Quake Jangles Nerves but Does Little Damage : 31 People Treated for Mostly Minor Injuries in Tremor Put at 5.0 by Caltech, 4.7 by U.S. Agency

A moderately strong earthquake, an aftershock of the Oct. 1 Whittier Narrows temblor, shook the Los Angeles area Thursday morning, sending at least 31 people to hospitals with mainly minor injuries.

Nerves were jangled throughout the metropolitan area, but physical damage was slight. Skyscrapers and lesser structures swayed, but only a few windows shattered.

Authorities attributed no fatalities to Thursday’s quake, which struck at 7:25 a.m and was centered about 10 miles east of downtown Los Angeles in the Rosemead-El Monte area. But they noted that a 57-year-old Hacienda Heights man suffered a fatal heart attack during the quake.

The quake was measured at 5.0 on the Richter scale at Caltech’s seismology lab and at 4.7 at the U.S. Geological Survey’s earthquake center at Golden, Colo. Such differences are often attributed to distance from the quake and to varying interpretations of preliminary readings.

The readings mean that Thursday’s quake was about 10 times less powerful than the Oct. 1 shaker, which measured 5.9 on the Richter scale. That quake claimed three lives and caused more than $350 million in property damage.

Since the bigger quake jolted the Los Angeles Basin more than four months ago, there have been hundreds of aftershocks attributed to it--most of them too small to feel. Thursday’s was the second-largest--one of a group of 35 aftershocks to register more than 3.0 on the Richter scale.

The largest aftershock, which measured 5.3, was recorded three days after the original quake, and its epicenter was very close to the epicenter of Thursday’s quake, said Caltech spokesman Hall Daily.

No significant structural damage was reported in Thursday’s quake, said James Alexander of the state Office of Emergency Services. Minor damage--chiefly broken windows, objects falling off shelves and cracked chimneys--was concentrated in eastern Los Angeles and Orange counties, chiefly in El Monte, Pico Rivera, Whittier, La Puente, Montebello, Santa Ana, Buena Park and Fullerton.

The only damage reported to officials in the city of Los Angeles was one broken water main and one cracked chimney.

Lasted at Least 15 Seconds

But the quake, which lasted at least 15 seconds, was strong enough to set off burglar and car alarms and sway buildings through much of the metropolitan area.

It was felt as far south as San Diego and as far east as Palm Springs.

About 26,000 customers on Los Angeles’ Eastside were without electricity for about a minute because of a quake-triggered malfunction in a receiving station, the city’s Department of Water and Power reported.

Nearly 30,000 customers of GTE in the Rio Hondo area and Diamond Bar lost telephone service for as long as an hour.

The only reported victim of a heart attack during the quake, Sam Deville, was pronounced dead at Queen of the Valley Hospital in West Covina a little more than an hour after the temblor, a hospital spokeswoman said.

Five other people were treated and released at that hospital, including two who were admitted briefly for observation--one suffering chest pains and the other a pregnant woman who had fallen and suffered abdominal pain.

At Presbyterian Intercommunity Hospital in Whittier where 21 people were treated, spokeswoman Maria Adams reported that a majority were “injured by their own response to the earthquake rather than by the earthquake itself.”

“They panicked,” Adams said.

She said some ran and tripped, spraining ankles. Others suffered cuts from broken glass.

Two women were admitted to the hospital: Jennie Miraula, 87, suffering from chest pains, and Marjorie Simons, 64, with fractured vertebrae.

‘I Was on the Floor’

“I was taking a dish from the dining room to the kitchen, and the next thing I knew I was on the floor,” Simons told the Associated Press.

At Pomona Valley Community Hospital, two people were treated for minor injuries, including one who apparently jumped from a ladder during the earthquake, officials said.

In Anaheim, three people were treated and released for minor injuries at Humana Hospital West and Martin Luther Hospital.

Nerves seemed particularly frayed in the business district of Whittier, the area hardest hit by the Oct. 1 quake. The main street there, Greenleaf Avenue, still looks like a gap-toothed youngster, with an average of one building demolished on every block because of structural damage.

Earthquake repairs are obvious everywhere.

John Long, who moved to Whittier shortly before the Oct. 1 temblor, remarked: “Everywhere I go, I wonder what I should do when an earthquake hits and plan what table to jump under.”

Rebecca Gutierrez, a Whittier nurse on her way to work, said her 9-year-old son has been sleepwalking since the earlier quake. Thursday morning, she said, “he flew to me and grabbed me and was holding on to me like you wouldn’t believe.”

Seismologists said Thursday’s jolt was the largest in what they termed a “resurgence” of aftershock activity that began Christmas Eve.

Between Nov. 10 and Dec. 24, there had been no aftershocks as powerful as magnitude 2, a quake that can barely be felt, the seismologists said. But on Christmas Eve there was a 2.5 aftershock, followed by a 3.2 jolt on Jan. 2 and a 4.0 on Jan. 19. There have been 15 aftershocks of at least magnitude 2 since Jan. 2.

Caltech seismologists Clarence Allen said the “resurgence of aftershock activity . . . is unusual, but there is no such thing as a typical aftershock sequence.”

Times staff writers Sue Avery, Mary Lou Fulton, Nieson Himmel, Bob James, Carlos Lozano, Kenneth Reich, Jill Stewart and Tracy Wood contributed to this article.

THE QUAKE

RICHTER SCALE READING: 5.0

WHEN: 7:25 a.m.

EPICENTER: The Whittier Narrows area, site of the Oct. 1 quake that measured 5.9 on the Richter scale.

BREADTH: The quake was felt from as far south as Fallbrook in San Diego County, as far north as the Mojave Desert, as far east as Barstow.