Kaiser effect (material science) Kaiser effect (material science) The Kaiser effect is a phenomenon observed in geology and material science that describes a pattern of acoustic emission or seismicity in a body of rock or other material subjected to repeated cycles of mechanical stress. In material that exhibits an initial seismic response under a certain load, the Kaiser effect describes the absence of acoustic emission or seismic events until that load is exceeded. The Kaiser effect results from discontinuities (fractures) created in material during previous steps that do not move, expand, or propagate until the former stress is exceeded. Induced seismicity associated with fluid
Seismic anisotropy Seismic anisotropy Seismic anisotropy is a term used in seismology to describe the directional dependence of the velocity of seismic waves in a medium (rock) within the Earth. A material is said to be anisotropic if the value of one or more of its properties varies with direction. Anisotropy differs from the property called heterogeneity in that anisotropy is the variation in values with direction at a point while heterogeneity is the variation in values between two or more points. Seismic Anisotropy can be defined as the dependence of seismic velocity on direction or upon angle. General anisotropy is described