April 18, 2014 Earthquake: Guerrero, Mexico City

Felt (VI) at Acapulco, Atzacan, Buenavista, La Loma and Mexico; (V) at Atoyatempan, Coatepec, Los Reyes, Morelia, Patzcuaro, Tlalnepantla and Zacamulpa; (IV) at Cuernavaca, Ixtapa, Jiutepec, Naucalpan, Nezahualcoyotl, Puebla, Tecpan, Totoltepec, Veracruz and Vista Hermosa. Felt in much of central and southern Mexico. Petatlan, Guerrero, Mexico - CDI: 8; Acapulco, Guerrero, Mexico - CDI: 7; Coacoyul, Guerrero, Mexico - CDI: 7; Zapotiltic, Jalisco, Mexico - CDI: 7; La Union, Guerrero, Mexico - CDI: 7

Tectonic Summary

The April 18, 2014 M 7.2 earthquake near the western coast of Mexico occurred in the state of Guerrero, 265 km southwest of Mexico City. The earthquake occurred as the result of thrust motion at shallow depths. The initial location, depth, and mechanism of the April 18 earthquake are broadly consistent with slip on or near the plate boundary interface between the subducting Cocos oceanic sea plate and the North America plate.

The broad scale tectonics of the west coast of Mexico are controlled by the northeastward subduction of the Cocos plate beneath the North America plate at a rate of approximately 65 mm/yr. Earthquakes are a common occurrence along the Middle American subduction zone; the April 2014 earthquake occurred just northwest of the rupture area of the 1957 M 7.8 Guerrero Earthquake. Since 1975, 23 events of M > 6.0 have occurred within 200 km of the April 2014 earthquake, including events of M 8.0 and M 7.6 (September 1985), M 7.2 (October 1981), and M 7.5 (March 1979), all to the northwest. The 1981 and 1979 events caused 9 and 5 shaking-related fatalities, respectively. The 1985 M 8.0 earthquake, 195 km to the northwest of the April 2014 event, led to more than 9,500 fatalities, mostly in Mexico City, and generated small, local tsunamis. That event was influential in initiating efforts to establish earthquake early warning systems in Mexico City.

The April 2014 earthquake occurred within the “Guerrero "Seismic Gap" - an approximately 200 km long segment of the Cocos-North America plate boundary identified to have experienced no significant earthquakes since 1911 (M 7.6). The plate interface in this region is known to be locked, with an earthquake of M 8.1-8.4 thought possible should the entire gap rupture in a single event.

(above from reference #13456)

A 7.5-magnitude earthquake struck southern Mexico's Guerrero state Friday morning, the U.S. Geological Survey said... At least one building was damaged in Mexico City, nearly seven hours away. (reference #10906)

It was felt across at least a half-dozen states and Mexico's capital, where it shook for at least 30 seconds. Around the region, there were reports of isolated and minor damage, such as fallen fences, trees and broken windows. Chilpancingo, capital of the southern state of Guerrero, where the quake was centered, reported a power outage, but service was restored after 15 minutes. (reference #10907)

At least 127, mostly adobe homes were damaged in Guerrero. In the state capital Chilpancingo, a tower of the cathedral suffered cracks along with a few other public buildings, a spokesman for local emergency services said. But there were no reports of deaths or major damage. Some people in Mexico City fled homes in panic when the quake hit. Electricity was cut off in parts of the city and some residents said paintings fell off the walls, while small parts of masonry crumbled inside apartment buildings... Lasting more than a minute, the quake was felt as far away as the states Puebla and Tlaxcala in central eastern Mexico. It also caused some minor landslides and damaged a bridge on the road between Acapulco and the resort of Zihuatanejo to the northwest, emergency services in Guerrero said. (reference #10910)

USD 49.5 million in economic loss (reference #13727)