<Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Underground nuclear testing is the test detonation of nuclear weapons that is performed underground . When the device being tested is buried at sufficient depth, the explosion may be contained, with no release of radioactive materials to the atmosphere . </P> <P> The extreme heat and pressure of an underground nuclear explosion causes changes in the surrounding rock . The rock closest to the location of the test is vaporised, forming a cavity . Farther away, there are zones of crushed, cracked, and irreversibly strained rock . Following the explosion, the rock above the cavity may collapse, forming a rubble chimney . If this chimney reaches the surface, a bowl - shaped subsidence crater may form . </P> <P> The first underground test took place in 1951; further tests provided information that eventually led to the signing of the Limited Test Ban Treaty in 1963, which banned all nuclear tests except for those performed underground . From then until the signing of the Comprehensive Test Ban Treaty in 1996, most nuclear tests were performed underground, in order to prevent nuclear fallout from entering into the atmosphere . </P>

Who developed the technology of underground nuclear explosion