The "unusual seismic event" was also detected by several earthquake monitoring stations around the world.
According to the government-funded Korea Institute of Geoscience and Mineral Resources, the U.S. Geological Survey as well as earthquake monitoring stations in South Korea have detected a 4.9 magnitude earthquake near the site where North Korea conducted its second nuclear test in 2009. USGS says the earthquake was recorded at a depth of about 1 kilometer.
reports that Chi Heoncheol, an earthquake specialist at the institute, said: "There is a high possibility that North Korea has conducted a nuclear test."
South Korean, U.S. and Japanese seismic monitoring agencies estimate the magnitude of the earthquake between 4.9 and 5.2. A Japanese government spokesman Yoshihide Suga, said at a news conference Tuesday: "We think it is possible it came about as a result of a nuclear test by North Korea from looking at past cases."
The Los Angeles Times
reports that South Korea's Yonhap
news agency said the tremor occurred deep in the mountains of North Hamgyong province, near the village of Punggye-ri about 80 miles from the Chinese border.
According to MSN News
, Tibor Toth, executve secretary of the Comprehensive Nuclear Test Ban Treaty Organization, said: "The event shows clear explosion-like characteristics and its location is roughly congruent with the 2006 and 2009 DPRK nuclear tests... If confirmed as a nuclear test, this act would constitute a clear threat to international peace and security, and challenges efforts made to strengthen global nuclear disarmament and non-proliferation, in particular by ending nuclear testing."
South Korea's Yonhap
news agency reports that after North Korea threatened a third nuclear test it informed Beijing and Washington Monday of its intention to go ahead with the test.
North Korean officials have not made any comments following news that the country may have conducted a third nuclear test, Reuters
reports. If the seismic activity detected is confirmed to be a nuclear test, North Korea would have acted in defiance of UN Security Council resolutions that ban the country from developing nuclear and missile technology.
Certainty that the 4.9 magnitude seismic activity detected was a nuclear test is based on the fact that North Korea is not prone to seismic activity. CNN
reports that according to U.S. Geological Survey maps, the area around the reported epicenter of the tremor has no history of natural seismic activity.
Experts say natural tremors may be distinguished readily from artificial tremors set off by nuclear detonations. Yosuke Igarashi, an official at the Japan Meteorological Agency, said: "A natural earthquake normally starts with a smaller tremor followed by a larger one. This quake's strength was the same throughout."
A magnitude 3.9 earthquake and a magnitude 4.5 earthquake with similar characteristics were detected when North Korea carried out nuclear tests in 2006 and 2009.
South Korea's defense ministry said the seismic event could have been triggered by a 6-7 kiloton weapon or even stronger.
North Korea violated UN resolutions banning it from developing and testing missiles and nuclear weapons when it successfully launched a long-range rocket in December. After the successful rocket test, the country announced plans for a third nuclear test claiming it was in protest of sanctions imposed in January after the rocket launch.
Analysts say any test by North Korea will be aimed at developing a warhead that can be mounted on a missile. The prospects of the North Koreans developing miniaturized weapons are worrisome to the US and countries in the region. China, North Korea's main ally in the region, has expressed the common concerns of the region's major powers when it threatened to cut back on food assistance to North Korea if it proceeds with the planned test. China donates about half of the balance of food the country needs and about half of the oil the country consumes.
The Los Angeles Times
reports that Global Times
, a newspaper affiliated to the Chinese Communist Party, said in a recent editorial: "If North Korea engages in further nuclear tests, China will not hesitate to reduce its assistance to North Korea."
comments that with the news of the tremor believed to be a nuclear test coming hours before President Obama delivered the State of the Union address, new secretary of State John Kerry may have received his first major diplomatic assignment in the region.
North Korea's National Defense Commission had said that the US is the prime target of its missiles and weapons program. A spokesman for the commission claimed last October that North Korea has built a missile capable of hitting targets in the US. Foreign experts have not confirmed the claim but a missile that appeared to be an ICBM featured in an April 2012 military parade. Many experts say it could be fake.