Just hours after announcing they had developed a more advanced nuclear weapon — claimed to be a hydrogen bomb — North Korea conducted its sixth nuclear test. The test was the nation’s most powerful to date, with the U.S. Geological Survey measuring tremors at a magnitude of 6.3, while South Korea measured it at the much lower magnitude of 5.7. According to the New York Times, both measurements would indicate a weapons test “five to six times” more powerful than the nation’s previous nuclear tests. Estimates place the power of the blast at 120 kilotons and the DPRK referred to it as a “complete success.”
South Korea, China, and Japan condemned the test soon after, with South Korea saying the test is an “absurd strategic mistake” and the Japanese calling a sixth test “extremely unforgivable” while filing a protest with North Korea’s embassy in Beijing. They have also requested an emergency meeting of the United Nations Security Council over the incident.
Experts confirmed that the device seen in images shared by North Korea hours before the test did resemble a “two-stage thermonuclear device,” but doubts were cast. David Albright, president of the Institute for Science and International Security, told the New York Times that he questioned both at the device being authentic and the claim that the nation could mount any device onto an Intercontinental Ballistic Missile:
“The size of the seismic signal of the recent test suggests a significantly higher explosive yield than the fifth test,” Mr. Albright said. “Getting this high of a yield would likely require thermonuclear material in the device.”
But he said he was “skeptical that this design has been miniaturized to fit reliably on a ballistic missile.”