Three Aftershocks of Jan. 17 Quake Rattle Southland

Three aftershocks of the Jan. 17 Northridge earthquake bumped and rolled through the San Fernando Valley within minutes of each other Monday night, sending out shock waves felt throughout the Los Angeles area.

No serious damage or injuries were reported.

The first quake, a magnitude 3.5, was centered three miles east northeast of San Fernando at 7:36 p.m., said Caltech seismologist Kate Hutton.

The second, magnitude 3, struck the same area at 7:48 p.m., followed by a magnitude 4.5 seconds later, centered three miles east of San Fernando, Hutton said.

The temblors occurred “in a very active part of the Northridge aftershock zone,” she said.

Hutton characterized the temblors as a “sequence within a sequence,” meaning that while all of them were aftershocks of the Northridge quake, the smaller quakes Monday night were “foreshocks,” a prelude to the third and biggest one.

“Any time we have a quake in Southern California, there is a 5% chance that it will be followed by a bigger quake,” Hutton said.

Although there has been a “fairly steady decline” in frequency of aftershocks since the initial series ended in January, such aftershocks could continue for at least two years, she said. Monday’s was the 57th aftershock of magnitude 4 or greater.

The quakes were felt from the Santa Clarita Valley to Venice and into southeastern Los Angeles County. They also were felt as far west as Oxnard.

The strongest quake emptied the 600-seat theater of the Television Academy of Arts and Sciences in North Hollywood, where several hundred people rushed out of a special Disney anniversary screening, said Jerry Ough, who was in attendance.