Deterministic Tsunami Hazard Assessment for a Nearshore–Onshore Domain close to the Strait of Hormuz: The Overlooked Threat of the Western Makran Segment and Tidal Sensitivity

The Makran Subduction Zone (MSZ) represents a critical tsunamigenic structure in the northwestern Indian Ocean. While the historical seismicity of the eastern segment has been extensively studied following the ۱۹۴۵ earthquake, the hazard potential of the western segment, specifically its threat to strategic energy infrastructure near the Strait of Hormuz, remains poorly constrained. This study presents a high-resolution deterministic tsunami hazard assessment for the Kooh Mobarak coastal onshore developments and its associated marine facilities. Utilizing the ComMIT/MOST numerical model within a nested grid framework, twelve fault rupture scenarios ranging from Mw ۸.۰ to ۹.۰ were simulated across the western, central, and eastern Makran segments. The results challenge conventional hazard zonations, demonstrating that a rupture in the Western segment (Mw ۸.۹) generates wave heights (~۲.۸ m) and current velocities (>۲.۰ m/s) at the Kooh Mobarak area that are comparable to those of a worst-case Central Makran scenario (Mw ۹.۰). Furthermore, a sensitivity analysis regarding the initial tidal level reveals a critical hydrodynamic dichotomy: while increasing the water level to Mean High Water Springs (MHWS) slightly attenuates the pure tsunami amplitude due to reduced non-linear shoaling, it significantly elevates the Total Water Level, thereby expanding the inundation extent into backshore tidal creeks. These findings underscore the imperative of adopting a dual-criterion design approach that incorporates near-field western ruptures and compound tidal interactions to ensure the resilience of critical coastal structures.

کلیدواژه ها:

Makran Subduction Zone ، Tsunami Modeling ، Strait of Hormuz ، Tidal Sensitivity ، Hydrodynamic Loads