Mexico primed for more quakes

This September, two earthquakes devastated Mexico in rapid succession. The first, a Sept. 7 magnitude 8.2 temblor near the southern state of Chiapas, killed nearly 100 people. Just 12 days later and a few hundred miles away, a magnitude 7.1 quake shook central Mexico; hundreds more died, including 19 children when their elementary school collapsed.

The chance of the two tragedies occurring in such a short span of time by sheer coincidence was just one in 200, said seismologist Ross Stein. But there is no evidence to suggest that the quakes were connected.

However, Stein’s research suggests that the combination of temblors added to the stress along faults in the earthquake-prone country, possibly doubling the likelihood that another earthquake of magnitude 7 or greater will strike next year.

“Another shoe could drop,” said Stein, a longtime U.S. Geological Survey scientist who is now chief executive of the earthquake-awareness company Temblor. He presented his findings last week at the annual meeting of the American Geophysical Union.

Xyoli Perez-Campos, a seismologist at the National Autonomous University of Mexico, said that as of last week, the Sept. 7 quake had triggered nearly 13,000 aftershocks, including a magnitude 6.1 quake near Oaxaca.

“Earthquakes tend to beget earthquakes,” Stein said.

Mexico sits beside a spot where two tectonic plates meet. In 2018, the country had a 25 percent chance of experiencing a quake nearly as bad or worse than magnitude 7. But considering the stresses from this year’s quakes, that chance is now as high as 55 percent, Stein said.

He hopes it will spur people to prepare. Most quake fatalities are typically tied not to the magnitude of the quake, but the quality of the infrastructure.