Martin devices use sonar technology


October 18, 1990|By Ted Shelsby

To engineers at Martin Marietta Corp.'s plant in Glen Burnie, there is not a big difference between tracking Soviet submarines in the North Atlantic and predicting earthquakes similar to the one that rocked San Francisco a year ago yesterday.

Workers at the aerospace and defense contractor's Ocean Systems Operations are taking the technology for producing the underwater towed-sonar arrays used to detect enemy submarines and using it to develop new equipment that they hope will lead to early quake warnings.

The new electrical units, called IRIS, mark the first major upgrading of seismic equipment in the past decade, said Gordon Cumming, program manager of the Anne Arundel County plant's global seismographic network project.

The electrical units, placed underground to listen to the creaking earth and transmit signals to scientists, are expected to remain the state-of-the-art equipment for the next 25 years, he added.

"The hope is that by detecting minute shifts in the earth, we will have some predictability of earthquakes," said Albert Kamhi, a spokesman for Martin. "We need to get these units into the field and get the data back. Maybe it will offer a three-hour warning of an earthquake."

"We're talking about lives being saved. It may not save buildings, but it can save lives. That's the good thing to come out of this development. This is a good example of defense research being used for the public good."

IRIS is a "very major advance" in technology over previous seismic equipment, said Rhett G. Butler, with the Incorporated Research Institutions for Seismology, a consortium of 71 universities with graduate programs in seismology that is buying the equipment from Martin.

Mr. Butler compared the IRIS equipment with a home stereo recording unit that could pick up the very faintest sounds, the loudest sounds and the highest frequencies.

Mr. Kamhi explained that IRIS hears and records all the noise of a shift in the layers of the earth in much the same manner as compact discs can capture the sounds of all the instruments in an orchestra.

He said IRIS, unlike earlier equipment, has the ability to detect and record the sizable spread between very small seismic signals and extremely large ones.

Martin officials say the new equipment will also allow scientists to instantly detect a very small tremor in the presence of a large one simultaneously and in different geographic areas. With the old equipment, the sounds of the smaller tremors would be drowned out by those of the larger ones.

According to Mr. Kamhi, a single IRIS unit could register simultaneously a quake in Northern California and a slight tremor as far away as St. Louis.

Martin expects to build about 100 IRIS systems for the university group and other potential international customers. Units already have been shipped the U.S. Geological Survey's main seismic listening station in Albuquerque, N.M., and to other locations, including Alaska, New Zealand, Australia, Turkey and Norway.

The units, which sell for about $100,000 each, also can be used to monitor underground nuclear testing in the Soviet Union.

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