Tip-slip source mechanisms and hydraulic fracture microseismicity

摘要

Observations of fault plane solutions for microseismic events are often presented as apparent dip-slip solutions on vertical discontinuities. We propose an alternative explanation for these observations: the mechanism is not "dip-slip" on vertical structures but hydraulic fracture "tip-slip" on the auxiliary plane i.e. horizontal slip on horizontal structures. The reason for the ambiguity is because both the dip-slip and tip-slip mechanism produce the same seismic radiation pattern in the far field.