TOKYO -- Japan has begun seriously considering how to withstand and counter an electromagnetic pulse, or EMP, blast that would disable electronics and infrastructure, following North Korea's boast of having the means to mount such an attack.
On Sept. 3, the day Pyongyang conducted its sixth nuclear test, the state-run Korean Central News Agency said the country had developed a nuclear warhead that could also deliver an EMP attack. The powerful waves from such a blast would instantly overload electrical circuits within a certain range. The pulse would likely not cause direct bodily harm but could bring chaos in such areas as power supply and public transportation networks.
An EMP attack could come in two forms, broadly speaking. A high-altitude nuclear explosion, such as that mentioned by Pyongyang, at 30km or above would scatter electromagnetic waves across an extremely wide area. A 1962 nuclear test by the U.S. military, about 400km above the northern Pacific Ocean, caused blackouts as far as 1,400km away in Hawaii.
The second method would be dropping a bomb designed to trigger an EMP blast from a plane, for instance, at a low altitude. Such an explosion would cover a smaller area but be easy to train on a specific target, according to the Ministry of Defense. The U.S. military and others are said to possess such technology, which may have been used in the Iraq War in 2003.
Whether North Korea has indeed made EMP weapons a practical reality is unclear. Tokyo appears skeptical, with Defense Minister Itsunori Onodera describing a "sense of suddenness" about the KCNA report. But some countries certainly could possess such weapons -- such as Russia, believed to have been developing the technology during the Soviet era, and China, hurrying to add to its arsenal. Tokyo "would like to consider" EMP countermeasures, Chief Cabinet Secretary Yoshihide Suga has said.
Self-Defense Forces defense equipment and communications systems are prepared for an EMP attack, according to a Japanese government source. Certain equipment and circuits have apparently been covered with metal shielding or other protection so that they can work even in emergencies. The Defense Ministry has requested 1.4 billion yen ($12.8 million) in the government's fiscal 2018 budget for such steps as the production of an EMP weapon prototype for preparation of defenses.
But protections for civilian infrastructure are seen as lacking. An attack targeting nuclear power infrastructure, for instance, or such public transportation as aircraft could cause immense damage. The government convened Cabinet Secretariat members Friday, as well as representatives from relevant ministries -- such as for defense, the economy and transport -- to start planning countermeasures.
Unlike a cyberattack, an EMP attack could render critical infrastructure and systems permanently unusable. In the event of a situation effectively amounting to an armed attack, "depending on the scale of the damage, an armed counterattack by the Self-Defense Forces" would not be ruled out, a Cabinet Secretariat official said.