US Releases New Details on Alleged 2020 Chinese Nuclear Test

The blast is not consistent with an earthquake, said one expert: ‘It is ... what you would expect with a nuclear explosive test.’

People's Liberation Army soldiers march past an old Chinese medium range ballistic missile on display in front of Beijing's military museum on July 26, 1999. Stephen Shaver/AFP via Getty Images

A senior State Department official released additional evidence on Feb. 17 in support of U.S. allegations that China conducted an underground nuclear test in June 2020, as global arms control frameworks unravel.

Assistant Secretary of State Christopher Yeaw, while speaking to a Hudson Institute meeting, discussed data from a remote seismic station in Kazakhstan that recorded a magnitude 2.75 “explosion” approximately 450 miles from China’s Lop Nur test grounds on June 22, 2020.

“I’ve looked at additional data since then. There is very little possibility I would say that it is anything but an explosion, a singular explosion,” said Yeaw, a former intelligence analyst and defense official who holds a doctorate in nuclear engineering.

“It’s also entirely not consistent with an earthquake. It is ... what you would expect with a nuclear explosive test.”

Yeaw claimed that China tried to hide the event through decoupling, detonating the device in a spacious underground cavity to diminish seismic waves.

Under Secretary of State for Arms Control Thomas DiNanno earlier this month accused China of performing such secretive nuclear arms tests and implementing measures to restrict seismic evidence.

“Today, I can reveal that the U.S. Government is aware that China has conducted nuclear explosive tests, including preparing for tests with designated yields in the hundreds of tons,” DiNanno said.

These claims back up Yeaw’s assertions of concealment tactics.

The Comprehensive Nuclear-Test-Ban Treaty Organization, which monitors global explosions, noted that available data do not allow for firm conclusions. Executive Secretary Robert Floyd said in a statement that the seismic monitoring station in Kazakhstan captured “two very small seismic events” 12 seconds apart on June 22, 2020.

The organization’s network detects events equivalent to 551 tons of TNT or more, according to Floyd.

“These two events were far below that level,” Floyd said. “As a result, with this data alone, it is not possible to assess the cause of these events with confidence.”

China, a signatory to the 1996 Comprehensive Nuclear-Test-Ban Treaty but not a ratifier, rejected the initial U.S. accusation at an international conference this month. Beijing’s last acknowledged underground test occurred in 1996.

The United States, which also signed but did not ratify the treaty, is legally bound to its terms under international norms. The United States’ final underground test was in 1992, and it has since relied on sophisticated simulations and supercomputers for warhead maintenance.

U.S. President Donald Trump recently called on China to take part in trilateral talks with Russia to support the New Strategic Arms Reduction Treaty (New START), which ended on Feb. 5.

China refused the invitation, arguing that its arsenal is far smaller than those of the United States and Russia. The Pentagon estimates that China currently has more than 600 operational warheads. The stockpile is expected to exceed 1,000 by 2030.

According to tracking by the Federation of American Scientists, an organization working to minimize the risks of nuclear threats, Russia currently has 5,459 warheads, and the United States has 5,177.

The New START expiration removes caps on deployed strategic warheads and delivery vehicles, potentially accelerating buildups. Russia and the United States said they would informally observe limits.