................................................ 24 3.0 Fault Surface Rupture Investigation (Lagesse, R., Brennan, A.; Rusydy, I.) ................................ 26 4.0 Landslide Investigation (Lagesse, R., Brennan, A.; Rusydy, I.) .................................................. 32 4.1 Balaroa .................................................................................................................................. 32 4.2 Petobo ................................................................................................................................... 34 4.3 Jono Oge ............................................................................................................................... 40 4.4 Summary ............................................................................................................................... 41 5.0 Liquefaction and Ground Subsidence Investigation (Brennan, A.; Lagesse, R.; Rusydy, I.) ........ 43 5.1 Local Liquefaction ................................................................................................................. 43 5.1.1 Palu City ......................................................................................................................... 44 5.1.2 Sigi ................................................................................................................................. 49 5.1.3 Donggala Dolphin Park ................................................................................................... 53 5.2 Seafront Loss Due to Liquefaction ......................................................................................... 55 5.2.1 Loli Tasiburi ................................................................................................................... 55 5.2.2 Donggala Town............................................................................................................... 57 5.2.3 Lero ................................................................................................................................ 58 5.3 Summary ............................................................................................................................... 61 6.0 Tsunami Investigation (Raby, A.; Robinson, D.; Rossetto, T.) .................................................... 62 6.1 Tsunami terminology ............................................................................................................. 62 6.2 Past tsunami in the Palu Bay area ........................................................................................... 62 6.2 The 28th September 2018 Tsunami and its characteristics ...................................................... 64 6.2.1 Cause of tsunami in Palu Bay .......................................................................................... 64 6.2.2 International tsunami surveys .......................................................................................... 64 6.2.3 Tsunami characteristics ................................................................................................... 66 The Central Sulawesi, Indonesia Earthquake and Tsunami of 28th September 2018 A Field Report by EEFIT-TDMRC 3 6.3 General tsunami observations obtained through interviews and video footage by TDMRC-EEFIT Team ........................................................................................................................................... 69 6.3.1 General tsunami observations from Wani ........................................................................ 70 6.3.2 General tsunami observations from Kampung Muara near Tasiburi ................................. 72 6.3.3 General tsunami observations from Mamboro ................................................................. 74 6.4 Tsunami Inundation Observations .......................................................................................... 75 6.4.1 Tsunami inundation inland .............................................................................................. 75 6.4.2. Tsunami inundation along Palu river .............................................................................. 78 6.4.3 Sheltering effects ............................................................................................................ 79 6.5 Tsunami warning and evacuation ........................................................................................... 81 6.6 Summary ............................................................................................................................... 83 7.0 Observation of Impact on Buildings and Infrastructure (Rossetto, T.; Adhikari, R.; Idriss, Y.; Raby, A).................................................................................................................................................... 84 7.1 Damage Scale and Survey Sheet ............................................................................................ 84 7.2 Observations on the characteristics and performance of typical low-rise houses ...................... 89 7.2.1 Timber “stilt” houses ....................................................................................................... 89 7.2.2 Timber frame houses with infills ..................................................................................... 90 7.2.3 Confined masonry housing .............................................................................................. 92 7.2.4 Guidance for low-rise housing construction in seismic areas in Indonesia ........................ 93 7.3 Observations on the performance of educational facilities ...................................................... 97 7.3.1 Tadulako University Campus .......................................................................................... 97 7.3.2 Schools ......................................................................................................................... 100 7.4 Healthcare Facilities ............................................................................................................ 111 7.4.1 Tadulako University Hospital ........................................................................................ 111 7.4.2 Anutapura Hospital ....................................................................................................... 113 7.5 Hotel Buildings .................................................................................................................... 114 7.5.1 Grand Duta Hotel .......................................................................................................... 115 7.5.2 Mercure Hotel ............................................................................................................... 117 7.5.3 Swiss Belhotel .............................................................................................................. 119 7.6 Palu Airport ......................................................................................................................... 120 7.7 Ponulele Bridge ..................................................................................................................