Non-local deformation effects in shear flows

Abstract. The method for detection of clusters on the basis of event space–time dependence is classically applied for foreshock–mainshock–aftershock sequences for which event connectedness is generally accepted. In the paper, this approach is used to investigate the whole event catalogue of foreshock and aftershock sequences filtered from the events with small magnitudes, in which connected events are also determined. The space scale is extended due to the inclusion of the parameter of seismic event connectedness in the direction of dislocation shift that allows us to consider the obtained connected events as clusters in a shear flow. A statistical model of the shear flow was constructed by catalogue decomposition into timescales and space scales defined analytically. A modelling algorithm of the shear flow was developed and its stability to initial condition change was investigated. Shear flow structure and arising non-local deformation characteristics which may be the criteria for dynamic process activity in the considered subduction zone of the Kuril–Kamchatka island arc were analysed.