Tsunami potential in the Makran subduction zone: Amplification effects from earthquake rupture directivity and speed

Abstract

The Makran subduction zone has historically experienced major earthquakes and tsunamis. Here, we integrate fault morphology, InSAR measurements, and high-resolution bathymetry to quantitively evaluate potential future tsunami sources and tsunami wave characteristics. We systematically investigate how earthquake rupture speed and direction could affect tsunami hazards for the Makran region. Our analyses reveal the following new understanding: (1) The estimated maximum slip deficit in the Makran region southeast of the Gwadar port is >4 m since the last significant 1851 rupture; (2) Earthquakes with finite rupture speed investigated in the range of 300–1,000 m/s are calculated to generate higher tsunami waves than the static rupture model; (3) For an east-to-west rupture direction, the tsunami waves are calculated to arrive at the Gwadar port 3–5 mins later but with higher waves than the static rupture model. Together, our results highlight the importance of the source earthquake rupture speed and directivity in controlling tsunamigenic effects.