5.4 Landers Aftershock Hits Barstow

A powerful aftershock of the 1992 Landers earthquake struck near Barstow on Tuesday, sending goods in some stores to the floor, collapsing a saloon wall at the Calico ghost town and shaking many other parts of Southern California.

No injuries were reported.

Caltech seismologists said the 7:24 a.m. temblor measured magnitude 5.4 and was centered on the Calico fault 12 miles northeast of Barstow in an area that has experienced a cluster of several thousand aftershocks over the last five years.

But this was the strongest jolt of the cluster, which is about 20 miles north of other areas of frequent aftershocks of the 7.3 Landers quake of June 28, 1992.

The Mojave Desert area most strongly shaken by Tuesday’s quake is about 100 miles northeast of Los Angeles, which felt only light tremors. It was also felt in Orange, San Bernardino and Riverside counties.

A Caltrans spokesman said inspectors found superficial cracks in two bridge support structures on freeways in the Barstow area, but were not sure whether they were caused by the earthquake or had existed before.

The hairline cracks, in bridge abutments, were about 2 1/2 inches long. They were found on Interstate 40 and Interstate 15, east of Barstow. Traffic was not affected.

But nearby, the Calico ghost town, a preserved 1881 mining town that is operated as a tourist attraction by San Bernardino County, was closed for the day for inspection.

Joe’s Saloon, heavily damaged in the original Landers quake and never repaired, lost another wall, said Calico spokesman Steve Nelson. “But a sneeze would have brought it down,” he added.

Sheriff’s Sgt. John Mattke said: “Several Calico buildings have what appear to be damage to the walls and the facades. It looks like cracks in the walls running from top to bottom.”

A cloud of dust rose over the epicenter of what scientists quickly named the Calico earthquake.

Renee Hanna, a resident of Barstow, mistook the earthquake for military maneuvers at nearby Ft. Irwin.

“I figured those silly Army guys were rockin’ and sockin’, so I ignored it,” she said. “My indoor palm trees were weaving and the windows shook, but I didn’t know it was an earthquake until I got in my car and turned on the news.”

Damage at stores in Barstow was fairly minimal.

Easter baskets fell from shelves at the local Wal-Mart and several dozen liquor bottles and other items were destroyed at the Thrifty drugstore on Barstow’s Main Street.

“I’ve got a lot of broken glass, things thrown off the shelves,” said Maggie Ariy, a clerk. “Quite a mess.”

Asad Jabbar, owner of Quick Liquor, said he lost about 20 bottles of liquor. Only canned goods, no bottles, fell at Vons.

Meanwhile, data from 60 recording instruments in the new TriNet seismographic network installed by Caltech, the U.S. Geological Survey and the California Division of Mines and Geology showed that the ground moved at a maximum rate of about two inches per second during the quake.

The fastest movement was recorded at Flash Peak, 13 miles west of the epicenter, showing that the direction of the rupture was westerly.

In a demonstration of the new system’s capability, a map of shaking intensities in all affected areas was made available at Caltech 10 minutes after the quake occurred.

Compared with the 1994 Northridge quake, the movements were small. Northridge ground velocities reached as high as six feet per second near its epicenter.

Seismologist Lucy Jones of the U.S. Geological Survey said there have been several 4.7 or 4.8 aftershocks near Barstow since the Landers temblor. The strongest previous shock in the Barstow cluster was a 4.8 on Aug. 5, 1992.

Although Tuesday’s jolt was five times stronger than that, she said, it was well within the normal range of what could be expected over an aftershock cycle that may last decades.

Jones also noted that there were at least three foreshocks to Tuesday’s temblor, a 2.9 at 1:47 a.m., a 1.9 at 2:04 a.m. and a 2.0 at 7:07 a.m.

Other shocks after the 5.4 quake included a 3.7 at 8:19 a.m., a 3.4 at 8:40 a.m., a 3.1 at 1:28 p.m. and a 3.3 at 8:45 p.m.

A statement by Caltech, the U.S. Geological Survey and the Southern California Earthquake Center at USC said two further aftershocks of magnitude 4 can be expected in the next week, and there is a probability of 5% to 10% that a larger quake than 5.4 will strike during that period.