The 1985 Mexico City earthquake was an earthquake that shook Mexico City on 19 September 1985. The country severed devastating casualties, as well as serious damage to the capital city. The earthquake struck at 7:19 local time. It measured 8.1 on the Richter Scale, and surrounding Mexican States such as Jalisco, Guerrero, and Michoacán were also affected, but the damage was only mild to moderate. Most of the damage was concentrated in a 25 km2 area of Mexico City, 350 km from the epicentre. The damage cost three to four billion USD.
The earthquakes epicentre is located in the Pacific Ocean, off the coast of Michoacán, some 350km away from Mexico City. It lies in the Cocos Plate subduction zone, in the Michoacán Seismic Gap, a section of the fault line. The Cocos Plate pushes against and slides under the North American Plate, creating a convergent plate boundary (see diagram below). This caused many natural disasters, including 42 magnitude 7.0 earthquakes or the 1,985 Mexico City earthquake. The earthquake was felt as far as Los Angeles and Houston, over 825 000 square kilometres during the main event (its energy equivalent to approximately 1 114 20-kiloton atomic bombs).
Mexico suffered bad consequences after the earthquake: 10,000 dead (some sources state that the death toll may reach up to around 30,000), 30,000 injured, 250,000 homeless and 200,000 jobless. Around 5,000 bodies were recovered from the debris. Of the remaining survivors, about 40% of the people were left without electricity and around 70% were left without telephone service. Cuauhtémoc, which includes a historic downtown, suffered the most damage of the entire city. Water drainage and pipes broke in 163 places, which resulted in having water supply either cut off or contaminated. 137 schools collapsed and 1,687 of them were damaged. In addition, over 800 buildings were damaged, including offices, schools and hospitals and a communications tower. Mexico City had no communications with the outside world for many days. When the damage was finally assessed, 3,000 buildings in Mexico City were demolished and another 100,000 suffered serious damage. The property damage mounted up to 5 million USD.
One preparation that was been made for future disasters was an alarm system, Sistema de Alerta Sísmica (SAS), which sends early-warning messages electronically from sensors along the coastal subduction zone in Guerrero. An alarm is supposed to go off if an earthquake of over magnitude 6.0 Is detected.
One preparation that was been made for future disasters was an alarm system, Sistema de Alerta Sísmica (SAS), which sends early-warning messages electronically from sensors along the coastal subduction zone in Guerrero. An alarm is supposed to go off if an earthquake of over magnitude 6.0 Is detected.
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