The Best in Science News and Amazing Breakthroughs
Since the first detonation of an atomic bomb in 1945, more than 2,000 nuclear weapons tests have been conducted by eight countries: the United States, the Soviet Union, the United Kingdom, France, China, India, Pakistan and North Korea.
In 1963, the US, the UK and the USSR agreed to carry out future tests underground to limit fallout. Nevertheless, testing continued unabated as China, India, Pakistan and North Korea also entered the fray over the following decades.During this period there were substantial international efforts to figure out how to monitor nuclear testing. The competitive nature of weapons development means much research and testing is conducted in secret.
The difficulty in using seismic waves to monitor underground nuclear tests is distinguishing between explosions and naturally occurring earthquakes. A core goal of monitoring is never to miss an explosion, but there are thousands of sizeable natural quakes around the world every day. However, these simple methods are not foolproof. Tests might be carried out in earthquake-prone areas for camouflage, for example, and shallow earthquakes are also possible.
This outcome underlines the importance of using multiple independent discrimination techniques during monitoring – no single method is likely to prove reliable for all events.In 2023, my colleagues and I from the Australian National University and Los Alamos National Laboratory in the US got together to re-examine the problem of determining the source of seismic waves.