Seismograph detects tremors in Pennsylvania

Scientists in Pitt’s Allegheny Observatory discovered earthquake activity in the region,… Scientists in Pitt’s Allegheny Observatory discovered earthquake activity in the region, thanks in part to a new seismograph.

While people in southwestern Pennsylvania might not think of the region as a seismically active area, a new seismograph captured evidence of constant earthquakes too small for people to feel.

William Harbert, a professor in Pitt’s department of geology and planetary sciences, said the new seismograph is sensitive enough to record earthquakes within 124 miles of Pittsburgh, which previous equipment could not detect.

Pitt and Penn State maintain the state-funded seismograph, which is located in the North Side. It is part of a nationwide effort between several universities called the Incorporated Research Institutions for Seismology, or IRIS.

The group maps out seismic activity across the nation in hopes of developing a better understanding of Earth’s internal structure.

Though not as seismically active as other parts of the nation, the Pittsburgh machine fills a gap in the network. It can pick up seismic activity from thousands of miles away.

Harbert said that soon after the seismograph was installed it detected a 6.2 magnitude earthquake in Alaska, nearly 4,000 miles away from Pittsburgh.

“Pitt’s station fills a data gap and places us in a group of universities and institutions responsible for providing the accounts seismologists need to know how seismic activity in one area of the world resonates everywhere,” he said.

Harbert compared the network sonogram, which takes images of the inside of a person.

“With a sonogram, you essentially have a vibrating source and a receiver that takes a picture inside of the person,” he said. “Imagine instead you have one source and hundreds of receivers.”

This seismograph is not the first one at Pitt. Workers built a seismograph into the Cathedral when it was under construction, but took it out for the 1950s.

The new seismograph, located on the North Side, is directly connected to the Internet and sends its data over the Realtime and U.S.=regional networks to the center of IRIS, in Seattle. It does this with one one-hundredth of a second of latency, allowing for unprecedented real time mapping of seismic activity in the United States, Harbert said.

“One thing your generation is benefitting from is incredibly dense network,” he added.

Harbert said the seismograph is also capable of recording events that might impact the region such as storm activity, man-made events caused by sequestering carbon underground or pumping water underground to retrieve natural gas.

Harbert said that between coal and natural gas mining, “Pennsylvania is going through a revolution in terms of energy production.”

This makes it even more important to be able to detect the impact of seismic activity and other events, he said.

“There are questions we can answer from, ‘How many small earthquakes have occurred in this area,’ … to whether we’ll create small earthquakes by pumping carbon into the ground,” he said. “There is so much we can learn about our region from this.”

The seismograph will also be used as an educational aid. Harbert plans to use the data in his classes to help students learn how scientists determine the location and magnitude of earthquakes.

He said he also hopes the Carnegie Museum of Natural History will display some of the seismographs’ data.