University Times

The University of Pittsburgh is on the move. Literally.

In the last year alone, the Oakland campus has drifted westward 1.69 centimeters.

At that rate, Pitt would travel almost 17 kilometers — for the metrically challenged, that’s about 10.8 miles — over the next 1 million years, calculates Bill Harbert, an associate professor and chairperson of Pitt’s Department of Geology and Planetary Sciences.

Harbert got the University’s drift thanks to a sophisticated global positioning system (GPS) installed last summer atop the Learning Research and Development Center (LRDC) building as part of a collaborative project involving Harbert’s department, the Pennsylvania Department of Transportation (PennDOT) and the National Geodetic Survey, among other organizations.

The LRDC building now is the most accurately determined position in southwestern Pennsylvania, according to Harbert. He and his colleagues have determined the location of the LRDC rooftop to be at:

• 40 degrees, 26 minutes and 40.28437 seconds latitude.

• 79 degrees, 57 minutes and 32.1190 seconds longitude.

• 312.473 meters above sea level.

LRDC was chosen after Harbert and his colleagues had considered but then rejected the rooftops of several other Pitt buildings, including the Cathedral of Learning (too unstable; the skyscraper sways slightly in the wind), Benedum Hall (rejected because the impressive top section of that facility actually is detached from the rest of the building), the Chevron Science Center (too tall and, therefore, of suspect stability) and the Space Research Coordination Center (shorter than its neighboring buildings and, so, not a good place to receive satellite signals).

“It was like Goldilocks finding the porridge that was just the right temperature,” says Harbert. “LRDC wasn’t too tall, yet it stands above almost all of the surrounding buildings.” Luckily, too, a pre-existing TV conduit through LRDC’s roof meant that Harbert and his colleagues didn’t have to drill any new holes, reducing the project’s costs. PennDOT is the main funding source, having paid $30,000 for computing equipment, coaxial cable and the GPS antenna and electronics.

The GPS site atop LRDC is part of an expanding network of continuously operating reference stations that provide GPS measurements in support of three-dimensional positioning activities throughout the United States and its territories. The network is coordinated by the National Geodetic Survey, an office of the federal National Oceanic and Atmospheric Administration.

Scientists, surveyors, en-gineers and others use the network’s highly accurate data in their work. So, too, will Pitt undergrads and graduate students, says Harbert.

“The thing about this project that is the most exciting to me is that we will be introducing this technology in our classrooms. It’s a great pedagogical tool. The accuracy that we have with this station [atop LRDC] is such that if we look at about four hours worth of data, our students will be able to determine a position to an accuracy of about 4 centimeters. If we get 12 hours worth of data — and the nice thing is that this site is continuously operating and recording data — the students will be able to determine a location to within 2 centimeters, or about the size of a penny.

“Just to be able to plug into that kind of technology should be exciting for our students,” Harbert says. “Learning to work with this technology also should make them more employable. GPS technology, geographical information systems technology and remote sensing technologies are extremely relevant to a wide variety of careers.”

Civilian use of global positioning technology, including the use of portable GPS receivers in recreational vehicles and by fishermen, hunters, campers and others already represents a $3.8 billion a year market, according to the National Oceanic and Atmospheric Administration. Integration of GPS into cellular telephones is expected to generate a huge volume of additional business, the administration says.

Harbert attributes the drift of the LRDC building (and, therefore, the rest of the Oakland campus) to the drift of the North American tectonic plate on which Pittsburgh and most of the rest of the United States sits.

The 1.69 centimeter-per-year velocity of the North American plate’s westward drift is slow by world tectonic standards, Harbert notes. He adds, comfortingly, that Pitt is located in a seismically low-risk area. “We’re safe not only from earthquakes but also volcanoes and tsunamis,” he says. “We do occasionally have small earthquakes in this area, but they’re related to the loss of glacial ice to our north. These quakes are usually quite minor, maybe on a magnitude of a 4 on the Richter scale.”

The seismic danger zone closest to Pitt is the New Madrid fault zone, located in the Mississippi River valley between Arkansas and Tennessee, the scene of two colossal quakes in 1811 and 1812. “It turns out,” Harbert says, “that modern engineering standards in our area take into account the possibility of a significant earthquake occurring in that area.”

— Bruce Steele