A critical review of the seismic hazard in the State of Colima, México.

Abstract

This study presents a comprehensive review of the seismic hazard in the state of Colima, Mexico, using a Probabilistic Seismic Hazard Analysis (PSHA) approach. We propose a new seismogenic regionalisation based on an updated and declustered earthquake catalogue spanning the period from 1787 to 2019. The parameters for both the Truncated Gutenberg-Richter and the Characteristic Earthquake recurrence models are determined. The variation of seismic intensity across the study area was determined through the implementation of Next Generation Attenuation (NGA) models, which can account for geological, stratigraphic, and site-effect conditions. The analysis results are presented as uniform hazard spectra for rock site conditions in the cities of Manzanillo and Guadalajara and are compared directly with the spectra from the Manual de Diseño de Obras Civiles of the Comisión Federal de Electricidad (CFE, 2015), which is applicable as national guidelines for Seismic Design. Additionally, seismic hazard maps are generated, showing the spatial distribution of peak ground acceleration (PGA) and spectral accelerations for key structural periods, corresponding to return periods of 150 and 475 years. The results indicate that while the estimated seismic hazard for low return periods is consistent with that proposed by the CFE (2015), for the higher return period of 475 years, the obtained accelerations exceed the values recommended by these design’s guidelines by up to 20%. This discrepancy suggests that an update of the seismic hazard for the western region of Mexico is pertinent, with potential implications for the seismic safety of critical infrastructure.