Last modified: Wednesday, February 13, 2013
Indiana University quake detection experiment registers North Korean blast
FOR IMMEDIATE RELEASE
Feb. 13, 2013
BLOOMINGTON, Ind. -- An Indiana University geophysical experiment detected seismic signals from the reported nuclear device that North Korea detonated this week.
The experiment involves the deployment of up to 140 state-of-the-art seismographs across a broad swath of the Midwest, from Missouri through southern Illinois and Indiana, through western and central Kentucky. The experiment is part of a collaborative National Science Foundation project being carried out by researchers at IU Bloomington, Purdue University, the University of Illinois and the Indiana and Illinois geological surveys.
Michael Hamburger, professor in the Department of Geological Sciences in the IU College of Arts and Sciences, said some seismographs in the network detected the North Korean blast around 10:10 p.m. Monday, about 13 minutes after it was detonated.
"Seismic recordings such as these have been one of the most powerful tools for understanding the process of nuclear proliferation and underground nuclear testing," Hamburger said. "They are currently the primary tool for verification of nuclear testing treaties."
In the case of the North Korean explosion, the most critical measurements will come from seismic stations in the Asian-Pacific region, he said. The IU experiment -- known as OIINK for its location in the Ozarks, Illinois, Indiana and Kentucky -- picked up a P-wave signal from the explosion at detectors in Missouri. With an estimated strength equivalent to an earthquake of 5.1 on the Richter scale, the explosion was barely over the threshold for detection by the experiment.
North Korea announced Tuesday that it had tested a nuclear device, drawing widespread condemnation from other nations. The explosion was reportedly stronger than tests North Korea conducted in 2006 and 2009.
Seismographs in the IU experiment, while they are used to record and study earthquake activity, routinely register energy waves from countless small explosions at quarries and surface coal mines in the region. Distinguishing natural events such as earthquakes from artificial events such as explosions is a key research area of the science of seismology, Hamburger said.
The OIINK project will eventually position up to 140 seismometers to study earthquakes and geological structure in the region. Installation began last summer, and about 70 instruments are now in place and recording seismic activity.
The $1.3 million, four-year undertaking is part of the NSF's EarthScope program, which seeks to cover the entire U.S. with a grid of detection devices for the purpose of better understanding Earth structure and seismic activity in the North American continent.