Pair of 4.7 Quakes Rattle Inland Area

Two moderate aftershocks from the June 28 Landers earthquake, both of 4.7 magnitude, rumbled beneath the Coachella Valley on Friday, jolting residents of Palm Springs and Indio but apparently causing no injuries or damage.

The first temblor, reported at 11:14 a.m., was centered about 14 miles northwest of Indio, said Heidi Aspaturian, a spokeswoman for the Caltech seismology laboratory in Pasadena.

The second hit at 9:32 p.m. and was centered 11 miles east of Desert Hot Springs--only two miles from the epicenter of an April 22 temblor, of 6.2 magnitude, that began the sequence that resulted in the Landers quake two months later.

Friday’s first aftershock, which lasted about 10 seconds, was felt in Los Angeles and San Diego, both about 100 miles from the epicenter.

“That places it in the southern end of the aftershock zone of the Landers quake,” Aspaturian said.

The June 28 Landers quake, which measured 7.5, was followed a few hours later by a magnitude 6.6 quake in Big Bear. Seismologists said the twin temblors have been followed by thousands of aftershocks, more than 20 of which have topped 4.0. The aftershocks are expected to continue for about a year.

Almost 600 homes have been destroyed and another 5,700 damaged in the twin quakes and their aftershocks so far, according to a report released Friday by the American Red Cross.

The Red Cross pointed out that even though a home may have suffered only minor damage in the initial quakes, aftershocks can increase that damage and render the structure uninhabitable.

The damage zone from the earlier quakes stretches from Twentynine Palms on the east to Riverside on the west, and from Barstow on the north to San Jacinto on the south.

In Big Bear City, 268 homes have been destroyed, 677 homes have sustained major damage and 996 are listed with minor damage. In Landers, 77 homes have been destroyed, 171 have sustained major damage and 110 have minor damage.

Friday’s aftershocks were not the only thing that rattled the residents of Landers.

Massive explosions set off as part of war games being conducted at the nearby Twentynine Palms Marine base have been triggering complaints from “a lot of people” made jittery by quakes, said Sgt. Tony Sinagra, a spokesman for the Marine Corps. The maneuvers will continue, Sinagra said.

“Marines come from all over the country to do their training here,” he said. “The bottom line is that we have to continue the training.”

Ruth Rendahl, executive director of the Yucca Valley Chamber of Commerce, said that when aerial bombing takes place at the Marine base, “we’ll stop and take a breath and ask: ‘Which is it?’ ”