Tsunami modeling in the Chabahar Bay-Iran from worst-case Makran seismic scenarios: new insights into spectral characterization, separation of the continental shelf, and topography effects

Abstract

The main objectives of this study are evaluating the statistical and spectral properties of tsunami waves as well as their energy behavior associated with the worst-case Makran seismic scenarios. The role of the Oman continental shelf in the tsunami wave propagation also investigated. In this study, the hybrid numerical model, GEOWAVE, is implemented for the entire life of the tsunami, including wave generation, propagation, and inundation. To study the statistical and frequency characteristics of the two worst-case tsunami waves (Mw 9.1 and 8.3), 36 artificial gage stations considered. The ports of Konarak, Sepah, Shahid Beheshti, Shahid Kalantari, and the Iran Bandar port were selected to analyze the frequency behavior of waves inside the ports. Based on spectral analysis of different stations in the Chabahar Bay, a two-period range of 15–25 min and 50–58 min for the Mw 9.1 are dominant. For the Mw 8.3, the maximum two dominant period ranges are 8–16 and 20–32 min. The wavelet analysis for Mw 9.1 indicates that for stations 1 to 30, the tsunami energy spread for the first 2 h after the tsunami arrived at these stations in a relatively wide range of 15–58 min, and then limited within the slightly narrower range. For Mw 8.3, the period range of 25–54 min for the first 4 h is dominant and then focuses on a smaller scope. Frequency-time graphs show that the energy of a tsunami can move between different period intervals at different times.