Seismologists Dispute Magnitude of Quake

Harvard University seismologists, using recordings of this week’s earthquake off the Mexican coast from seismographic stations worldwide, have calculated the strength of the temblor as magnitude 7.4, not 7.8.

This would mean it was only about half as big as stated by the U.S. Geological Survey.

Harvard geophysicist Goran Ekstrom said the smaller size helps explain the comparatively low death toll of 29.

Varying calculations of a quake’s strength are common, and some disputes last for many years. Disagreement remains over the great San Francisco quake of 1906.