A behemoth visits Holtville

May 18, 2002|By JENNIFER RALTON-SMITH, Staff Writer

Jokes about 800-pound gorillas aside, Pine School principal Cathy Denton was remarkably poised Thursday morning as she watched a lumbering 555,000-pound behemoth rapidly approaching as she stood her ground on the school's football field.

The small country school north of Holtville was about to play host for the day to a gaggle of clever people and their very big machine.

With U.S. Geological Survey geophysicist Ron Porcella by her side, Denton summed up the situation nicely by asking, "Basically, you're going to shake the ground, right?"

That's exactly what Porcella, Professor Kenneth Stokoe of the University of Texas at Austin and a bunch of doctorate types from the university's civil engineering department were going to do.


"The USGS operates permanent earthquake monitoring stations around the nation and here in the Imperial Valley we've got 26 stations from the Salton Sea down to Calexico," Porcella explained, smiling almost apologetically as he admitted that, "Imperial Valley is basically a great big laboratory for us."

Porcella installed one of those monitoring stations himself 20 years ago at Pine School and now he was back with the university staff so they could collect data using a unique method.

The "behemoth" was actually equipment used by the oil exploration industry and had been brought from Midland, Texas, to simulate earthquake activity so the professor and his team could gather data used by the engineering community nationwide.

As Stokoe explained, "Architects and engineers need this data when they design buildings, dams, bridges, power stations. They want to know exactly how the ground vibrates during an earthquake."

The machine, called a Vibroseis, sends heavy vibrations through the upper portion of the earth's surface over a given area and by measuring the distance and velocity of those vibrations, oil exploration scientists are able to determine if oil deposits are present.

And what could be more irresistible to a bunch of school kids than a huge machine shaking the earth?

Principal Denton allowed the entire student body to swing by the football field to check out the action and the general consensus was a chorus of, "Gee, that's awesome!" as the kids filed by.

Porcella, ever the earthquake devotee, recommends a visit to the USGS Web site and its "shake maps" that load onto the Web site minutes after the earth has a temper tantrum. The site has links to other sites and a host of information on Mother Nature's other tantrums — volcanoes and floods. Porcella said it's a great site for kids to visit.

>> On the web:

>> Staff Writer Jennifer Ralton-Smith can be reached at 3373442 or

Imperial Valley Press Online Articles