Numerical simulation and observation analysis of Mexico M W 8.2 earthquake tsunami on 8 September, 2017

Abstract

On September 8, 2017, at 4:49 (UTC) a magnitude Mw8.2 earthquake took place off the coast of Oaxaca State, Mexico, focal depth of 30 km. Meanwhile, the earthquake triggered moderate intensity tsunami. The tsunami impacted hundreds of kilometers of the coast of Mexico. Tsunami waves were subsequently recorded by Deep-ocean Assessment and Reporting of Tsunami (DART) buoys in the Pacific Ocean and tide gauges off the coast. In this paper, we apply observational data of 2 DART buoys and 6 tide gauges, and isolate the tsunami waves from boservational data by de-tiding and filtering method, and futher analyze the frequency characteristics of the tsunami waves by wavelet analysis. To compute the co-seismic deformation, we employ the half space elastic theory, and then we analyze the near-field characteristics of this tsunami by numerical simulation with MOST (Method Of Splitting Tsunamis) model. The results based on the observational and simulation data show that, apart from the magnitude and geometric distribution of the earthquake, near-field tsunami waves are mainly controlled by topographic distribution off the coast. Especially, the amplitude of tsunami waves may have amplification effect when interacting with specific topography, which will cause much more damage of the tsunami.