Tsunami modeling for Shabla area using HySEA software

There are several areas of interest in the Black Sea with evidence of past tsunami generation (Papadopoulos G.A. et al, 2011, Yalciner A. et al, 2004, Altinok Y., 1999), such as Shabla (Bulgaria) located near the Romanian coast, where a total of 22 events have been identified, including four in the Shabla area.

We have conducted multiple tsunami-modeling scenarios for the Shabla area using HySEA (Hyperbolic Systems and Efficient Algorithms) software, employing two different resolutions (30 and 15 meters) to estimate maximum possible wave heights for various earthquake input parameters (e.g., different depth values and fault plane solutions). The bathymetry used for the simulations is based on the GEBCO 2020 Grid.

A comparison between simulations with resolutions 30 and 15 meters, using the following earthquake parameters—latitude 44.02, longitude 34.5, depth 5 km, fault length 66 km, fault width 18 km, displacement 2.61, strike 211, dip 65, and rake 171—shows maximum wave heights of 1.32 m for a resolution of 30 m, and 2.29 m for a resolution of 15 m. Other simulations with different earthquake parameters indicate a worst-case scenario of 3.03 m wave heights for resolution 15 and 1.14 m for resolution 30. Additional cases show wave heights of 1.21 m for resolution 15 and 0.61 m wave heights for resolution 30. The general trend indicates higher wave heights for resolution 15, in some cases up to double those obtained with resolution 30. This highlights the importance of using high-resolution simulations, especially near the coast, to reduce numerical dissipation effects.

Although only few examples are presented here, numerous simulations were performed using historical earthquake parameters. Together with other tsunami-related research, these results are intended to be disseminated along the Romanian touristic coastal area to raise public awareness of the tsunami hazards along the Black Sea coast.