VIRGINIA WELL SEES EVIDENCE OF ASIAN EARTHQUAKE

by Kaspel, Saturday, January 08, 2005, 18:19

By DIANE TENNANT, The Virginian-Pilot
© January 8, 2005

For anyone on the right Web site, the earthquake in Indonesia could be seen in the sudden rise and fall of water in a well at Christiansburg.

David Nelms, a groundwater specialist with the U.S. Geological Survey in Richmond, was in the right place at the right time.

“Right after Christmas, I was at home, looked at it on the Internet and said, “There it is,’ ” Nelms said on Friday. “It just shot up and then it went down below where it originally was.”

The USGS and the state Department of Environmental Quality has real-time monitors in 21 water wells throughout Virginia, mostly to keep track of drought. They can be viewed at http://va.water.usgs.gov.

The USGS calculated from the longitude and latitude of the earthquake, plus the longitude and latitude of the well, plus the speed of the seismic wave, which was about 7,400 mph , that the well should record the earthquake about an hour after it occurred. It did.

The water level changed by about 3 feet. It took about five hours to quit fluctuating, Nelms said.

The Christiansburg well â€" close to Blacksburg and Virginia Tech â€" used to be a municipal water supply. It is 450 feet deep, in limestone. Fractures in the rock allow water to flow through. As the earthquake squeezed and then relaxed the fractures, water moved in and out of the well.

It’s not unheard of for wells to be affected by distant earthquakes, but the Christiansburg well is particularly sensitive to movements in the Earth. No one is sure why.