North Korean nuclear test also recorded in Switzerland

The seismic waves generated by the North Korean nuclear test on February 12, 2013 (02:57 UTC, 03:57 Swiss local time) reached the seismic monitoring stations in Switzerland approximately 12 minutes later. That this event was an explosion rather than an earthquake can be deduced from the seismic waveforms. For an explosion the amplitude of the first arriving P-wave is relatively stronger than the later arriving S-Wave, compared to an earthquake.

The power of the explosion corresponds to an earthquake magnitude of 5, thus this test was significantly stronger than the two previous ones in 2006 (magnitude 4.1) and 2009 (magnitude 4.5). The location of the event in the North Korean province Northern Hamgyong as determined by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) and confirmed by other global seismological agencies, suggests that the test of February 12, 2013 took place at the same location as the previous ones.

The SED station DAVOX near Davos (GR) is the Swiss contribution to the currently 146 seismic stations of the CTBTO's International Monitoring System.

Further information on the nuclear test from CTBTO

Event summary from the USGS

General information about verfication of nuclear test explosions from the SED