Newswise — Individuals may soon have an inexpensive way to learn of volcanic and earthquake activity from their home or business. Randall Peters, professor and chairman of the Department of Physics at Mercer University, and James Shirley, a scientist at NASA's Jet Propulsion Laboratory, have designed a sophisticated plumb bob device that records seismic waves from around the world. The inexpensive instrument, located in Macon, Ga., recorded the seismic waves from the December Indian Ocean earthquake that led to the devastating tsunami. From the arbitrarily assigned time zero at the start of the record, just before first disturbance, it is seen that the plumb bob moved at levels above background noise for a period of more than two hours.
These results point to the possibility of a 'volcanic eruption and earthquake detector for the masses.' It would be an instrument designed not to gather scientific data, but rather for the purpose of information that could have the potential to provide a personal early warning system. As envisioned, such an instrument would be both inexpensive and user friendly, yet capable of recording the larger earth events that precede a catastrophic tsunami or a volcanic eruption such as that of Mount St. Helens in 1980.
Although the mechanical function is analogous to a carpenter's plumb bob, used to insure that the walls of a building stand vertical; the other components of this instrument are high-technology. It was designed by Mercer Professor Peters in collaboration with Shirley of NASA, to test predictions made by a new theory involving gravity and inertial forces. Using a capacitive sensor patented by Peters, the instrument can detect ground movements three thousand times smaller than the thickness of a human hair (<25 nm). The largest amplitude of the motion in Macon due to the earthquake is estimated from data that yielded the record above and from the calibration constant of the instrument to be about two-thousandths of an inch, with a period of oscillation equal to 30 seconds.
Founded in 1833, Mercer University has campuses in Macon and Atlanta as well as three regional academic centers. With 10 schools and colleges, the University offers programs in liberal arts, business, engineering, education, medicine, nursing, pharmacy, law and theology. For 15 consecutive years, "U.S. News & World Report" has named Mercer University as one of the leading universities in the South.
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