Background
The North Korean nuclear test on 9 October 2006 was the first (and until now the only) nuclear explosion that has taken place after the CTBT organization in Vienna, Austria began, in February 2000, regular processing of signals from a global monitoring network. This network, which is now nearing completion, uses seismic, radionuclide, infrasound and hydroacoustic technologies, and will, when completed, comprise more than 300 monitoring stations. Six of these stations, among them some of the largest and most advance ones, are situated on Norwegian territory and are operated by NORSAR.
The North Korean nuclear explosion was detected and located immediately after it took place, and the global monitoring system thus passed this unforeseen test. From radionuclide measurements, it became clear that the explosion was nuclear (and not chemical). The size of the explosion was relatively moderate, with a Richter magnitude of 4.2. This corresponds to approximately one kiloton of TNT if the explosion was fully coupled and carried out in hard rock.
Data analysis at NORSAR
Even if NORSAR is not conducting regular monitoring, the NORSAR array systems were able to detect the nuclear explosion automatically, and the explosion was reported to the authorities. The event clearly demonstrated the importance of having a global detection system. Based on analyzing the available recordings, NORSAR scientists have calculated the projected monitoring capability of the international seismic system for the North Korean test site (see Capability Assessment).
Recordings from one of NORSAR’s seismic monitoring stations (the ARCES array
near Karasjok, northern Norway). ARCES is located at a distance of 6260 km
from the explosion site, and the seismic pressure waves were recorded at this
station 9 minutes and 43 seconds after the explosion took place.
 The location of the North Korean explosion. |
