California quake occurred in very seismically active region
By JOHN ANTCZAK
Associated Press
LOS ANGELES (AP) — The big earthquake that rocked the far north coast of California this week originated in an area under the Pacific Ocean where multiple tectonic plates collide, creating the state’s most seismically active region. The Mendocino Triple Junction is the meeting place of the Gorda, Pacific and North American plates, which are massive moving slabs of Earth’s crust. The Gorda Plate is diving under the North American plate in a process called subduction. Tuesday’s magnitude 6.4 earthquake occurred southwest of the Humboldt County community of Ferndale. The U.S. Geological Survey says analysis indicates it likely occurred within the Gorda Plate.
