The "artificial quake" in North Korea Sunday, thought to be its sixth nuclear test, was 9.8 times more powerful than the tremor from Pyongyang's fifth test, the South's Yonhap news agency reported citing the state weather agency.

It was "not only 9.8 times more powerful than the nuclear test conducted in September last year, but it is the most powerful", an official at the Korea Meteorological Administration told Yonhap.

Source: AFP