Аннотация:At convergent plate boundaries, the accumulated elastic strain is released mostly in great shallow thrust earthquakes. Understanding which fraction of the elastic strain due to plate motion is released in earthquakes is important in assessing the seismogenic potential at convergent boundaries where most of great earthquakes occur. Conventionally, an estimate of the released fraction of the total elastic strain relies on the Kostrov summation of GCMT moment tensors. However, the GCMT moments of great earthquakes can be erroneous by a factor of 2 because of parameterization as a simple point source with triangular moment-rate function and because of trade-off between estimates of the moment and dip angle. Therefore, assessment of the current seismic potential caused by plate motion can be wrong. For the great 2006-2007 Kuril earthquakes, coseismic moments from inversion of GPS offsets are larger than GCMT moments by at least a factor of 1.5. We attribute this disagreement to the simplified source model used in GCMT inversion. From kinematic GPS solution, a contribution of slow coseismic slip (captured by GPS but not by seismometers) was insignificant. Earlier, a similar disagreement between geodetic and GCMT moments was demonstrated for the great 2004 Sumatra earthquake.