Tsunami hazard in the Caribbean coast of Honduras due to large earthquakes occurred along the Cayman Trough at the northwest boundary of Caribbean plate

摘要

In 2018, a large earthquake (Mw7.6) occurred in the Swan Island Fault zone at the northwest boundary of the Caribbean plate. This earthquake generated a small tsunami of 20 cm. However, Puerto Cortes in Honduras is located close to the Swan Island Fault zone. Evaluation of tsunami hazard at Puerto Cortes due to large earthquakes along the fault zone is important. We first estimated the fault parameters of the 2018 Swan Island earthquake using W-phase inversion technique. Then, the moment magnitude of 7.6, the fault length of 134 km, the fault width of 24 km, and the slip amount of 5.1 m were estimated. In addition to those estimates, a small fault dimension of the earthquake, 40 km × 20 km, with a slip amount of 20.8 m was considered. Those two fault models were used to compute tsunami inundation at Puerto Cortes. The tsunami computed from the small fault inundated a large area in Puerto Cortes including the port area. The effect of co-seismic horizontal displacement of ocean floor also enhanced the tsunami inundation at Puerto Cortes. Those results indicate that preparation for future tsunami hazard in Puerto Cortes is important although no significant tsunami was generated historically.