North Korea's nuclear tests have damaged Earth's crust, caused tremors months later

Two tremors detected in North Korea yesterday were likely to be aftershocks from the hermit nation's reckless nuclear test in early September, a US Geological Survey official confirmed.

The mild 2.9 and 2.4 magnitude aftershocks were confirmed as "tectonic" in origin by the Vienna-based Comprehensive Nuclear-Test-Ban Treaty executive secretary Lassina Zerbo.

The USGS official claimed the tremors originated near the Punggye-ri nuclear test site - the location where North Korea carried out its largest nuclear test to date on September 3.

The official said: "They're probably relaxation events from the sixth nuclear test. When you have a large nuclear test, it moves the Earth's crust around the area, and it takes a while for it to fully subside.

"We've had a few of them since the sixth nuclear test."

North Korea claimed its September test was an H-bomb - with experts estimating it was 10 times more powerful than the US atomic bomb which was dropped on Hiroshima in 1945.

A sequence of tremors since that test has led experts to believe that there was damage caused to the mountainous region in the north-west of the country.

Last month it was claimed that 100 workers were feared at the site had been trapped after the tunnel reportedly collapsed on September 10, although this has not been confirmed.

In October, South Korea's spy agency said it believed Pyongyang might be readying two more tunnel at the site.

One obstacle which could scupper North Korea using the Punggye-ri test is the nearby active volcano Mount Paektu, which is considered a sacred site by the communist nation.

The dictator paid a visit to the site yesterday, which is claimed to be the birthplace of the secretive state's first dictator, Kim's grandfather.

Pictures released by the regime show the Kim in the snow at the 9022ft, on North Korea's border with China, which the regime rewrote history to claim was birthplace of Kim Il-Sung, the Communist who ruled from after the Second World War until 1994.

He was in fact born near Pyongyang in 1912, but the mountain has long been integral to the country's identity.