New Insights on Alleged Chinese Nuclear Test

A high-ranking US official shared fresh information regarding China’s purported underground nuclear test from June 2020.

During a gathering at the Hudson Institute in Washington, Assistant Secretary of State Christopher Yeo disclosed that Kazakhstan’s seismic observatory had detected a magnitude 2.75 “explosion” on June 22, 2020, approximately 450 miles from the Lopnor test site in western China.

“We’ve analyzed more data since then, and it seems unlikely this was anything but an explosion—a singular explosion,” Yeo explained, noting that the findings did not align with a typical mine explosion.

“This doesn’t resemble an earthquake at all,” he added. Yeo, who comes from a background in intelligence and has a PhD in nuclear engineering, stated, “That’s what one would expect from a nuclear test.”

However, the Comprehensive Nuclear-Test Ban Treaty Organization mentioned there isn’t enough evidence to firmly back Yeo’s assertions.

A representative from the Chinese embassy in Washington dismissed the claims, labeling them as “totally baseless” and suggested they served as a pretext for the US to reignite its own nuclear testing.

“This is just a political tactic aimed at maintaining nuclear dominance and shirking responsibility for nuclear disarmament,” said Chinese Embassy Spokesperson Liu Pengyu in a statement.

Liu further urged the United States to reaffirm its commitment—along with the other nuclear-armed states—to abstain from nuclear tests and to uphold international agreements regarding nuclear disarmament and non-proliferation.

China Disputes Nuclear Test Allegations

China, which signed but has not ratified the 1996 treaty banning nuclear tests, rejected the allegations made by the US at an international conference earlier this month. Notably, China’s last verified underground test occurred in 1996.

The PS23 seismic observatory in Kazakhstan is part of a global monitoring network affiliated with the CTBTO. Robert Floyd, the organization’s executive director, reported that on June 22, 2020, two minor seismic events were recorded just 12 seconds apart.

CTBTO’s system is equipped to identify events resembling a nuclear explosion exceeding 551 tons of TNT. “These two events were significantly below that threshold,” Floyd stated, indicating that determining their cause based solely on the available data is challenging.

Yeo mentioned that China appeared to be using a technique called decoupling to mask the test, which involves detonating a device within a large underground chamber to lessen the shock wave transmitted through surrounding rock.

Interestingly, while the U.S. has also signed the nuclear testing ban, it has yet to ratify it. By international law, both countries are expected to adhere to the agreement.

The last underground nuclear test conducted by the United States was in 1992, after which it has depended on a costly program using advanced tools and supercomputer simulations to maintain its nuclear arsenal’s effectiveness.

In response to President Trump’s calls for a trilateral agreement involving the US, Russia, and China, China has remained firm, arguing that its nuclear capabilities are substantially less than those of the U.S. and Russia.

The Pentagon reports that China currently possesses over 600 operational nuclear warheads, and it’s expanding its nuclear forces rapidly. Estimates suggest that China may have more than 1,000 warheads ready by 2030.