Why Did the US Conduct a Large Underground Explosion in Nevada?

October 1, Kathmandu – On Wednesday, the United States carried out a large underground explosion in Nevada. However, this explosion did not involve the use of a nuclear bomb. Scientists employed powerful chemical explosives to generate vibrations and other signals, which were recorded. The primary purpose of this experiment was to understand how to detect if any country attempts to conceal signs of a small underground nuclear detonation by masking its signals. This test was conducted amid ongoing US accusations that China has been carrying out covert nuclear tests. In 2020, China was alleged to have conducted such a secret test at the Lop Nur Nuclear Testing Center in Xinjiang.

During the Cold War, the US carried out hundreds of nuclear tests at the Nevada National Security Site, and the recent experiment was conducted at the same location. The test took place approximately 900 feet below ground level in the P-Tunnel area of the Nevada National Security Site, a tunnel used for national security purposes over many years. Scientists installed chemical explosives inside the tunnel and placed various sensors to record vibrations, sounds, and other post-explosion signals. Based on the data collected, computer models will be developed to enhance systems used to detect nuclear explosions. This effort will enable the United States to better identify potential nuclear detonations occurring anywhere worldwide.

Why Was a Nuclear Bomb Not Used? The US objective was not to conduct a nuclear explosion but to study the signals produced during underground explosions. Thus, scientists opted for chemical explosives instead of a nuclear bomb. Why Is It Difficult to Detect Covert Nuclear Explosions? Typically, an underground nuclear explosion generates strong vibrations similar to an earthquake. Sensors worldwide detect such tremors, and scientists analyze these signals to determine whether a nuclear test has occurred. However, the difficulty arises when the explosion’s signals are intentionally weakened—a process known in scientific terms as ‘decoupling.’ This involves detonating the explosion in locations such as large underground cavities, which dampen the impacts reaching the surface. This reduces the vibrations picked up by sensors, making detection challenging. The recent US experiment aims to detect such low-signal explosions.

China’s Denial of US Allegations In June 22, 2020, the US accused China of secretly conducting an underground nuclear test at the Lop Nur Nuclear Testing Center in Xinjiang. US officials reported recording a seismic shock of magnitude 2.75, which they claimed was not a natural earthquake or a mining blast. China dismissed US claims asserting the explosion was conducted in a large underground cavity using decoupling technology, thus explaining the weak signals. China denied carrying out any nuclear test and accused the US of making baseless allegations. Meanwhile, the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) stated that its monitoring network did not detect any clear signs of a nuclear test on that day. Although two minor seismic events were recorded, it was not possible to definitively conclude if they were caused by natural earthquakes, other blasts, or nuclear tests. (With agency contributions)