When last September’s magnitude 8.2 Tehuantepec earthquake rose from the deep, scientists thought it was the expected big one in the subduction zone off Mexico’s southern coast.
After an extensive analysis, however, a 13-member research team led by Diego Melgar of the University of Oregon concluded this one was something else and may represent a potential new hazard along the Pacific Coast of Central America. The findings were published in a paper in Nature Geosciences.
“We don’t yet have an explanation on how this was possible,” said Melgar, an assistant professor in the Department of Earth Sciences. “We can only say that it contradicts the models that we have so far and indicates that we have to do more work to understand it.”
Subduction zone megaquakes generally occur near the top of where plates converge. Initially, the 2017 event was thought to be in such a location, where the Cocos ocean plate is being overridden, or subducted, by a continental plate. The zone had not had a quake of such magnitude since 1787.
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