False Security On Earthquakes

April 10, 1994|By LEONARDO SEEBER

The Sun editorial entitled "Steady, Mr. Ecker" (March 8) gave the Howard County executive condescending advice about cluttering his mind and possibly burdening his taxpayers with the issue of earthquakes in Maryland. As the writer of the article in The Sun's Perspective section that apparently renewed Mr. Ecker's concern about earthquakes, I am disappointed by the editorial.

The first obvious issue is the probability of earthquakes in Howard County. States the editorial: "It's even possible that [earthquakes] will recur. It's just as likely, though, that further quakes . . . might never happen again in Howard County." Somebody didn't bother to check the data; according to the U.S. Geologic Survey's catalog, the state of Maryland has experienced one earthquake sequence, such as the one in Columbia in 1993, every 10 years or so. . . .

In fact, the above quote from the editorial was already proven wrong by history when it was written; the successor to the Columbia earthquake sequence a year ago has already occurred in October 1993 near Ellicott City. Is this seismic event related to the ones in Columbia? Where and how deep was the source? Did it have small aftershocks? Could it be part of an ongoing sequence? Could it have been triggered by artificial factors? Can we recognize a fault related to the earthquake? Not only we are not in a position to answer any of these questions, but we might have missed the earthquake altogether had the state of Delaware not been operating a small local seismic network. Likewise, without the intervention of neighbors and friends (i.e., our group from New York), the people of Maryland might have remained in the dark about the nature of the phenomena in Columbia last spring.

A question concerning hazard in Howard County is not whether earthquakes will occur; they will. But, rather, how big they can be and how often they are going to be in the size range where they cause damage. These fundamental questions concerning hazard are largely unanswerable now and they will remain so for some time, particularly if The Sun's editors convince a lot of readers that interest and concern about earthquakes in the East is misplaced.

Actually, the rate of seismicity in Maryland is substantially higher than portrayed in the USGS catalog. I know of at least as many earthquakes in Maryland that are not in the catalog -- chance findings while researching historical seismicity elsewhere. . . .

The editorial expresses outdated, overly optimistic assumptions about earthquake hazard in the East and misses one of the central points about earthquake hazard in "stable" continental areas: Mapped faults and historical seismicity are poor guides as lTC to the site of the next damaging earthquake. Not only were there no historical epicenters and no mapped faults near the epicenter of the killer earthquake in India last fall, but the fault rupture came to the surface in 65 million-year-old rock without any sign of a pre-existing fault. A sense of security based on the lack of mapped active faults in the eastern United States (or in any other tectonically "stable" continental areas) is equivalent to driving in a forest with eyes closed because the trees have no warning signs.

In January, a series of earthquakes centered about 60 miles north of Baltimore, near Reading, Pa. caused $2.6 million in damage. Small earthquakes at the same location occurred a half-year before and could have been interpreted as a warning sign had someone been interested in studying them. So, you don't have to go far from Howard County to find earthquake damage greater than the cost of an earthquake monitoring program.

A typical scientist capitalizing on fear to obtain research funds? Actually, I am much more interested in arguing that seismology should be pursued because earthquakes "are there," part of our precious and magnificent environment which we are endowed with the ability to enjoy by trying to understand it. If society finds it necessary to invest billions in convincing our kids to eat potato chips and to smoke cigarettes, in a display of hypocrisy, why should it not also invest in monitoring and in understanding what is happening in our natural environment, as a display of another aspect of humanity to inspire the next generations? Science and art can feed our spiritual hunger and provide an alternative to the boredom, loneliness and purposelessness which is likely to pervade a society totally dedicated to self-interest.

Leonardo Seeber is a seismologist at the Lamont-Doherty Earth Observatory of Columbia University.

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