Northridge Fault Shows Almost No Movement

The Northridge fault, which was expected to keep readjusting for the next 20 years, has slowed to a crawl, according to JPL scientists who have been monitoring the area closely since before the Jan. 17, 1994, magnitude 6.7 quake that killed 60 and injured 7,000. Geophysicist Andrea Donnellan, who has studied the region for 15 years, said the fault has probably stopped moving because it originated in a lower, colder part of the crust.

The part of the Earth’s crust where the Northridge quake originated is 500 degrees to 1000 degrees colder than the region that spawned the magnitude 7.6 Landers quake in the Mojave Desert in 1992. The slowdown of Northridge fault activity does not mean the area will never shake again. More aftershocks are still possible, Donnellan said, and other nearby faults could rupture as well.