Scientists Want to Study Possibility Human Activity May Have Triggered Quake Near Buffalo

BUFFALO, N.Y. -- An earthquake that shook Cuylerville, N.Y., a small town about an hour southeast of Buffalo, has geologists wondering what triggered it.

Centered near the largest salt mine in North America, the area where the March 12 earthquake was felt has experienced previous seismic activity. In 1929, a 5.2 earthquake was centered in nearby Attica, close to the Clarendon-Linden fault.

But a collapsed roof in the mine, about 100 stories beneath the earth's surface, and related fractures at the surface have raised scientists' suspicions that it was humans, not nature, that prompted the quake.

"The question of whether the recent collapse of a portion of the Akzo salt mine resulted from the earthquake, or induced it, has still not been resolved," said Robert Jacobi, Ph.D., associate professor of geology at the University at Buffalo.

"We have some evidence that points to a non-natural earthquake source for the Cuylerville event."

To find out just what triggered the quake, Jacobi and John Fountain, Ph.D., associate professor of geology at UB, along with Leonardo Seeber, a seismologist at Columbia University's Lamont-Doherty Earth Observatory, have proposed an investigation.

The research could shed light on the mechanism behind other earthquakes that also may have been triggered by human activity, such as the filling of valleys with water for dams, and salt or coal mining.

Jacobi added that the proposed studies also are necessary to determine how the mine, which has been closed since the temblor, could be reopened.

"Because water has been flowing into the mine at a rate of several thousand gallons per minute, and because dangerous levels of methane have been detected in the mine, more information is required in order to evaluate the most appropriate strategies to mitigate hazard," Jacobi said.

Earthquakes induced by human activity are not all that uncommon, Seeber said.

A recent example occurred in 1987 in Ashtabula, Ohio, where waste fluids were being disposed of in a deep well.

"There are many things that we do to the earth, such as creating reservoirs, drilling oil wells, or digging coal or iron out of mines as deep as a mile under the surface, that can weaken the earth's crust and trigger an earthquake," said Seeber.

He pointed out that old coal and iron mines are commonly found in the eastern and midwestern United States, particularly along the Appalachian Mountains.

"Since these mines and other manmade structures below the earth's surface are widespread occurrences, we should be studying their mechanical effects," he said.

A common practice in mines is to remove ore while leaving pillars as supports for the roof.

In Cuylerville, a 600-x-600-foot portion of the roof at the mine collapsed. The mine is about 1,000 feet deep at this location.

To determine whether the Cuylerville seismic event was natural or was due to the roof collapse, several types of studies are being proposed. The geologists want to determine exactly the area over which the earthquake was felt. They note that a rock collapse, like a landslide, tends to produce vibration at low frequencies, rather than the high frequencies that characterize earthquakes.

They will examine existing seismograph records to see if the seismic wave character is typical of natural seismic events, and they will study the fractures at the surface above the collapsed roof.

Fractures are of particular interest, Jacobi said, because they may be providing pathways for the gas and water to flow through. In Western New York, they are difficult to detect because there are not many rocks exposed.

Using a procedure developed by Fountain and Jacobi, the geologists hope to locate the fractures by studying the concentration of methane in the soil.

Other techniques that may be used include field mapping and remote sensing, including low-altitude infrared photography.