North Korea apparently failed to achieve desired explosiveness in its second nuclear test, a Yale University professor says, citing seismic readings that have been generated by it.
North Korea set off an underground nuclear explosion on Monday, creating a shock that registered 4.52 in magnitude on the Richter scale, according to a Vienna-based anti-nuclear weapons organization.
North Korea produced a magnitude of 4.1 in its first test in October 2006, the Comprehensive Nuclear-Test-Ban Treaty says.
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Jefferey Park, director of the Yale Institute for Biospheric Studies, said the seismic data from Monday's test indicate that North Korea failed to create a "Hiroshima-class crude explosive device."
"It was too small," he wrote on the Bulletin of the Atomic Scientists, referring to the explosion.
