Powerful 8.1 magnitude earthquake hits off Mexico

The magnitude 8.1 quake struck offshore Chiapas, Mexico on September 7, 2017 at 11:49 local time (September 8 at 04:49 UTC), leaving more than 90 people dead and another 200 injured.

The earthquake was the strongest to hit Mexico within the past century. The epicenter was in the Pacific Ocean, about 1000 km southeast of the capital and 120 km off the coast, at a depth of 69.7 kilometers, according to the US Geological Survey.

The quake was felt as far as Mexico City and Guatemala City, but mainly affected the states of Tabasco, Oaxaca and Chiapas that are located closest to the earthquake's epicenter. Juchitán, Oaxaca, was the most affected town. According to a government spokesman, 71 people have been killed in the south-west state of Oaxaca alone. Rescue efforts continue at these states and the death toll is likely to rise.

Several buildings collapsed - mainly in Oaxaca State - and about 1.85 million homes lost electricity. Hundreds of families are currently camping in the streets, being afraid of aftershocks. The Mexican Seismological Service reports 721 recorded aftershocks since the initial tremor. The USGS also reported multiple aftershocks, including at least six above 5.0 in magnitude.

A tsunami was confirmed in Mexico by the National Weather Service's Pacific Tsunami Warning Center, with one wave coming in at 1m height. Tsunami waves taller than 3m could hit the coast of Mexico, while 1m waves could reach as far as Ecuador, New Zealand and Vanuatu, the Center reported.

According to USGS, the earthquake occurred as the result of normal faulting at an intermediate depth. At the event location, the Cocos plate converges with North America at a rate of approximately 76 mm/yr, in a northeast direction. The Cocos plate begins its subduction beneath Central America at the Middle America Trench, just over 100 km to the southwest of this earthquake. The location, depth, and normal-faulting mechanism of the September 8th, 2017 earthquake indicate that it is likely an intraplate event, within the subducting Cocos slab, rather than on the shallower megathrust plate boundary interface. Normal-faulting events of the size of this earthquake are typically about 200x50 km (length x width), the US Geological Survey reports.