Numerical study of the impact of nonlinear parameters on tsunami wave modeling - A case study: Chabahar Bay

For the earthquakes and resulting tsunamis assessment in the Makran subduction zone, various earthquake scenarios defined, and the tsunamis waves associated with them modeled numerically. Based on the latest research results using thermal modeling, the maximum earthquake magnitudes considered in scenarios are 8.7 and 9.1. In contrast to previous studies that simulated Makran tsunamis using only a large-scale model containing topographic and hydrographic data with low resolution, the current research introduced a local model with finer spatial networks alongside the global model to calculate run-up accurately. Tsunami modeling was carried out considering different scenarios, using Boussinesq and non-linear shallow water models. The results indicate a significant importance difference in using Boussinesq and non-linear shallow water models. For smaller earthquakes like 8.3, the difference is much greater than for larger earthquakes like 9.1. This difference in the 8.3 earthquake may be due to the penetration of tsunami waves into the Chabahar bay and wave breaking inside the bay, where the Boussinesq model is more capable of accurately simulating wave breaking compared to the non-linear shallow water model. Meanwhile, for the 9.1 earthquake, due to the very high waves, most waves break before entering the bay and we observe less wave breaking inside the bay compared to the 8.3 earthquake scenario.