← Back to Sessions

Injection-induced Slow Slip Events in the Canadian Rockies

Description: 

Using satellite-based ground monitoring (InSAR), we show that hydraulic fracturing treatments of the Montney Formation released locked-in stresses near the subsurface deformation front of the Rocky Mountain Fold and Thrust Belt, thereby causing 12 bedding-plane-parallel slow-slip events with magnitudes Mw 4.71 to 5.06 at depths between 1640 and 2410 m. Conversely, human-induced ordinary seismicity concentrates westward. The cumulative seismic moment released by the 12 detected slow slip events between 2017 and 2023 is orders of magnitude larger than that released by the approximately 1800 ordinary earthquakes ML ≥ 1.5 observed between 2005 and 2023. Furthermore, slow slip may occur in the absence of small-to-moderate size ordinary seismicity. Our observations demonstrate the existence of intracontinental slow-slip events within a foreland sedimentary basin on a regional scale. Slip occurs most likely on detachment zones related to marine bioclastic sediments deposited between the fair-weather and storm wave levels, producing alternating competent and incompetent layering. The thin competent layers are load bearing, able to maintain locked-in stresses over geologic time frames; upon their failure, the incompetent layers enable aseismic slow slip. Our findings indicate slow slip may have contributed significantly in the past to the eastward progression of the belt’s subsurface deformation front. Counterintuitively, these hydraulic fracturing treatments may have reduced seismic hazard to surface infrastructure, given the amount of tectonic strain energy released by the slow slip events. Our results also provide insights into geologic and geomechanical factors that could enable the occurrence of aseismic slip within other foreland sedimentary sequences and, plausibly, accretionary wedges near subduction zones.

Session: Mechanistic Insights into Fluid-induced Earthquakes from the Laboratory to the Field - I

Type: Oral

Date: 4/15/2025

Presentation Time: 02:00 PM (local time)

Presenting Author: Mirko

Student Presenter: No

Invited Presentation: Yes

Poster Number:

Authors