Earthquakes Can Lead to Large Aftershocks on Other Fault Lines: Study

A major earthquake on one fault line can trigger large aftershocks on separate faults, according to a new study by the Scripps Institution of Oceanography at UC San Diego.

The study found that ruptures on fault lines can cascade and lead to aftershocks that feel as strong as large earthquakes. The Sept. 9 study looked at 48 major aftershocks to earthquakes around the world between 2004 and 2015.

In one instance, scientists discovered that a 7.0-magnitude off the coast of Indonesia in 2004 triggered two large aftershocks 124 miles away.

“These aftershocks miles away reveal that stress can be transferred almost instantaneously by the passing seismic waves from one fault to another within the earthquake fault system,” a news release from the Scripps Institution said.

Scientists said the findings had implications for California in that they could help seismologists predict what fault lines could be impacted after large earthquakes.

The study found that the locations of a main quake and an aftershock may not be directly connected.

“Multiple fault system interactions are not fully considered in seismic hazard analyses, and this study might motivate future modeling efforts to account for these effects,” Peter Shearer, the senior author of the study, said in the news release.

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