The Mexican Seismic Alert System (SASMEX): Its Alert Signals, Broadcast Results and Performance During the M 7.4 Punta Maldonado Earthquake of March 20th, 2012

The Mexican Seismic Alert System (SASMEX) comprises the Seismic Alert System of Mexico City (SAS), in continuous operation since 1991, and the Seismic Alert System of Oaxaca City (SASO) that started its services in 2003. The SAS generates automatic broadcasts of Public and Preventive Alert Signals to the cities of Mexico, Toluca, Acapulco and Chilpancingo, and SASO by now only to Oaxaca City. Historically in Mexico City, due to their great distance to the coast of Guerrero, the SAS has issued its Alert Signals with an opportunity average of 60 s. In Oaxaca City the SASO gives 30 s time opportunity, if the earthquake detected is occurring in the Oaxaca coast region, or less time, if the seismic event hits near this town. The paper reviews both systems, its performance characteristics and its recent test by the Ometepec M 7.4 earthquake of March 20, 2012.