Shear-wave splitting: New geophysics and earthquake stress-forecasting

Abstract

Shear-wave splitting in the Earth reveals a fundamentally new understanding of fluid-rock deformation, where APE-modeling shows that modifications to shear-wave splitting directly monitor stress-induced modifications to microcrack geometry. Since if the changing conditions can be specified, the deformation can be calculated and predicted by APE; this is a substantial advance, a New Geophysics, on conventional subcritical solid-earth geophysics. Changes in microcrack geometry can be monitored, calculated, predicted, and in some circumstances potentially controlled. There is extreme sensitivity to initial conditions, and universality, so that effects are widely and uniformly distributed. The New Geophysics allows stress-accumulation and stress-relaxation (crack-coalescence) before earthquakes to be recognized and impending large earthquakes stress-forecast. There are many important implications and applications. In particular, any solid-earth application that cannot accommodate compliant stress-aligned fluid-saturated EDA-microcracks pervading most in situ rocks is in error and may lead to serious misunderstandings. New Geophysics leading to monitorability; calculability; predictability; potential controllability; universality; extreme sensitivity; and earthquake stress-forecasting, is likely to be the most fundamental advance in solid-earth geoscience for many decades.