Deprem Kaynak Mekanizması Parametreleriyle Sayısal Tsunami Simülasyonları: 08 Eylül 2017 Chiapas-Meksika Depremi (M_w 8.2) ve Tsunamisi

Modeling of seismological data by inversion processes provides earthquake source mechanism solutions (e.g, strike, dip and rake angles of the fault plane, earthquake focal depth and seismic moment etc.) and kinematic and dynamic source parameters (e.g, fault length, fault width, maximum and average displacement amount, stress drop, rupture duration etc.). These parameters are used as input constraints for further analysis, particularly for tsunami modeling. In this study, we provide an example of teleseismic waveform inversion and numerical tsunami simulation studies in order to demonstrate the importance and necessity of seismological data in tsunami studies. We obtained source mechanism solution and finite-fault slip distribution model of the destructive 08 September 2017 (M_w 8.2) earthquake occurred in Chiapas (Mexico) region by inverting long period P-and SH-and broad-band P-waveforms recorded at telesismic stations. Overall results show that this earthquake occurred with a normal faulting mechanism and a very small strike-slip component at a focal depth of 54 km, and a very simple rupture. In addition, slip distribution model of this event showed that the rupture occurred on the NW-SE trending fault plane has an area with a fault length of about 125 km and fault width of 55 km with a maximum displacement amount of 22.10 m. Then, numerical tsunami simulations were performed based on a uniform slip model and GEBCO-BODC bathymetry data with 30 arc-sec resolution, and propagation of tsunami waves trigerred by this earthquake in the Pacific Ocean have been modeled. Synthetic tsunami waves were calculated for various coasts and they were further compared with the real-time tsunami data recorded by Deep Ocean Assesment and Reporting of Tsunami (DART) and tide gauges. As a result, it is observed that synthetic tsunami waves are relatively compatible with real-time recordings. However, this consistency is particularly high for DART buoy records in open ocean and relatively less for tide gauge records on shorelines. Hence, we suggest that better modeling of tsunami waves recorded at tide gauges on the coasts might be achieved by using a high-resolution bathymetry data and a detailed finite-fault slip distribution model of earthquakes in numerical simulations.