EGU21-4582, updated on 07 Jan 2024
EGU General Assembly 2021
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

Source reconstruction of the 1969 Sulawesi, Indonesia earthquake and tsunami

Ignatius Ryan Pranantyo1, Athanasius Cipta2, Hasbi Shiddiqi3, and Mohammad Heidarzadeh1
Ignatius Ryan Pranantyo et al.
  • 1Department of Civil and Environmental Engineering, Brunel University London, Uxbridge, United Kingdom
  • 2Geological Agency, Bandung, Indonesia
  • 3Department of Earth Science, University of Bergen, Bergen, Norway

An M7.0 earthquake followed by moderate tsunami destructed Majene region, western Sulawesi on 23 February 1969. This event claimed at least 64 lives and caused severe damage to infrastructure. In this study, we reconstructed the earthquake and tsunami source of this event by optimising macroseismic and tsunami dataset reported as well as analysed the earthquake focal mechanism. We estimated that the maximum intensity of the earthquake was VIII (in Modified Mercalli Intensity). From the first motion polarity analysis, the earthquake had a thrust mechanism which was plausibly from the Makassar Thrust. Further, deterministic ground motion modelling successfully fits the intensity data. However, thrust earthquake from the Makassar Thrust was unable to reconstruct 4 m tsunami height observed at Pelattoang. The estimated ratio between maximum tsunami run-up height and lateral distribution distance (I2) from the dataset indicates that the tsunami was generated by a local coastal landslide.

(This study is funded by the Royal Society (UK) grant number CHL/R1/180173)

How to cite: Pranantyo, I. R., Cipta, A., Shiddiqi, H., and Heidarzadeh, M.: Source reconstruction of the 1969 Sulawesi, Indonesia earthquake and tsunami, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4582,, 2021.

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