North's mid-air detonation tests suggest will to kill

North Korea's recent tests involving the mid-air detonation of missile warheads are likely intended to maximize casualties in the event of hostilities with South Korea, according to Seoul’s intelligence and independent analysis by the JoongAng Ilbo.

In this photo released by Pyongyang's state-controlled Korean Central News Agency, the North Korean military launches a missile as part of an exercise aimed at rehearsing the ″devastation″ of South Korean command nodes and communications. [YONHAP]

North Korea’s recent tests involving the mid-air detonation of missile warheads are likely intended to maximize casualties in the event of armed hostilities with South Korea, according to Seoul’s intelligence and independent analysis conducted by the JoongAng Ilbo.

The altitudes at which the North’s missile warheads detonated during tests have been included in recent reports by Pyongyang’s state media, suggesting that the regime is sending a message that it could inflict serious loss of life or injuries on South Korean civilian populations.

For example, a 10-kiloton tactical nuclear warhead that detonates at a 400-meter (1,312-feet) altitude over central Seoul — the same as a test warhead on a KN-24 short-range ballistic missile launched into the East Sea late last month — would likely kill 46,510 South Koreans and seriously maim 164,850 more, according to the JoongAng Ilbo’s analysis.

The JoongAng Ilbo reached that estimate using Nukemap, an online map tool developed by Alex Wellerstein, a historian of science at the Stevens Institute of Technology, that calculates the effects of the detonation of a nuclear bomb.

Such a warhead would also generate a fireball approximately 153 meters in radius and destroy all residential buildings within 1.36 kilometers (0.84 miles) of the detonation point, while the resulting shockwaves would likely hit a total area of 41.7 square kilometers (10,304 acres).

In another test publicized on Saturday, the North’s state media said that test warheads mounted on what appeared to be recently developed Hwasal-1 or Hwasal-2 cruise missiles detonated at a pre-set altitude of 150 meters.

If such cruise missiles successfully evaded South Korean air defenses and detonated over Seoul City Hall at an equivalent distance above ground, approximately 60,910 people would be killed and another 113,870 would be seriously injured.

At a parliamentary intelligence committee briefing on Monday, officials from South Korea’s National Intelligence Service (NIS) told lawmakers that the North’s reports on mid-air missile warhead detonation are aimed at “testing the power of tactical nuclear weapons” and indicate the North’s military tactics in the event it decides to recommence full-scale hostilities against the South.

Beginning this year, the North has frequently included the altitude at which its various missile warheads exploded in its media reports, highlighting the regime’s ability to control their detonation.

On March 19, the Pyongyang’s state media reported that it had “verified” devices that control and ignite tactical nuclear warheads during a test launch of a KN-23 short-range ballistic missile that detonated at a pre-set altitude of 800 meters.

Three days later, the regime also said that it had tested igniting a warhead on a “strategic cruise missile” at 600 meters above ground, followed shortly after by a test of a KN-24 missile on March 27 at an altitude of 500 meters.

In this photo released by the Pyongyang's state-controlled Korean Central Televsion on March 28, a warhead on a North Korean KN-24 short-range ballistic missile launched the day before detonates mid-air. In its report, the KCTV claimed that the missile warhead detonated mid-air at an altitude of 500 meters. [YONHAP]

According to Kwon Yong-su, a missile expert and former professor at the Korea National Defense University, the North’s recent tests of warhead detonation at varying altitudes suggest that the regime is focusing on drawing up tailored plans to attack South Korean civil and defense facilities in the event of war.

“The optimal altitude [of detonation] can vary depending on the intended strike target sites and personnel,” he said, adding that this would explain why the North “appears to be carrying out different tests.”

According to Nukemap, the optimal altitude for a 10-kiloton tactical nuclear weapon to maximize casualties is a detonation point just over 1 kilometer from the ground, but such a weapon would have to explode at an altitude of just 102 meters to destroy a reinforced concrete structure.

A South Korean military official who spoke on condition of anonymity told the JoongAng Ilbo said that the North’s announcement that it had conducted a missile launch exercise to rehearse “devastating” command nodes and communications in the South was “likely intended to emphasize its capabilities.”

BY LEE KEUN-PYUNG,MICHAEL LEE [lee.junhyuk@joongang.co.kr]