SASMEX

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Sistema de Alerta Sísmica Mexicano , SASMEX for short , is the Mexican earthquake warning system . Its aim is to use advance warning to minimize the number of victims and damage to sensitive infrastructure from earthquakes.

development

Earthquake alarm receiver on the premises of the University of Mexico City

Mexico is located in one of the most seismically active regions in the world. The devastating earthquake in Mexico City in 1985 triggered the establishment of the world's first earthquake warning system. Since 1989, the non-profit organization Centro de Instrumentación y Registro Sísmico (CIRES) in Mexico City has been working on the development of the Sistema de Alerta Sísmica (SAS), which has been in operation since August 1991. SAS distributed earthquake warnings on the metro , schools, broadcasters and other facilities in the Valley of Mexico and the Valley of Toluca .

After the earthquake of June 15, 1999, the city of Oaxaca de Juárez also decided to set up an earthquake warning system. This system called Sistema de Alerta Sísmica de Oaxaca (SASO) was also developed by CIRES and has been in operation since 2003.

The city councils of Oaxaca and Mexico City decided in 2005, together with the Mexican Ministry of the Interior, to integrate the two warning systems SAS and SASO into a common system. It got the name Sistema de Alerta Sísmica Mexicano (SASMEX). By installing additional sensors along the Mexican Pacific coast , other regions and all major cities in the country can now be served by the warning system.

functionality

Most earthquakes in Mexico occur near the Central America Trench , where the Cocos Plate and Rivera Plate submerge ( subduction ) under the North American Plate . SAS originally only relied on the measurement of the fast primary waves (P waves) , which arrive on average around 60 seconds before the slower but destructive secondary waves (S waves) in Mexico City. This time difference could be used for the earthquake warning.

Thanks to the sensors on the coast, SASMEX can quickly calculate the epicenter and magnitude and transmit this data via radio. Depending on the expected intensity , a preventive alarm or a public alarm is triggered automatically .

  • Preventive alarm: In the event of moderate earthquakes, local authorities, ambulance, fire brigade, sensitive infrastructure facilities (transport companies, electricity companies, hospitals, etc.) and private companies or people who have installed appropriate receivers are alerted.
  • Public alarm: In the event of strong earthquakes, in addition to the measures described, the alarm is remotely fed into radio broadcasts. And when the alarm message is received, a special radio receiver triggers a warning signal via sirens ; in some cities, pre-recorded warnings are issued over loudspeakers in public places.

literature

  • JM Espinosa-Aranda, A. Cuéllar, G. Ibarrola, R. Islas, A. García, FHRodríguez, B. Frontana: The Seismic Alert System of Mexico (SASMEX) and their Alert Signals broadcast results . In: Proceedings of the 15th World Conference on Earthquake Engineering . Lisbon 2012 (English, online on the website of the Indian Institute of Technology Kanpur (PDF; 611 kB)).

Web links