Numerical modeling of the subaerial landslide source of the 22 December 2018 Anak Krakatoa volcanic tsunami, Indonesia

Mohammad Heidarzadeh, Takeo Ishibe, Osamu Sandanbata, Abdul Muhari, Antonius B. Wijanarto

Research output: Contribution to journalArticlepeer-review

106 Citations (SciVal)

Abstract

The eruption of the Anak Krakatoa volcano (Indonesia) in December 2018 produced a destructive tsunami with maximum runup of 13 m killing 437 people. Since the occurrence of this rare tsunami, it has been a challenge as how to model this tsunami and to reconstruct the network of coastal observations. Here, we apply a combination of qualitative physical modeling and wavelet analyses of the tsunami as well as numerical modeling to propose a source model. Physical modeling of a volcano flank collapse showed that the initial tsunami wave mostly involves a pure-elevation wave. We identified initial tsunami period of 6.3–8.9 min through Wavelet analysis, leading to an initial tsunami dimension of 1.8–7.4 km. Twelve source models were numerically modelled with source dimensions of 1.5–4 km and initial tsunami amplitudes of 10–200 m. Based on the qualities of spectral and amplitude fits between observations and simulations, we constrained the tsunami source dimension and initial amplitude in the ranges of 1.5–2.5 km and 100–150 m, respectively. Our best source model involves potential energy of 7.14 × 1013–1.05 × 1014 J equivalent to an earthquake of magnitude 6.0–6.1. The amplitude of the final source model is consistent with the predictions obtained from published empirical equations.

Original languageEnglish
Article number106733
JournalOcean Engineering
Volume195
DOIs
Publication statusPublished - 1 Jan 2020

Bibliographical note

Funding Information:
Agency for Geo-spatial Information (BIG), Indonesia ( http://tides.big.go.id ) supplied the tide gauge records used in this study. We sincerely thank scientists in BIG including Andi Eka Sakya, Hasanuddin Z Abidin and Mohamaad Arief Syafi'i for their efforts to provide the data in a timely manner. We are grateful to HyeJeong Kim, Taku Ueda, Naoto Yokotani (all from University of Tokyo, Japan) for helping us to perform the physical modeling part of this study. The GMT mapping tool by Wessel and Smith (1998) were used to draft figures. The article benefited from constructive review comments from two anonymous reviewers. MH was funded by the Royal Society grant number CHL\R1\180173 and the Great Britain Sasakawa Foundation grant number 5542 (2018/19) .

Publisher Copyright:
© 2019 The Authors

Keywords

  • Anak Krakatoa
  • Indonesia
  • Numerical simulations
  • Sunda Strait
  • Volcanic tsunami
  • Wavelet

ASJC Scopus subject areas

  • Environmental Engineering
  • Ocean Engineering

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