Fluid Injection Triggers Large‐Scale Slow‐Slip Activation of the Rocky Mountain Fold and Thrust Belt

Abstract

Abstract Using interferometric synthetic aperture radar (InSAR) we show that hydraulic fracturing treatments near the subsurface deformation limit of the Rocky Mountain Fold and Thrust Belt produced 12 intraplate, aseismic, slow‐slip events with magnitudes 4.71–5.06 at 1,640–2,410 m depths. Sustained aseismic slip is inferred to occur on the bedding‐parallel roof detachment of a duplex, thrust‐fault system. Each slow‐slip event causes on average 10–20 cm shearing over several square kilometers. Most events are associated with reported casing deformation, but only about half display jointly occurring induced seismicity of magnitude . The cumulative seismic moment released by the detected slow‐slip events between 2017 and 2023 is orders‐of‐magnitude larger than that released by the approximately 2,300 earthquakes between 2005 and 2023. Although detected slow slip presents limited risk to surface infrastructure, it poses an economic risk to subsurface infrastructure such as hydrocarbon boreholes.