Seismic Attenuation Models for Peak Ground Acceleration Along Source-to-Site Trajectories from the Pacific Subduction Zone to the City of Querétaro, México

Abstract

This article presents four seismic attenuation relationships to estimate the Peak Ground Acceleration (PGA) in rock from interplate earthquakes in the city of Querétaro, México, by analyzing specific source-to-site trajectories: Jalisco-Colima, Michoacán, Guerrero, and Oaxaca. The motivation for this study lies in the fact that, to date, the state of Querétaro has a PGA attenuation relationship limited to earthquakes with epicenters in Guerrero. While previous research has analyzed trajectories from Colima, Guerrero, and Oaxaca, it has omitted data from earthquakes with epicenters in Michoacán. This research proposes a functional form that considers the variables of moment magnitude, depth, and hypocentral distance, excluding the site effect variable to focus on the response in rock. The regression analysis was performed using the one-stage maximum likelihood method. The attenuation relationships obtained in this research are compared with previously developed models, and the observed differences are shown through attenuation curves and residual analysis. The attenuation relationships were validated using seismic data from actual data observations records. It is concluded that the proposed models allow for the estimation of PGA with overestimations and underestimations of 1.44, 1.81, 2.01, and 1.91 for seismic events with epicenters in Jalisco-Colima, Michoacán, Guerrero, and Oaxaca, respectively. Trajectory analysis allowed for the estimation of average Peak Ground Acceleration values ​​in the city of Querétaro of 0.09 cm/s², 0.67 cm/s², 0.37 cm/s², and 0.13 cm/s² for earthquakes with epicenters in Jalisco-Colima, Michoacán, Guerrero, and Oaxaca.