Characteristics of building fragility curves for seismic and non-seismic tsunamis: case studies of the 2018 Sunda Strait, 2018 Sulawesi-Palu and 2004 Indian Ocean tsunamis

Abstract

Abstract. Indonesia has experienced several recent tsunamis triggered by seismic as well as non-seismic (i.e., landslides) sources. These events damaged or destroyed coastal buildings and infrastructure, and caused considerable loss of life. The impact of tsunami characteristics on structural components can be represented by fragility curves. These cumulative distribution functions express the likelihood of a structure reaching or exceeding a damage state in response to a tsunami hazard intensity measure. Using numerical simulations and post-tsunami observations, we successfully reproduce the hydrodynamic features of the 2018 Sunda Strait and 2018 Sulawesi-Palu tsunamis for the first time. We then compare non-seismic building fragility curves from these events with the ones of the 2004 Indian Ocean tsunami (IOT) to provide a novel understanding of wave period, ground shaking and liquefaction impacts on the structural performance of buildings. Below 5-m flow depth, the 2004 IOT in Khao Lak/Phuket (Thailand), characterized by long wave period due to its seismic source, induces larger damage to buildings than the 2018 Sunda Strait tsunami, triggered by a landslide. We also note that for 4-m flow depth, the building damage probability is almost twice less in Khao Lak/Phuket than in Banda Aceh, where ground motion has been reported before the tsunami arrival. In addition, liquefaction events can cause significant building damage as in Palu, where constructions have been considerably affected by this phenomenon due to the 2018 Sulawesi earthquake. Below 2-m flow depth, the damage probability is greater in Palu than in the Sunda Strait but also in Banda Aceh, although this city has been affected by ground shaking, and then struck by the longer wave period of the IOT.

Mekanika Perambatan Gelombang Tsunami: Studi Kasus Tsunami Teluk Palu Dan Selat Sunda Tahun 2018

“…Tsunami Teluk Palu tanggal 28 September 2018 dipicu oleh gempa tektonik destruktif yang terekam pada jam 10:02 UTC (17:02 WIB) berkekuatan 𝑀 w 7,5 dan berpusat di Kabupaten Donggala, sekitar 77 km arah utara dari Kota Palu, Sulawesi Tengah (Patton et al, 2019;Lahcene et al, 2021). Gelombang tsunami menerjang daratan sepanjang wilayah Teluk Palu disertai dengan bencana likuefaksi.…”