2D Finite Element Modelling of Regional and Local Fracture Networks in the Eastern California Shear Zone and Coso Range, California USA

摘要

Geothermal energy production from the Coso field, located in the Eastern Californian Shear Zone, is reliant on a thorough understanding of the fluid flow network, which is controlled by the distribution and interaction of fractures and permeability. This paper presents the results of 2D linear elastic finite element (FE) modelling investigating the influence boundary conditions on the deformation field across the Coso Range, California. Loads equivalent to the motion of the main tectonic elements and internal fault slips yield results that compare favourably to published strain orientations and natural seismicity. Comparison of predicted shear fractures, generated using fracture potential, to seismicity shows that fracture reactivation, rather intact rock failure, is the most active brittle process. The numerical results support the concept that transtension in the Eastern California Shear Zone is driven by the relative NW motion of the Sierra Nevada Block.