Martinez-Garzon, Patricia and Vavrycuk, Vaclav and Kwiatek, Grzegorz and Bohnhoff, Marco (2016) Sensitivity of stress inversion of focal mechanisms to pore pressure changes. Geophysical Research Letters, 43 (16). pp. 8441-8450. DOI: https://doi.org/10.1002/2016GL070145
Full text not available from this repository.Abstract
We investigate the sensitivity of stress inversion from focal mechanisms to pore pressure changes. Synthetic tests reveal that pore pressure variations can cause apparent changes in the retrieved stress ratio R relating the magnitude of the intermediate principal stress with respect to the maximum and minimum principal stresses. Pore pressure and retrieved R are negatively correlated when R is low (R < 0.6). The spurious variations in retrieved R are suppressed when R > 0.6. This observation is independent of faulting style, and it may be related to different performance of the fault plane selection criterion and variability in orientation of activated faults under different pore pressures. Our findings from synthetic data are supported by results obtained from induced seismicity at The Geysers geothermal field. Therefore, the retrieved stress ratio variations can be utilized for monitoring pore pressure changes at seismogenic depth in stress domains with overall low R.