No Injuries as 3 Quakes Hit Valley : Aftershocks: Seismologists record the temblors’ magnitudes at 3.5, 3.0 and 4.5 and place the epicenters east of the city of San Fernando.

Three aftershocks of the Jan. 17 Northridge quake 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, a magnitude 3.0, struck the same area at 7:48 p.m., followed seconds later by a magnitude 4.5, centered three miles east of San Fernando, Hutton said.

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

She 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.

“Anytime 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, “so it’s not surprising to us at all to find this kind of activity going on right now.”

Monday’s was the 57th aftershock of 4.0 or greater since January, she said.

The quakes were felt from the Santa Clarita Valley on the north to Venice and into southeastern Los Angeles County and westward through Ventura County to Oxnard, authorities said.

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 there.

Some theater patrons returned a few minutes later, he said.

The temblor also shook up Christmas shopping crowds at Northridge Fashion Center, where repair work on heavy damage by the January quake is still under way. “The place was packed,” one woman told television station KCAL. “When the earthquake hit, I just started shaking and everyone just headed for the doors.”

Some reported the strongest quake as sharp. Others said it had a rolling, wavy effect.

Emma-Ruth Nehus of Granada Hills, a few miles from the epicenter, said the second aftershock felt much larger than the scientists said.

“It felt like at least a 5.0 here. My chandelier was swinging at least eight inches,” Nehus said. “We had $100,000 worth of damage from the last earthquake. I’m 70 years old I don’t want to spend the rest of my life rebuilding the house from the earthquakes.”

However, she said her house was not damaged Monday.

In Winnetka, Pamela Castruita filled her flashlight with batteries and checked on her family’s water supply as soon as the first shaker hit.

“My husband thought I was nuts, but I was scared,” said Castruita. “Then the next one hit and we all ran outside and checked with the neighbors.”

Telephone service in the San Fernando Valley was briefly interrupted after the temblor but the problem was too many people trying to make calls, not mechanical damage to the system, said Linda Bonniksen, spokeswoman for Pacific Bell.

“Everyone picks up the phone and we get heavy network congestion,” said Bonniksen. “It happens after every earthquake.”

There were no reports of problems with any Metrolink trains or stations, said Peter Hidalgo, Metrolink spokesman. Because the temblor was less than a 5.0, “there will be no significant evaluation of the rail system.”

“Only when it is 5.0 will all trains cease and all our inspectors inspect the entire 346-mile network, which takes about three hours to do,” he said.

Two late evening trains, one traveling from Los Angeles to Santa Clarita, and the other from Los Angeles to San Bernardino, continued with no delays. Southern Pacific Railroad officials also reported no problems or delays in their schedule.

Burbank Airport reported no interference with normal operations.

Times staff writer Jocelyn Stewart contributed to this story.