HR: 08:20h
AN: S21B-02    [PDF]
TI: The Mexican Sistema de Alerta Sismica (SAS) Experience
AU: Espinosa-Aranda, J
EM: maranda@servidor.unam.mx
AF: Centro de Instrumentacion y Registro Sismico, A. C., Anaxagoras 814 Col, Narvarte, Mexico, DF 03020 Mexico
AU: * RodrĄguez, F
EM: humberto.rodriguez@roconsultores.com
AF: Ro Consultores Especializados, S.C., Providencia 1206-2 Col, del Valle, Mexico, DF 03100 Mexico
AB: The Mexico City's SAS is an Early Warning System developed in accordance with recommendations of foreign and national seismology experts, after the disaster generated in 1985 by the M8.1 Michoacan earthquake. The SAS aim is to help mitigate future seismic disasters in Mexico City (MC), mainly if the big forecast "Guerrero Earthquake" hits. In 1991 the SAS started its service in an experimental basis for evaluating its performance both with a group of basic education students in public schools, and with the emergency stop function for the Mexico City Metropolitan Subway System (METRO of MC); after this The Federal District Government (FDG) opened the SAS as a public service in August, 1993, shortly after the SAS warned, with more than 60 seconds of anticipation, the incoming effect of May 13, 1993, M5.8, and M6 double earthquake originated more than 300 Km from MC between Guerrero and Oaxaca, on the coast. That year, an initial technical flaw generated one false alert signal; the cause was readily corrected. The SAS has 12 seismic sensor stations covering a stripe close to 400 X 100 Km on the Guerrero's coast, between Papanoa and Punta Maldonado, that send information through a dedicated radio relay system to the SAS Central Control in MC., using the valuable support of some TELMEX field installations. Until August, 2003, the SAS sensor system has detected more than 1550 earthquakes in the 2.5$<$M$<$7.3 range, being capable to discriminate M$>$5 magnitude events, which are the ones felt in MC. The SAS has generated 57 warning signals with an average of 60 sec in advance to earthquake effects: 46 of restricted use for M$<$6, and 11 of public use for M$>$6 events. Public warnings have the automatic broadcast support of many commercial radio AM/FM and TV stations in Mexico City and Toluca valleys. The FDG controls the SAS signal service that includes the more frequent events (from M$>$5 up), asking the user to develop procedures and practice useful actions to mitigate seismic disasters. Each validated SAS seismic warning automatically generates and sends the event information by fax and e-mail to the DFG and Civil Protection Authorities, users and news media; it also sends information about the SAS operating conditions to service technicians, via radio, and phone.
DE: 7212 Earthquake ground motions and engineering
DE: 7223 Seismic hazard assessment and prediction
DE: 7294 Instruments and techniques
SC: Seismology [S]
MN: 2003 Fall Meeting