The mountain visibly shifted following the largest detonation which caused a 6.3 magnitude earthquake.
The 7,200-foot Mount Mantap has been the site of all six nuclear tests conducted since 2006, and is now feared to be suffering from “tired mountain syndrome”.
Seismologist Paul G. Richards said: “What we are seeing from North Korea looks like some kind of stress in the ground.
“In that part of the world, there were stresses in the ground, but the explosions have shaken them up.”
Following the most recent and powerful test on September 3, when Pyongyang claimed it had set off a hydrogen bomb, the surrounding regionhas experienced three further quakes.
Before Kim Jong-Un‘s nuclear ambitions the area was not known to be affected by seismic activity.
Fears the mountain could collapse have been raised by Chinese scientists who fear radiation resulting from the tests would leak out into the atmosphere.
Satellite images show “numerous and widespread” disturbances resulting from detonations, according to DPRK experts 38 North.
The analysis reveals gravel and stones have been ejected from the ground before falling back to earth and settling.
Experts have also warned that Kim Jong-un’s next nuclear test is imminent after monitoring movement at the entrance tunnels to the test site.
A series of new tremors and landslides hit North Korea after an earthquake was recorded at the site last Friday.
Specialists suggest the quake, which measured 2.9 on the Richter scale, could mean the region has been destabilised by tests.
And they warned the Mount Mantap nuclear site may not be used to test nuclear weapons for much longer.
The United States Geological Survey (USGS) shows the quake was detected just 23 kilometres from Sungjibaegam, a town close to the Punggye-ri nuclear test site and added that it cannot confirm whether the earthquake was natural or man-made.
A statement from the US Geological Survey said: “This event occurred in the area of the previous North Korean Nuclear tests.
“The event has earthquake-like characteristics, however, we cannot conclusively confirm at this time the nature (natural or human-made) of the event.”