The 1985 earthquake was 30 times more powerful than the one on Tuesday. Advertisement Continue reading the main story“It would appear that the regulator is not performing its duty,” the study concluded. The 1985 quake, at magnitude 8.1, released about 30 times more energy than Tuesday’s magnitude 7.1 quake. There were other differences as well: the 1985 quake was shallower, and even the orientation of the faults — the direction the rocks moved in — was different. High-frequency waves of energy generated by the quake dissipated over the miles to Mexico City, leaving mostly low-frequency waves to reach the capital.

Source: New York Times September 23, 2017 15:28 UTC