A day after North Korea said it tested a nuclear device and seismic sensors worldwide registered tremors consistent with a small test, the question remains: What exactly happened at that mountain site near the Chinese border?
Many scientists and most governments concerned have yet to definitively conclude whether it was a small nuclear device, a dud test of what might have been a much larger device or even a non-nuclear explosion.
”There is no clarity at all at the moment,” said defence analyst and physicist Andrew Davies from the government-funded Australian Strategic Policy Institute (ASPI).
In South Korea, the presidential spokesperson quoted chief national security adviser Song Min-soon as saying: ”It will take about two weeks to make a comprehensive assessment.”
Foreign Minister Taro Aso said Japan wanted ”proof that such a test took place” before weighing new sanctions on North Korea.
A United States official said it could take several days for intelligence analysts to determine what exactly happened, and China, while working on the assumption that the blast was nuclear, has offered no details.
Even the head of the preparatory commission for the Comprehensive Test Ban Treaty Organisation, which operates an international nuclear test monitoring system, seemed still to be sitting on the fence. In a statement Volodymyr Yelchenko expressed ”profound consternation at the announcement” of the test and urged Pyongyang not to ”engage in any nuclear testing”.
Russia, so far, is the only country to have come down decisively, saying it was definitely a nuclear test and it was between 5 and 15 kilotons.
Even the size of the nuclear test — or whatever it was — is in question, and the evidence has been inconclusive, requiring deeper analysis.
The US Geological Survey measured a 4,2-magnitude tremor in the northern part of North Korea on Monday at about 10.35am local time (1.35am GMT). Seismologists said that could be the result of a one-kiloton blast.
South Korea, meanwhile, reported the magnitude to be 3,58, which would mean it was an even smaller blast.
Neither seismic measure proves the blast was even nuclear, analysts say, and nobody has publicly reported radiation.
TNT explosion?
So, could North Korea have detonated 500-1 000 tonnes of TNT to simulate a nuclear explosion? The short answer is: yes.
”Essentially, if you had one kiloton of TNT and detonated it, it would generate the same sort of blast as a nuclear bomb,” said Chan Lung-sang, a seismologist at Hong Kong University.
But such a feat would be very difficult to achieve and the benefits questionable.
”By all appearances it seems that what they [North Korea] are saying is true, but everybody is being cautious about making unqualified statements until more data is processed,” said Robert Karniol of Jane’s Defence Weekly.
Whether it was intentionally a small nuclear blast or a dud that should have been much bigger is much tougher to answer.
If it was meant to be small, it would show a relatively high degree of sophistication and mean that North Korea might be approaching the capability of putting a nuclear device on a ballistic missile, analysts say.
If it was a dud, or a partial explosion, Pyongyang would still have learned a great deal from the test.
Even if North Korea blew up a few hundred tonnes of TNT, the geopolitical fallout would be the same.
”I can’t really see what difference it makes in terms of this broad understanding by the international community that the North Koreans have a number of nuclear weapons completed and have capabilities to build more,” Karniol said. – Reuters