Evaluation of tsunami wave energy generated by earthquakes in the Makran subduction zone

TL;DR

This study uses numerical simulations to evaluate tsunami wave energy generated by earthquakes in the Makran subduction zone, revealing that tsunami energy is a small fraction of seismic energy but increases significantly with earthquake magnitude.

Contribution

It provides a detailed numerical analysis of tsunami wave energy in the Makran zone, highlighting the relationship between earthquake magnitude and tsunami energy.

Findings

Tsunami wave energy is only 0.33% of seismic energy.

Tsunami energy increases about 1000 times with each unit increase in magnitude.

The study models the entire Makran subduction zone with 20 segments.

Abstract

The Makran subduction zone, an approximate 1000 km section of the Eurasian-Arabian plate, is located offshore of Southern Iran and Pakistan. In 1945, the Makran subduction zone (MSZ) generated a tsunamigenic earthquake with a magnitude of Mw 8.1. The region has also experienced large historical earthquakes but the data regarding these events are poorly documented. Therefore, the need to investigate tsunamis in Makran must be taken into serious consideration. Using hydrodynamic numerical simulation, we evaluate the tsunami wave energy generated by bottom motion for a tsunamigenic source model distributed along the full length of the Makran subduction zone. The whole rupture of the plate boundary is divided into 20 segments with width of order of 200 km and a co-seismic slip of 10 m but with various lengths. Exchanges between kinetic and potential components of tsunami wave energy are shown. The total tsunami wave energy displays only 0.33% of the seismic energy released from the earthquake source. As a result, for every increase in magnitude by one unit, the associated tsunami wave energy becomes about 10^3 times greater.