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Andrés Felipe Peña Castro
Public Documents
1
Stress chatter on a fracture network reactivated by hydraulic fracturing
Andrés Felipe Peña Castro
and 7 more
February 18, 2020
Source processes of injection induced earthquakes involve complex fluid-rock interaction often elusive to regional seismic monitoring. Here we combine observations from a local seismograph array in the Montney basin, northeast British Columbia, and stress modeling to examine the spatial and temporal evolution of the 30 November 2018 M 4.5 hydraulic fracturing induced earthquake sequence. The mainshock occurred at ~ 4.5 km in the crystalline basement two days following injection at ~ 2.5 km, suggesting direct triggering by rapid fluid pressure increase via a high-permeability conduit. Most of the aftershocks are located in the top 2 km sedimentary layers, with focal mechanisms indicating discrete slip along sub-vertical surfaces in a ~ 1 km wide deformation zone. Aftershock distribution is also consistent with static stress triggering from the M 4.5 coseismic slip. Our analysis suggests complex hydraulic and stress transfer between fracture/fault networks needs to be considered in induced seismic hazard assessment.