Quakes rattle nerves Sixth tremor is measured in Columbia area

March 18, 1993|By James M. Coram and Douglas Birch | James M. Coram and Douglas Birch,Staff Writers

The shocks many Columbia residents are feeling after a series of minor earthquakes this week appear to be mostly psychological.

If the electricity goes off or the gas is leaking, people want to

know if it was caused by an earthquake.

For the record, the gas leak reported yesterday in a pipe at the John's Hopkins University's Applied Physics Laboratory, a one-minute power outage in the Village of Wilde Lake and an electrical fire in a transformer in an Owen Brown business park were not related to the quakes.

Damage could occur as a result of the small earthquakes Columbia has been experiencing, "but it's unlikely," said seismologist John G. Armbruster. To do that kind damage, an earthquake would probably have to register 4.0 or more on the Richter scale, 100 times greater than anything Columbia has experienced so far, Mr. Armbruster said.

Mr. Armbruster and fellow seismologist Leonardo Seeber came to Columbia from New York Monday night to set up earthquake monitoring equipment at seven Columbia locations. Both are research scientists at Columbia University's Lamont Doherty Earth Observatory in Palisades, N.Y.

Yesterday, they found that Howard County is continuing to quiver, recording what may have been the area's sixth and smallest earthquake in eight days. It was a barely perceptible tremor at 6:52 a.m. that registered just 1.0 on the Richter scale.

"It was about like someone falling out of bed nearby, I guess," said Dr. James P. Reger of the Maryland Geological Survey. "Hardly that."

The Lamont Doherty seismologists found that Columbia was shaken by two earthquakes Tuesday, not one as previously reported. A 3 a.m. shock registered between 1.0 and 2.0 on the Richter scale.

Kelvin Ramsey of the Delaware Geological Survey said that one of three instruments in that state also picked up what appears to have been another 1.0-to-2.0 quake at 11:59 a.m. Mr. Reger said the quake appeared to be centered in the Allview Estates section of Columbia.

"I know people's nerves are getting a little frayed because this is new to them," Mr. Reger said. "Someone from Los Angeles might laugh at us for being concerned about a little 2.5 earthquake."

"We don't know whether the activity is diminishing," said Dr. Klaus Jacob of Columbia University's Lamont-Doherty Earth Observatory. "That's an inference that we ought not to make. This [activity] may have been going on for weeks unnoticed and just culminated in these magnitude 2 earthquakes over the past two weeks."

"One a day is enough to make it interesting," Mr. Armbruster said, "but it is still not a lot." If the earthquakes continue at the same rate, he and Mr. Seeber should be here about two weeks, he said.

Meanwhile, the Howard County government has set up an earthquake information hot line -- 313-4461 -- and plans nightly earthquake updates and earthquake preparedness tips at 7:30 on Cable 15, the county government channel. Hot line callers will receive a 20-second message from Battalion Chief Donald R. Howell of the county fire and rescue service.

The message will be updated each morning -- more often if an earthquake occurs. When an earthquake is confirmed, the message will give its location, magnitude, time and date.

Since the earthquakes began, the county's emergency 911 line has received almost 2,000 calls about them, Chief Howell said, none of which resulted in "a single fire, rescue or emergency response." He is asking residents to use the 911 number for emergencies only.

Insurance companies are reporting what one agent said were "gobs and gobs of calls" about earthquake coverage. "Earth movement is excluded on the normal policy," said Allstate agent Rick O'Brien.

Since the quakes began, he has been receiving 15 to 20 calls a day inquiring about earthquake coverage, and most people who call are adding it, he said. Agents at five other companies tell a similar story.

They said costs range from as little as $14 a year to provide earthquake insurance on the contents of a condominium to more than $300 a year for people who live in masonry houses.

COLUMBIA QUAKES

1. Wednesday, March 10 9:32 a.m. 2.5 on Richter scale

2. Thursday, March 11 7:54 p.m. 2.0

3. Sunday, March 14 11:30 p.m. 2.7

4. Tuesday, March 16 3 a.m. 1.0-2.0

5. Tuesday, March 16 11:59 a.m. 1.0-2.0

6. Wednesday, March 17 6:52 a.m. About 1.0

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