The Colima–Jalisco (CJ) region in northwestern Mexico has generated large-magnitude earthquakes at least since 1800. For example, during the last century, three large, destructive, shallow-thrust subduction earthquakes occurred on 3 and 18 June 1932 with MS of 8.2 and 8, respectively, and on 9 October 1995 (Mw 8, MS 7.4). This historical seismicity and the lack of seismic recordings in the CJ region pose important constraints for the computation of reliable seismic-hazard studies for sites in this region of Mexico. Towards this aim, we have used a hybrid method to generate broadband (BB) synthetics for the Mw 8 CJ 1995 earthquake for the recording sites of the near (MZ) intermediate (CG), and far (COL) fields. The low-frequency (LF, ≤0.5 Hz) synthetics were simulated by applying a 3D finite-difference method, and the high frequencies (HF, >0.5 Hz) were generated by the empirical Green’s function technique. Finally, matched filters were applied to the LF and HF synthetics to obtain the BB time series. The LF synthetics were computed from a finite-fault description of the source with four asperities in a 2.5D model constrained by gravity and seismological data. Our preferred model includes an approximation of a thin accretionary prism. For the HF modeling, we also used the four-asperity source model as well as the recordings of the foreshock and aftershock of the Mw 8 1995 mainshock. Based on the comparisons of the BB synthetics with the observed strong ground motions for the 1995 CJ earthquake at the three stations, we believe that our hybrid method is a first step toward the generation of more reliable estimates of the seismic hazards in CJ region. Further improvement in the hazard estimates depends on the urgent deployment of seismological and strong ground motion infrastructure in the CJ region.

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