On 12 August 2000 two explosions damaged the Russian submarine, the Kursk.
The largest event was well recorded at seismic networks in northern Europe,
which we then modeled. We developed a hybrid method based on generalized r
ay theory that treats an explosive source embedded in a fluid and recorded
along continental paths. Matching record sections of observations with synt
hetics, we obtain an estimate of explosive size of slightly over 4 t. Sever
al earth models determined previously, K8 and a Baltic model, were used to
assess accuracy. These results are in general agreement with other investig
ators using more empirical methods. Knowing the conventional missile yield
and the explosion size allows for an estimate of approximately five missile
s exploded in the second larger explosion onboard the Kursk.