Resumen de Estimation of local magnitude in northeastern Sonora, Mexico, using empirical relations based on recorded duration

Gina P. Villalobos Escobar, Raúl R. Castro

• Most of northern Mexico is tectonically and morphologically situated in the southern Basin and Range Province (Suter and Contreras, 2002). The region of Sonora is particularly interesting, because the largest historical earthquake (3 May 1887, Mw 7.5) occurred in this province. The town of Bavispe was destroyed during this earthquake (Aguilera, 1888), and the seismic source generated the longest recorded normal-fault surface rupture (101.8 km) in historic time (Suter, 2006). The major fault zone of this earthquake includes (from south to north) three neighboring segments: Otates (length l=18.9??km), Teras (l=20.7??km), and Pitáycachi (l=43.8??km) (Fig. 1). These segments are separated by ~30??km in between, and the basins are about 10 km wide (Suter and Contreras, 2002).

  A seismic network, Red Sísmica del Noreste de Sonora (RESNES), was installed in this region to study the seismicity related to the Basin and Range faults of northeastern Sonora (Castro et al., 2002; Romero et al., 2004) and to monitor the major normal faults that generated the 3 May 1887 event (Castro et al., 2009). The stations of this seismic network consist of Kinemetrics digital recorders (model K2) with internal Episensors that record three components of ground acceleration with a sample rate of 200 samples per second...