Search

The island of Sulawesi, Indonesia, is located in a complex and tectonically active region, and has experienced tsunamis in the past. One of the major earthquake and tsunami events was the 23 February 1969 event that struck the Majene region in western Sulawesi Island. Interpretation of the historical accounts revealed that the Mw 7.0 earthquake generated strong intensity up to VIII on the Modified Mercalli Intensity scale. The earthquake was followed by an unusually high tsunami of 4 m that rapidly decayed within 25 km from the highest observation site. Hypocentre and earthquake mechanism analyses confirmed that it was an inland earthquake with a thrust mechanism. Ground motion modelling is able to reproduce the earthquake intensity but earthquake scenarios are unable to reconstruct the tsunami observations. A plausible solution to explain the tsunami report is from a combined scenario of an earthquake and a submarine mass failure of 0.5 km 3 . [ABSTRACT FROM AUTHOR]

Abstract Eastern Indonesia is one of the world’s most complex regions in terms of tsunami hazards, as it accommodates numerous seismic and non-seismic tsunami sources with a history of deadly tsunamis. This study is an effort to enhance tsunami hazard knowledge in eastern Indonesia where limited data and analyses exist. We provide a brief understanding of eastern Indonesia’s tsunami hazards by modelling selected deterministic tsunami scenarios from tectonic, submarine mass failure (SMF), and volcanic sources. To our knowledge, this is the first time that tsunami hazards modelling from such diverse sources in Indonesia has been performed. Our methodology is a deterministic tsunami hazard analysis considering credible tsunami sources from historical and contemporary data, modelling them using state-of-the-art simulation tools. We modelled two Mw7.8 tsunamigenic earthquake scenarios on the Flores back-arc thrust, one rupturing the basal fault (FBT-BF) and the other rupturing the splay fault (FBT-SF), showing that the two scenarios produce maximum tsunami amplitudes of $$\sim$$ ∼ 5.3 m and $$\sim$$ ∼ 4.2 m, respectively, which are comparable to the deadly 1992 Flores tsunami. We modelled potential SMF-generated tsunamis in the Makassar Strait with SMF volumes of 5 $$\hbox {km}^3$$ km 3 and 225 $$\hbox {km}^3$$ km 3 which yielded maximum tsunami heights of $$\sim$$ ∼ 1.1 m and $$\sim$$ ∼ 4.3 m along the eastern coast of Kalimantan Island and $$\sim$$ ∼ 2.9 m and $$\sim$$ ∼ 11.1 m along the west shore of Sulawesi Island, respectively. The 1871 Ruang volcanic tsunami is studied through existing historical documents and a source model is proposed comprising a flank collapse with volume of $$0.10\ \mathrm{km}^3$$ 0.10 km 3 . Such a source model successfully reproduced the 25 m runup reported in a historical account.

Eastern Indonesia is one of the world's most complex regions in terms of tsunami hazards, as it accommodates numerous seismic and non-seismic tsunami sources with a history of deadly tsunamis. This study is an effort to enhance tsunami hazard knowledge in eastern Indonesia where limited data and analyses exist. We provide a brief understanding of eastern Indonesia's tsunami hazards by modelling selected deterministic tsunami scenarios from tectonic, submarine mass failure (SMF), and volcanic sources. To our knowledge, this is the first time that tsunami hazards modelling from such diverse sources in Indonesia has been performed. Our methodology is a deterministic tsunami hazard analysis considering credible tsunami sources from historical and contemporary data, modelling them using state-of-the-art simulation tools. We modelled two Mw7.8 tsunamigenic earthquake scenarios on the Flores back-arc thrust, one rupturing the basal fault (FBT-BF) and the other rupturing the splay fault (FBT-SF), showing that the two scenarios produce maximum tsunami amplitudes of ∼ 5.3 m and ∼ 4.2 m, respectively, which are comparable to the deadly 1992 Flores tsunami. We modelled potential SMF-generated tsunamis in the Makassar Strait with SMF volumes of 5 km 3 and 225 km 3 which yielded maximum tsunami heights of ∼ 1.1 m and ∼ 4.3 m along the eastern coast of Kalimantan Island and ∼ 2.9 m and ∼ 11.1 m along the west shore of Sulawesi Island, respectively. The 1871 Ruang volcanic tsunami is studied through existing historical documents and a source model is proposed comprising a flank collapse with volume of 0.10 km 3 . Such a source model successfully reproduced the 25 m runup reported in a historical account. [ABSTRACT FROM AUTHOR]