Intraslab versus Interplate Earthquakes as Recorded in Mexico City: Implications for Seismic Hazard Available to Purchase

We study the relative importance of interplate and intraslab earthquakes in the seismic hazard of Mexico City by analyzing accelerograms recorded at the hill-zone site of CU (1964–2012) and the lake-bed site of SCT (1985–2012). A_max exceeded 6 gal during 20 earthquakes at CU during this period. Of these, eight were intraslab events so that the exceedance rate of A_max ≥ 6 gal from both types of earthquakes is roughly about the same. The estimated return period of A_max of 30 gal from the two types of earthquakes is ∼100 yrs. If we consider high-frequency (2.5–8.5 Hz) acceleration (A_max^HF) at CU, then the top 7 out of the 20 events are all intraslab earthquakes. Even at the lake-bed site of SCT, the A_max^HF values are, generally, associated with intraslab earthquakes. It follows that the risk from both types of earthquakes to low-rise construction in the city needs careful assessment.