Damage Tensor Analysis on Regional Seismic Status

INTRODUCTIONThe introductiontothe damage variable was made originally by Kachanov (1958) and Rabotnov(1963) .As a factor of deterioration in material or rock,damage develops with the changing of loadand environment . The damage variable describes the characteristics of material in the stage frommicrofissure generationto macrofracture formation.Grady and Kipp (1980) loaded oil shale at a constant strainrate andits damage degreeincreasedrapidly. Whenthe load reachedits utmost ,collapse occ…

Damage Tensor Analysis on Regional Seismic Status

In this paper, we researched the regional seismic status by using theories of the Damage Mechanics. The macroscopic damage status of the earth crust block, which is caused by earthquake fracture, is described with several concepts-the damage degree, the damage rate and the strain rate. In the earthquake process, the average strain rate of the studied block is equal to the sum of all seismic moment tensors of the earthquakes taking place in unit time and physical volume. To describe the anisotropy of microdamage of the crust block, we use the damage tensor that is expressed in the fissure density. By means of the transformation from the focal coordinate system to the observation system, we obtained the external normal vector of the focal fault plane expressed in its observation system and obtained the macrodamage degree of the researched block, which is calculated in dyadic. This provides a new analysis method for recognizing the underground damage status and the stress status.