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 tomography better understand core, mantle, and plate tectonic processes. Tomography is solved as an inverse problem. Seismic travel time data are compared to an initial Earth model and the model is modified until the best possible fit between the model predictions and observed data is found. Seismic waves would travel in straight lines if Earth was of uniform composition, but the compositional layering, tectonic structure, and thermal variations reflect and refract seismic waves. The location and magnitude of these variations can be calculated by the inversion process, although solutions to tomographic inversions are non-unique. Seismic tomography is similar to medical x-ray