A systematic analysis of seismic moment tensors of earthquakes in the subduction zones of the Aleutian, Kuril-Kamchatka and Japanese island arcs was carried out. A method for identifying earthquakes with foci that do not satisfy the double dipole model (NDC-type earthquakes) is applied, based on estimating the angle between the slip vector and the rupture plane in the earthquake focus using data on the seismic moment tensor main values. A study of the error distribution in the estimates of the moment tensor components made it possible to identify earthquakes with a significant NDC component of the focus. Some distribution features of such earthquakes in the studied region are discussed. Comparison of the results of identifying foci with a significant NDC component according to data from various seismological agencies showed that the absolute values of the angle between the slip vector and the rupture plane were somewhat underestimated in the catalogs of the US Geological Survey (NEIC) and the Japanese Institute of Earth Sciences (NIED) compared to the Global Centroid Moment Catalog (GCMT). The applied method and the obtained estimates of the NDC component of slip in earthquake foci can be used in numerical modeling of movements in the foci of strong earthquakes using a set of ground-based and satellite deformometric data.
E.A. Marshakova (Wed,) studied this question.