- Anak Krakatau - the child of Krakatoa.
The first observation of naturally occurring infrasound that was ever recorded using instruments was in the aftermath of the 1883 eruption of the Krakatoa volcano in Indonesia. Infrasonic waves that circled the globe at least seven times shattered windows hundreds of miles away, and were recorded worldwide.Infrasonic waves cause minute changes in the atmospheric pressure which are measured by microbarometers. Infrasound has the ability to cover long distances with little dissipation, which is why infrasound monitoring is a useful technique for detecting atmospheric nuclear explosions.
The adoption of the CTBT had a revitalizing effect on infrasound research. The ban on atmospheric nuclear tests brought about by the Partial Test Ban Treaty (PTBT) in 1963 somewhat diminished the interest in infrasound science and technology. The construction of infrasound monitoring stations as part of the CTBTO’s global alarm system to monitor the earth for nuclear explosions has contributed to a revival of scientific interest in this technology.
- The explosion at a London oil depot in December 2005 was recorded at infrasound station IS26 in Freyung, Germany.
Infrasound technology has considerable potential for civil and scientific applications, not least in disaster prevention or mitigation.
For information on what scientific and civil applications infrasound can be used for, please click here.
Objectives
Infrasound monitoring is one of the four technologies used by the International Monitoring System (IMS) to verify compliance with the CTBT. Atmospheric and shallow underground nuclear explosions can generate infrasound waves that may be detected by the infrasound network.
- Arrays of infrasound station IS49, Tristan da Cunha, United Kingdom.
By focusing mainly on the detection of a suspected nuclear explosion in the atmosphere, infrasound technology helps to identify the location of the explosion. The ability to provide such information enhances the potential for a successful on-site inspection in case of atmospheric nuclear explosions.
In addition, since underground nuclear explosions also generate infrasound waves, the synergetic use of both the infrasound and the seismic technologies allows for better information gathering and analysis of possible underground tests.
