North Korea confirms third underground nuclear test

Added by on February 12, 2013

Seismograph comparing North Korea's 2009 nuclear test (shown in blue) to the nuclear test conducted on February 12 2013. Researchers say the seismograph of a nuclear test is very different from that of an earthquake.

Seismograph comparing North Korea’s 2009 nuclear test (shown in blue) to the nuclear test conducted on February 12 2013. Researchers say the seismograph of a nuclear test is very different from that of an earthquake.

The KCNA, North Korean Central News agency – North Korea’s state news agency – reported confirmation of a nuclear test by the country on Tuesday.

The televised official news report said North Korea’s test was partially in response to the United States which, North Korea says, violated their “republic’s right for peaceful satellite launch,” in reference to North Korea’s launch of a satellite on April 13 2012.

The test, conducted underground, was detected by seismic sensors around the world. The USGS, United States Geological Survey, detected a magnitude 4.7 earthquake in a region that is not naturally susceptible to earthquakes. The USGS’ report indicated the seismograph readings were identical to those of North Korea’s nuclear tests on October 9 2006 and May 25, 2009 – both of which were confirmed to be nuclear tests.

“The seismograph of a nuclear test is very different from that of an earthquake. The type of forces generated by man-made events radiate out wards from the location of the event in an up and down manner as opposed to the horizontal forces that occur in earthquakes,” said a researcher.

The nuclear device that was detonated in the same region as the previous tests had an estimated yield of six to seven kilotons – the nuclear bomb the United States dropped on Hiroshima in 1945 had a yield of 15 kilotons.

The KCNA said the nuclear device was smaller and lighter than the ones used in 2006 and 2009 and had “greater explosive force”. North Korea’s 2006 nuclear test had a reported yield of one kiloton.

Although unconfirmed, scientists say the nuclear device could have used uranium, raising concerns that North Korea may have the capability to produce a larger number of nuclear devices as compared to their capability in the past. Previous tests were conducted using plutonium derived from North Korea’s limited supply, which is extracted from the country’s non-operational nuclear reactors. It was estimated North Korea ha enough plutonium for six nuclear devices, yet uranium, which the country has been working on for years to refine increases their capability to produce nuclear weapons in large numbers.

It is thought that North Korea may have collaborated with Iran, which has also been working on it’s uranium refining capabilities.

Japan and the United States have reportedly dispatched aircraft with specialized sensors to determine whether the test resulted in the release of radioactivity into the atmosphere and if it did, to determine whether the nuclear device used plutonium or uranium. North Korea’s 2006 nuclear test leaked radioactive particles into the atmosphere which were detected as far away as Yellowknife, Canada which is about 4,500 miles (7,242km) from the test site.

Underground nuclear tests are considered to a smaller risk of leaking radioactive particles into the atmosphere as compared to tests conducted above ground, or underwater.

A nuclear test on December 18 1970 by the United States released radioactive particles 10,000ft (approximately 3km) into the atmosphere above the test site. The radioactive particles spread westward into neighboring states. An official report stated the release was accidental and the result of unexpected geological features surrounding the test site.

North Korea’s nuclear underground test capabilities are said to have advanced very quickly. Scientists say the country is able to manage the complexity of constructing an underground test facility, although they caution the degree of complexity is very high. The United States had conducted well over 1,000 nuclear tests when the 1970 event occurred.

The United States and many other countries condemned the test, and the UN security council was reportedly preparing for an emergency meeting.

The United States conducted over 2,000 tests with over 75% tested underground; the total number of nuclear tests by the United States exceeded the combined total number of tests conducted by other countries around the world.

Nuclear testing helps scientists collect data that contributes to the development of not only nuclear capability, but also the capability to make the nuclear device small enough to be carried by a missile.

Underground nuclear testing is usually carried out in specially constructed vertical tunnels located approximately 250m below ground. Test facilities are usually constructed in regions with a stable geology, sometimes located in mountains areas because they are remote and are often composed of hard granite rock.