Mercer Professor Invents Earthquake Detector
January 12, 2005

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Posted in The Macon Telegraph on Wednesday, Jan. 12, 2005



Telegraph Staff Writer

Almost by accident, a Mercer University professor invented an instrument that may lead to an inexpensive early-warning device for earthquakes, volcanic eruptions and tsunamis for use in homes or businesses.

Professor and physics department chairman Randall D. Peters discovered the new use for his device when it recorded, from the basement of his Macon home, the Dec. 26 earthquake that caused the tsunami in the Indian Ocean.

"Before I ever heard anything on the news, I retrieved the data and there was this huge disturbance," Peters said.

Peters said he wants to produce the most sophisticated, mass-marketable seismograph on the market as cheaply as possible.

His device is similar to a carpenter's plumb bob, which is used to make sure walls are vertical. It is basically a pendulum on a string with sensors on either side that measure minute oscillations caused by movement in the Earth's crust.

It is 6 inches long by 6 inches wide and stands 30 inches tall, but could be produced much smaller, he said.

Peters and James Shirley, a scientist at NASA's Jet Propulsion Laboratory, constructed the instrument for use in an experiment to test a new theory involving gravity and inertial forces.

Peters said his instrument could be converted to private use simply by adding a $15 computer chip. With this chip, Peters said, his earthquake forecaster could sell for $100.

No one currently mass produces this chip because there is no market for it. However, Peters said a Japanese firm capable of manufacturing one is interested in pursuing his idea. Personal seismometers, instruments for measuring movement in the Earth's crust, sell for between $50 and $300, said Georgia Tech geophysics professor Tim Long. The most expensive research systems range between $2,500 and $4,000.

"When you make a good sensor, you can detect 6.0-magnitude earthquakes anywhere in the world," Long said.

Long said he got a nice recording of the Indian Ocean earthquake with his own seismograph in north Georgia.

Even though he scavenged the parts for his machine from other experiments, Peters said they are all fairly standard industrial materials.

Peters said his instrument offers two advantages over the latest generation of seismographic equipment. First, it has extremely sensitive sensors, for which Peters holds a U.S. patent, to measure the pendulum's movement. In building the device, Peters said he paid special attention to the physics of the components.

"The key to performance is the quality of the components, in which there is a lot of physics that is being ignored," Peters said.

Second, it also records the higher frequencies that travel along the Earth's surface after an earthquake.

"People are killing themselves trying to get lower frequencies when my instrument is more than capable of the work," Peters said. "It takes thinking outside the box."

The instrument is capable of recording ground movements 3,000 times smaller than the thickness of a human hair, Peters said.

The key to all seismographs is trying to keep the pendulum still, said Peters. He has one sitting on the windowsill of his office that he said, were it in Sumatra, could have saved lives.

"The simplicity of this thing is what makes it so important," Peters said. "I opted for the simplest possible mechanics."


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