The quake, which was said to have occurred at approximately 03:48 local time, took place at a depth of nearly 16km (10 miles) in the sea west of the Korean peninsula – just days after North Korea threatened to carry out a “new form” of nuclear test.
While North Korean nuclear tests have previously been detected by the USGS quake monitoring center, the location and depth of the earthquake did not immediately suggest North Korean nuclear testing was the cause.
Although its December 2012 test M5.1 shockwave was similar in size to Tuesday’s 5.0M event, it was detected by geological surveys in China and the US as having occurred in a North Korean mountain range well known for weapons testing, and at a depth of only 1km.
On Sunday, North Korea threatened to carry out a “new form” of nuclear test, but did not clarify what it meant. Since then some observers have suggested that, angry with recent United Nations Security Council discussions about missile testing last week, Pyongyang may test a fourth nuclear device in the coming months.
On Monday, the two Koreas fired hundreds of rounds of artillery into waters along the disputed Northern Limit Line.
North Korea warned its southern neighbour at short-notice that it would commence the live fire drills, which some analysts said was Pyongyang’s way of protesting ongoing joint US – South Korea military drills.
Previously, North Korea has also warned its neighbours of impeding nuclear tests, usually also at short-notice. – Telegraph.