A combined earthquake-landslide source model for the tsunami from the 27 november 1945 Mw 8.1 makran earthquake

Mohammad Heidarzadeh, Kenji Satake

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40 Citations (SciVal)

Abstract

The tsunami of 27 November 1945 from an Mw 8.1 earthquake in the Makran subduction zone is the only instrumentally recorded and deadly tsunami in the northwest Indian Ocean; offshore Iran, Pakistan, Oman, and India. Despite the fact that some source models have been proposed based on seismic or far-field tsunami data, none of them was able to reproduce one important observation: near-field runup of 10-12 m. Here, we applied numerical modeling and examined three possible secondary sources: (1) splay faulting, (2) delayed rupture of the earthquake source, and (3) submarine landslides. These secondary sources were added to the existing state-of-the-art earthquake source for this tsunami. Results of simulations revealed that only a submarine landslidewith dimensions of 15 km (length) × 15 km (width), a thickness of 600 m, a volume of ~40 km3, and located at 63.0° E, 24.8° N is capable of reproducing the near-field tsunami observation. Such a combined earthquake-landslide source is consistent with all available observations including far-field tsunami waveforms in Karachi (Pakistan) and Mumbai (India), with near-field runup height of 10-12 m, coastal coseismic deformation data in Pasni (subsidence) and Ormara (uplift ~1-3 m), and earthquake magnitude (M 8.0-8.3).

Original languageEnglish
Pages (from-to)1033-1040
Number of pages8
JournalBulletin of the Seismological Society of America (BSSA)
Volume107
Issue number2
DOIs
Publication statusPublished - 30 Apr 2017

Bibliographical note

Funding Information:
Most of the figures were drafted using the Generic Mapping Tool (GMT) software (Wessel and Smith, 1998). We thank Takeo Ishibe (Association for the Development of Earthquake Prediction, Tokyo, Japan) and Tomoya Harada (Earthquake Research Institute [ERI], University of Tokyo) for their assistance in seismicity analysis of the Makran subduction zone.We are grateful to Associate Editor Mark W. Stirling and two anonymous reviewers for their constructive review comments.

Publisher Copyright:
© 2017, Seismological Society of America. All rights reserved.

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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