Preliminary estimation of the tsunami hazards associated with the Makran subduction zone at the northwestern Indian Ocean

Abstract

We present a preliminary estimation of tsunami hazard associated with the Makran subduction zone (MSZ) at the northwestern Indian Ocean. Makran is one of the two main tsunamigenic zones in the Indian Ocean, which has produced some tsunamis in the past. Northwestern Indian Ocean remains one of the least studied regions in the world in terms of tsunami hazard assessment. Hence, a scenario-based method is employed to provide an estimation of tsunami hazard in this region for the first time. The numerical modeling of tsunami is verified using historical observations of the 1945 Makran tsunami. Then, a number of tsunamis each resulting from a 1945-type earthquake (M w 8.1) and spaced evenly along the MSZ are simulated. The results indicate that by moving a 1945-type earthquake along the MSZ, the southern coasts of Iran and Pakistan will experience the largest waves with heights of between 5 and 7 m, depending on the location of the source. The tsunami will reach a height of about 5 m and 2 m in northern coast of Oman and eastern coast of the United Arab Emirates, respectively.

The Balochistan Earthquake 2013: Emergence of a New Island in the Arabian Sea

“…Several researchers assessed the tsunami hazard along the coast of Iran, Pakistan and Oman originating from the subduction process [11][12][13]. Heidarzadeh and his colleagues [14,15] [18][19][20][21]. These motions typically result in northsouth to northeast-southwest strike-slip motion at the latitude of the September 24 earthquake that is primarily accommodated on the Chaman Fault, with the earthquake potentially occurring on one of the southern-most strands of this fault system [5].…”

An assessment of the tsunami risk in Muscat and Salalah, Oman, based on estimations of probable maximum loss

“…The Makran subduction zone has one of the world's largest accretionary wedges (Heidarzadeh et al, 2008), characterized by a high sediment thickness of 7km (Koppa et al, 2000in Heidarzadeh et al, 2008. It is the unconsolidated and semiconsolidated sediments, which make up around 70 km of the seaward forearc (Byrne and Sykes, 1992), which have the potential to fail and produce large submarine tsunamigenic landslides.…”

“…In such circumstances a deterministic tsunami hazard assessment (DTHA) can be carried out to model the effects of a worst-case scenario (Geist and Parsons, 2006;Okal et al, 2006). Tsunami generation in the Arabian Sea has been modelled before but not specifically for the purpose of a tsunami hazard risk assessment and particularly for the coasts of Oman (Heidarzadeh et al, 2007;Heidarzadeh and Kijko, 2011;Heidarzadeh and Satake, 2014). Heidarzadeh et al (2007) modelled the effects of a range of tsunami events off the southern coast of Iran using deformation algorithms first devised by Mansinha and Smylie (1971).…”

“…Tsunami generation in the Arabian Sea has been modelled before but not specifically for the purpose of a tsunami hazard risk assessment and particularly for the coasts of Oman (Heidarzadeh et al, 2007;Heidarzadeh and Kijko, 2011;Heidarzadeh and Satake, 2014). Heidarzadeh et al (2007) modelled the effects of a range of tsunami events off the southern coast of Iran using deformation algorithms first devised by Mansinha and Smylie (1971). The results showed the average magnitude earthquake for tsunami generation in this region was between Mw 8 to Mw 8.4 (Heidarzadeh et al, 2014a); such an event could produce a tsunami that would reach the coast of Iran within 15 minutes with wave amplitudes of up to 4 m at locations perpendicular to the fault.…”

“…More recent models have utilised the GEBCO bathymetric dataset to provide probabilistic constraints on the potential amplitude of tsunami in the northwestern Indian Ocean (e.g. Heidarzadeh et al, 2008;Heidarzadeh and Kijko 2011;Heidarzadeh and Satake, 2014).…”