Nuke tests may destroy mountain
NORTH Korea's nuclear testing may not lead to war, but there is another catastrophic risk: the mountain it has exploded six bombs under may collapse.
Hong Kong's South China Morning Post is quoting a Chinese scientist as saying if the peak crumbles, clouds of radioactive dust and gas will blanket the region.
The Punggye-ri test site is in the country's north-east and carved deep into the side of Mount Mantap - a granite peak in the remote Hamgyong mountain range.
Geophysicist Wen Lianxing's team at the University of Science and Technology of China have analysed data from more than 100 seismic monitoring sites across China, narrowing the location of the tests down with a margin of error of just 100m.
They've all been under the same mountain. And the weekend's blast was by far the biggest of them all.
It produced a shockwave similar to that of a magnitude 6.3 earthquake, indicating a bomb equivalent to 120 kilotonnes of TNT explosive.
Eight minutes later, a second quake was detected. Geophysicists around the world have been considering its implications.
So far the consensus is it was likely part of the mountain collapsing in on a cavern created where the rock was vaporised by the blast of the hydrogen bomb.
Satellite imagery also shows the blast caused numerous landslides around the Punggye-ri test site.
Radiation sampling in the region has so far returned no abnormal readings, but nuclear weapons researcher and chair of China Nuclear Society Wang Naiyantold the Morning Post such an event indicates a potential environmental disaster in the making.
One more test could cause the mountain to collapse in on itself, he warns.
"We call it 'taking the roof off'," Mr Wang said.
"If the mountain collapses and the hole is exposed, it will let out many bad things.
The tests "pose a huge threat not only to North Korea but to other countries."
Satellite photos taken just a day after the blast and released by 38 North reveal new gravel and scree fields shaken loose by the blasts.
Chances are, North Korea will continue to test at the Punggye-ri test site as it has few other suitable locations.
Nuclear testing requires a mountain of solid rock with a peak, but it must also have only gently sloping sides to reduce the risk of landslides. Another factor is whether North Korea has drilled vertically beneath the mountain before planting its bombs, or tunnelled horizontally into its heart.
Things may not be so dire if North Korea had expended the extra time and effort necessary to go deep, Wang says. But if it had simply drilled into the side of the mountain, this increased the risk of "blowing the top off".
North Korea has given no indication it intends to end its testing of hydrogen bomb warheads intended to be carried by its new inter-continental ballistic missiles.
A top North Korean diplomat has warned that his country is ready to send "more gift packages" to the United States as world powers struggle for a response to Pyongyang's latest nuclear weapons test.
North Korea's ambassador to the United Nations Han Tae-song declared the testing of its sixth and largest bomb to be a complete success.
"The recent self-defence measures by my country, DPRK, are a gift package addressed to none other than the US," Han told a disarmament conference.
"The US will receive more 'gift packages' ... as long as it relies on reckless provocations and futile attempts to put pressure on the DPRK."