Contemporary stress field in and around a gold mine area adjacent to the Bohai Sea, China, and its seismological implications.

The contemporary stress field in and around a gold mine area (GMA) and its seismological implications were investigated based on overcoring stress measurements and focal mechanism solutions. The results indicate that the stress level of the GMA appears to be relatively high, and stress states are characterized by reverse and strike-slip faulting stress regimes, which vary somewhat with depth. The stress field is governed by the maximum horizontal stress, which is well oriented along the WNW–ESE or approximately E-W directions, revealing a uniform stress direction. This dominant stress orientation is identical to the regional tectonic stress field interpreted by various independent geological indicators, and the stress field is mainly caused by the combined actions of far-field, near-field, and local forces. The stress conditions suggest that this region is in the subcritical equilibrium state, so frictional sliding probably occurs along the pre-existing and cohesionless faults that are optimally oriented to the stress field. Moreover, the ratio of the maximum shear stress to the effective mean principal stress (μm) values of 0.3 to 0.5 can be used as the lower and upper critical bounds for future geodynamic-related prediction analysis in and around the GMA and other possible regions. [ABSTRACT FROM AUTHOR]