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 interferometry Seismic interferometry Interferometry examines the general interference phenomena between pairs of signals in order to gain useful information about the subsurface. Seismic interferometry (SI) utilizes the crosscorrelation of signal pairs to reconstruct the impulse response of a given media. Papers by Keiiti Aki (1957), Géza Kunetz, and Jon Claerbout (1968) helped develop the technique for "seismic" applications and provided the framework upon which modern theory is based. A signal at a location A can be crosscorrelated with a signal at a location B to reproduce a virtual source-receiver pair using seismic interferometry. Crosscorrelation is often considered the key mathematical operation