Each has been used separately, but at present the best results occur when data is used in tandem, since the energy caused by an explosion will transfer over to different mediums.
[citation needed] The main system for detecting underground detonations continued to require large numbers of monitoring stations.
Due to the difficulty in creating technology and the number of stations needed the PTBT allowed underground testing.
[7] Other problems that hydroacoustics face are the difficulties caused by the structure of the sea floor, as well as islands that can block sound.
[9] Infrasound works by having multiple stations that use microbarometers to listen for infrasonic waves caused by explosions, volcanoes or other natural occurring events.
[14] Sending planes over or near an area can reveal if there was a recent nuclear detonation, though most air samples are taken at one of many radionuclide stations set throughout the world.
[1] The detection process involves taking air samples with a filter paper which collects the radioactive material which can then be counted and analyzed by a computer.
[15] Radioactive iodine is an example of this, as it exists in many chemical forms, combined with an array of many different gases that are not suitable for direct reading methods using absorption or collection of a fixed volume in containers.
Spread by air currents, this led to radiation that could be detected as far as Sweden and other countries hundreds of miles away from the plant within a few days;[17] the same occurred at the Fukushima Daiichi disaster.
[18] Satellites rely on sensors to monitor radiation from nuclear explosions that always produce gamma rays, x-rays, and neutrons.
[3] Nuclear explosions release a massive burst of x-rays that occur repeatedly with an interval of less than 1 microsecond that could be detected by the satellite.
A minor drawback to the satellite detection method is that there are some cosmic rays that emit neutrons and could give false signals to the sensor.
Using collected data from each source to calculate detonations, the IMS employs hydroacoustic, infrasound, and seismic wave detection systems, as well as air samplers for radionuclides.
All of this information is collected by the Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) which is stationed in Vienna, Austria.