Quake Monitor Installation Nears Completion in North Dakota

Installation is nearly complete on a network of earthquake-detecting instruments being placed across North Dakota as part of a national project, officials say.

Fred Anderson, a geologist with the state Geological Survey in Bismarck, said about 30 seismometers have been installed in North Dakota state since late 2008. The remainder will be installed in the eastern part of the state by the end of the month, at Grafton, Northwood, Oriska, Fort Ransom, Argusville and Colfax, he said.

Seismometers near Westby in northwest North Dakota and near Maddock in the north central part of the state were the first to be installed and have recorded one low-level earthquake each, Anderson said. The seismometers have not detected any tremors this year in North Dakota, he said.

The National Science Foundation’s EarthScope project will cover the entire U.S. with sensors, said Bob Woodward, a project director in Washington, D.C. The project was launched in 2003 and will wrap up in 2013.

“We’re passing instruments across the country to get a complete picture of what’s under the county,” Woodward said. “North Dakota is one of the lower seismicity areas of the country.”

The seismometers in North Dakota are among 400 in place at a time across the U.S., Woodward said. The sensors are moved after two years to another location as the project moves east.

Woodward said the national project has an annual budget of about $9 million.

The solar-powered instruments are buried about six feet underground, inside a 3-foot diameter plastic pipe, Woodward said. Data is transmitted to centers in Seattle and San Diego for use by researchers.

About 1,600 sites across the country have been chosen for the project, and instruments have been placed at about 950 locations so far, Woodward said.

The Dakotas marked the project’s halfway point, he said.

North Dakota’s only earthquake to be felt by people struck the state on July 8, 1968. Its epicenter was reported southwest of Huff, near Bismarck, and the quake was felt over a 3,000-square-mile area, Anderson said.

The seismometer near Maddock will remain in place permanently, Anderson said. North Dakota was one of the last states without a permanent facility, Woodward said.

Online: EarthScope: www.earthscope.org; Earthquake project: http://www.iris.edu/USArray/