Seismic readings point to small nuke test

RESTON, Va., May 26 (UPI) -- Seismic readings of the underground blast in North Korea were consistent with a small nuclear test, U.S. and international scientific organizations said.

However, the organizations said it could take days or weeks to determine whether the underground blast was a nuclear detonation and how successful it may have been, The New York Times reported Tuesday.

The U.S. Geological Survey in Reston, Va., said Monday's seismic event had a magnitude of 4.7, making it slightly larger than the one that the North Koreans generated in October 2006.

"Was it another fizzle?" We'll have to wait for more analysis of the seismic data, but so far the early news media reports about a 'Hiroshima-size' nuclear explosion seem to be overblown," Hans M. Kristensen of the Federation of American Scientists told the Times.

The bombs dropped on Hiroshima and Nagasaki had explosive yields of 15 kilotons and 22 kilotons, officials said.

Annika Thunborg, a spokeswoman with the Comprehensive Nuclear Test Ban Treaty Organization in Vienna, told the Times 39 of the organization's tracking stations detected the event, and the commission judged its magnitude to be 4.5.

U.S. officials said they haven't seen results of environmental sampling that might reveal details of the blast and confirm that it was nuclear.

"We know there was a seismic event of about 4.7, which comports with a nuclear test as the North Koreans have claimed -- and with what we had been anticipating them to do," a senior military officer said. "So it fits with their rhetoric and our expectations. But for any detailed assessment beyond that, we'll have to wait a few days for the tests and analysis."