Effects of rock damage on seismic source characteristics of underground nuclear explosions

In this paper we readdress the effects of rock damage on seismic radiation and its source representation taking account of the existence of dynamic force disturbances in the source. We proved that, when dynamic force distur-bances exist, the result given by Ben-Zion and Ampuero in 2009 is not for the whole seismic wave field but for the contribution by the nonelasticity. Furthermore, based on the theoretical formulations obtained in this paper, we analyzed effects of rock damage upon source characterizations of underground nuclear explosions and relationships between rock damages and their non-isotropic secondary sources including the compensated linear vector dipole (CLVD) and tectonic stress release. The results show that, the CLVD of an underground explosion mainly comes from rock damages within a cone area above the explosion itself which is induced by surface reflected tensional shock waves and cavity rebound, while the tectonic stress release may be caused by stress relaxation within whole damaged area of the explosion.