Non-double-couple mechanisms of microearthquakes induced by hydraulic fracturing

Journal of Geophysical Research B: Solid Earth
By: , and 

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Abstract

We have inverted polarity and amplitude information of representative microearthquakes to investigate source mechanisms of seismicity induced by hydraulic fracturing in the Carthage Cotton Valley, east Texas, gas field. With vertical arrays of four and eight three-component geophones in two monitoring wells, respectively, we were able to reliably determine source mechanisms of the strongest events with the best signal-to-noise ratio. Our analysis indicates predominantly non-double-couple source mechanisms with positive volumetric component consistent with opening cracks oriented close to expected hydraulic fracture orientation. Our observations suggest the induced events are directly the result of opening cracks by fluid injection, in contrast to many previous studies where the seismicity is interpreted to be primarily shearing caused by pore pressure diffusion into the surrounding rock or associated with shear stresses created at the hydraulic fracture tip.

Publication type Article
Publication Subtype Journal Article
Title Non-double-couple mechanisms of microearthquakes induced by hydraulic fracturing
Series title Journal of Geophysical Research B: Solid Earth
DOI 10.1029/2008JB005987
Volume 114
Issue B8
Year Published 2009
Language English
Publisher American Geophysical Union
Contributing office(s) Volcano Hazards Program
Description Article B08307; 15 p.
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