Focal mechanisms from microseismic events contain an abundance of information. Moment tensor inversion can lead to a richer understanding of the failure mechanisms and stresses at work at the event source. This information cannot be ascertained from event hypocenter locations alone. Often events recorded during hydraulic fracturing are associated with double-couple (DC) source mechanisms. Hydraulic injection has been associated with non-shear source mechanisms, hence constraining the source mechanism to a shear solution is not appropriate.-Data from passive surface monitoring in the Horn River Basin are used to explore moment tensor decompositions: We show that events relating to hydraulic fractures contain significant compensated linear vector dipole (CLVD) components of failure and exhibit b-values of approximately 2. This event population is in contrast to fault reactivation events, which are highly double-couple and have a b-value of approximately 1. This work is part of an ongoing study to integrate geophysical, geological and engineering information.
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