4.1 Aftershock of Landers Quake Follows Pattern North of Barstow

Another moderate aftershock of the June 28 Landers earthquake has been felt northeast of Barstow, an area that has been struck by more than 500 earthquakes since the big temblor.

Records show that 81 of the Barstow-area aftershocks were at least magnitude 3.0, and 10 of them had a magnitude of 4.0 or stronger.

The 4.1 jolt Tuesday night was centered 10 miles outside Barstow, and occurred as the weekly Southern California quake report by Caltech and the U.S. Geological Survey noted that aftershocks have been continuing north of Barstow while tailing off south of Yucca Valley.

Thomas H. Heaton, of the Geological Survey, said Wednesday that the cluster of aftershocks near Barstow is “clearly a striking feature” of the Landers quake. “We really don’t have much experience with this type of sequence, whether it will ultimately decay with time and turn off, or whether there will be some significant-size earthquake there,” he said.

Caltech seismologist Egill Hauksson noted, however, that the Barstow aftershocks are occurring at a shallower underground level than other aftershocks in the region, and they are somewhat reminiscent of a 1979 sequence of quakes in nearby Homestead Valley. Those quakes tapered off without a big temblor. The strongest Barstow aftershock has been 4.7.

Tuesday night’s temblor shook items off shelves in Yermo east of Barstow, but otherwise did little damage.