Observatories and Research Facilities for EUropean Seismology
Volume 2, no 2 August 2000 Orfeus Newsletter

Signals from the accident of the Russian submarine Kursk

NORSAR staff
NORwegian Seismic ARray, P.O. Box 51, N-2027 Kjeller, Norway.

On August 12, 2000 signals from one presumed underwater explosion in the Barents Sea were recorded on seismic stations in several countries. Among these were all the seismic arrays operated in Norway by the NORSAR seismological observatory. The estimated location of this event coincides well with the position where the accident of the Russian submarine Kursk took place.

Using detection data from several arrays in northern Europe, the main event was located fully automatically by the Generalized Beamforming process (GBF) at a distance of only 14 km from the known position of the submarine. The GBF process is running on-line at NORSAR for the purpose of providing trial epicenters of seismic events in Europe and the European Arctic.

Analyses of data from the ARCES array in northern Norway conducted by NORSAR indicate that there were two explosions. The larger explosion (Figure 3) observed at several stations occurred at 07.30.42 GMT at an estimated location of 69 degrees 38 minutes North, 37 degrees 19 minutes East. This explosion had a magnitude of about 3.5 on the Richter scale, corresponding to about 1-2 tons TNT detonated in water.

The smaller seismic event with a magnitude of about 1.5 was recorded from the same location 2 minutes 15 seconds earlier. This event was only observed at the small aperture ARCES array. The observed waveforms, onset times and backazimuths from ARCES suggest the same location as for the second larger event.

Figure 1. Seismic arrays operated by NORSAR in Norway.

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Figure 2. Estimated location of the event(s).

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Figure 3. NORSAR recordings of the main event in the Barents Sea on 12 August 2000

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Figure 4. Recordings of the two events in the Barents Sea on 12 August 2000 made in Finnmark, northern Norway.

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