Controversial results from a new study by the United States Geological Survey have provided a shocker to scientists by indicating seismic waves from the 8.6 East Indian Ocean earthquake on April 11 circled the earth multiple times, triggering more than a dozen major earthquakes around the globe within a week. The evidence could change the definition of “aftershocks” as scientists have known them for generations. According to the USGS report, there was a “100-fold increase in seismicity” on the other side of the earth in Baja, Calif., which experienced “13 events in the following two days,” including 6.0 and 7.0 shakers. Japan was another location thousands of miles away from the original temblor where large quakes were triggered.
And what is so shocking to the scientific community?
“While aftershocks have traditionally been defined as those smaller earthquakes that happen after and nearby the main fault rupture, scientists now recognize that this definition is wrong,” a statement by the USGS reads. “Instead, aftershocks are simply earthquakes of any size and location that would not have taken place had the main shock not struck.” The 8.6 quake, which took place on a strike-slip fault similar to the San Andreas Fault running through California, was called “unprecedented” by the USGS. “No other recorded earthquake triggered as many large earthquakes elsewhere around the world as this one,” said USGS seismologist Fred Pollitz, who led the team of geologists conducting the study. “The research has helped change the very definition of ‘aftershock.’” Within six days after the 8.6 quake, 16 earthquakes registering 5.5 or higher on the Richter scale were triggered around the earth. Coincidence? Only one similarly sized shaker occurred during the six days before the major East Indian Ocean quake.