hankyoreh

after the North nuclear test was announced. Pyongyang

North Korea announced on the morning of October 9 that it had conducted its first nuclear weapons test. The question now - aside from confirming that a test did indeed take place - is determining exactly how strong a force was the explosion.

Experts worldwide say the strength of the seismic waves detected on the day are not enough evidence to conclude whether the North's alleged nuclear test was a success or not, or even occurred. Other information, such as detection of a radioactive isotope in the atmosphere, should be completed to make a final judgment, these experts say.

Given the size of the tremors that have so far been detected - 3.58~3.7 on the Richter scale - the North's nuclear test is estimated to be equivalent to more than 800 tons of TNT according to the Korea Institute of Geoscience and Mineral Resources.

The institute had originally calculated the size of the explosion to be between 400 and 800 tons of TNT, but has raised it to the current figure.

The institute said it could not calculate the exact maximum size of the nuclear explosion, but added the maximum size will not pass five kilotons. France's Atomic Energy Commission has put the blast as equivalent to 1 kiloton of TNT, while Russia's defense minister said there was "no doubt" that North Korea had held a nuclear test and said the force of the underground blast was equivalent to 5,000 to 15,000 tons. China was believed to have told South Korea that the test may have been equivalent to 10 kilotons of TNT about 10 to 20 minutes before the actual test.

The estimate of 800 tons of TNT would represent a relatively small-scale nuclear weapons test, experts say. The two atomic bombs that hit Hiroshima and Nagasaki in 1945 had the power of 15 and 22 kilotons each.

However, the size of the explosion is meaningless as far as a country becoming a "nuclear state," experts say. India and Pakistan, which tested nuclear devices in 1998, performed a wide range of tests with nuclear warheads sized from tens of kilotons to 1 kiloton.

Lee Sang-ho, a Kyonggi University professor and a former National Security Council member, said, "In a nuclear test, the size of the explosion is meaningless; this could vary with the type of warhead."