|The North Korea flag flutters|
When the tremors were first reported earlier, China said it believed they may have been caused by an explosion.
But the country's earthquake monitoring centre later went on the say a magnitude 3.4 earthquake was not the result of a fresh missile test.
Lassino Zerbo, of nuclear watchdog the Comprehensive Test Ban Treaty Organisation (CTBTO), tweeted that the quake was not man-made but similar to a "collapse" event, or tremor, that followed almost immediately after the 3 September test.
|The tremor was detected near where North Korea recently conducted a nuclear test|
The tremor was detected near where North Korea recently conducted a nuclear test
The latest alert comes amid heightened tensions in the Korean peninsula.
On Friday, Donald Trump publicly branded the North Korean leader Kim Jong Un a "rocket man" and said American "really had no choice" but to confront the authoritarian regime.
|Trump on N Korea 'staggering'|
The site of the 3.4 tremor is close to where the regime claimed to have detonated a thermonuclear weapon on 3 September, in its sixth and most powerful nuclear test to date.
|New sanction order 'targets' North Korea|
Mr Kim branded the speech the "most ferocious declaration of war in history" and
said he would consider the "highest level of hardline countermeasure" in response.
Tens of thousands of people reportedly took part in an anti-America march in Pyongyang on Friday.
And US bombers and fighter jets have flown along the coast of North Korea in a show of force.