California earthquake: How a crumbling tectonic plate in the Pacific hits the West Coast
The so-called Juan de Fuca plate runs just north of California and is being subducted or driven under North America.
According to researchers at the University of California, Berkley, the oceanic plate has split wide open, triggering activity on the land.
The theory was presented on July 3 in the journal Geophysical Research Letters by UC Berkeley geologists William Hawley and Richard Allen.
The researchers wrote in their study: “A hole in a subducted plate, in the mantle beneath North America, may cause volcanism and earthquakes on the surface of the Earth.
READ MORE: Will the Big One erupt along the San Andreas fault line?