North Korea's mysterious nuclear test generates weak seismic activity

North Korea has conducted a nuclear test. Russian scientists are at a loss: the Sakhalin seismic station did not record any tremors. South Korean sources say that there was seismic activity registered in the region of the North Korean test site, although it was weak: the activity corresponded to an explosion of 6-7 kilotons. For comparison, the power of the first nuclear bomb that Americans dropped in 1945 on the Japanese city of Hiroshima was 18 kilotons.

However, Pyongyang said that the nuclear test has been conducted. Pyongyang officials had previously notified China and the United States through diplomatic channels of the impending explosion.

South Korean authorities have already informed the UN Security Council of the nuclear test that was conducted in North Korea. The U.S. Geological Survey (USGS) recorded tremors in North Korea near the nuclear test site on Tuesday morning.

"We were informed by the South Korean side of the nuclear test in DPRK," UN Security Council diplomats said.

According to the U.S. Geological Survey, a 4.9-magnitude earthquake occurred at a depth of one kilometer. The epicenter of the quake was located 41,299 degrees north latitude and 129,081 degrees eastern longitude, 378 kilometers northeast of Pyongyang, near the town of Kilchu.

The Chairman of the Chiefs of Staff of South Korea, General Cho Jung-hwan, stated that the South Korean army would definitely strike a preemptive blow on North Korea if the armed forces of the country attempted to use nuclear weapons.