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Stress Chatter via Fluid Flow and Fault Slip in a Hydraulic Fracturing‐Induced Earthquake Sequence in the Montney Formation, British Columbia
Author(s) -
Peña Castro A. F.,
Roth M. P.,
Verdecchia A.,
Onwuemeka J.,
Liu Y.,
Harrington R. M.,
Zhang Y.,
Kao H.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl087254
Subject(s) - geology , aftershock , seismology , hydraulic fracturing , seismometer , slip (aerodynamics) , fluid pressure , differential stress , shear stress , fluid dynamics , geotechnical engineering , deformation (meteorology) , physics , mechanics , engineering , mechanical engineering , oceanography , materials science , composite material , thermodynamics
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 Formation, northeast British Columbia, and stress modeling to examine the spatiotemporal evolution of the 30 November 2018 M w 4.2 (M L 4.5) hydraulic fracturing‐induced earthquake sequence. The isolated occurrence of the mainshock at a depth of ∼ 4.5 km in the crystalline basement 2 days following injection onset at ∼ 2.5 km depth suggests direct triggering by rapid fluid pressure increase via a high‐permeability conduit. Most aftershocks are in the top 2 km sedimentary layers, with focal mechanisms indicating discrete slip along subvertical surfaces in an ∼ 1 km wide deformation zone. Aftershock distribution is consistent with static stress triggering from the M w 4.2 coseismic slip. Our analysis suggests that complex hydraulic and stress transfer between fracture networks needs to be considered in induced seismic hazard assessment.