A 5.6-magnitude earthquake shook rural northern California on Wednesday, followed hours later by a 7.2-magnitude quake off the coast of northern Japan and two devastating tremors in Venezuela that caused casualties. These events happened within eight hours, sparking online speculation about a possible connection.
But experts say there is no link. According to William Barnhart, assistant coordinator of the earthquake hazards program at the U.S. Geological Survey (USGS), the events share only the fact that they occurred along known plate boundaries with high seismic risk. Their timing on Wednesday was coincidental.
“Earthquakes happen every day across the globe. Most occur far from populated areas. Yesterday was just a very special day when you had a few fairly large earthquakes in places where people felt them,” Barnhart said.
He also explained that a large earthquake can trigger aftershocks in other parts of the world. But Martin Hudson, professor emeritus of civil and environmental engineering at UCLA, said such a chain reaction over thousands of kilometers is unusual: “Looking at the last 100 years, we have never seen earthquakes this far apart being related.”
Compared with the above events, the initial 7.1-magnitude quake in Venezuela may have triggered the subsequent 7.5-magnitude tremor because of their proximity. “A fault zone can be ready to go, and then if you have an earthquake nearby, it pushes the fault over the threshold,” Hudson said. He noted that any given year sees dozens of quakes greater than magnitude 7 globally. He emphasized the tragedy unfolding in Venezuela: “It's a scary coincidence that it hit a populated area.” At least 188 people have been confirmed dead so far.
