Ground motion prediction model for southeastern México removing site effects using the Earthquake horizontal-to-vertical ratio (EHVSR)

Abstract

A ground motion attenuation model (ground motion prediction equation, GMPE) for southeastern Mexico is proposed. The attenuation model was built as a function of magnitude, and distance. A number of 86 earthquakes were used with 5.0 ≤ Mw ≤ 8.2 (including the recordings of the 9/7/2017, Mw8.2 Tehuantepec earthquake), and distances between 52 ≤ R ≤ 618 km. They were recorded in nine stations of the Engineering Institute of the National Autonomous University of Mexico (II-UNAM) accelerometric network installed in the states of Chiapas, Oaxaca, Tabasco and Veracruz. From all recordings of each of these stations, we removed site effects, which were estimated using the average Earthquake Horizontal to Vertical Spectral Ratio (EHVSR). This work points out the need to remove site effect in the current GMPEs, which tends to overestimate this effect.