Reactivation Potential of Intraplate Faults in the Western Quebec Seismic Zone, Eastern Canada

Abstract

The intraplate western Quebec seismic zone (WQSZ) in eastern Canada experiences moderate seismicity that mainly results from reactivation of inherited structures under the present-day, NE-SW-striking regional maximum horizontal stress (SH) and, possibly to a minor extent, through stress perturbations in response to glacio-isostatic adjustment. This work comprises the first numerical stress simulation-based study that predicts the preferred spatial distribution, trends, and sense of slip of contemporary fault reactivation, which may have implications for possible fault segmentation patterns in the WQSZ. We show that mostly NNW-SSE to NW-SE-striking faults exhibit the highest slip tendency values. Spatial patterns of slip tendency and kinematics of reactivation are consistent with the observed seismicity. In an area where Quaternary-active faults have yet to be systematically identified, we have narrowed down areas to focus on for more detailed, future neotectonic investigations that could provide sound foundation for seismic hazard assessments. This study demonstrates the applicability of slip tendency analysis to identifying potentially active faults in stable continental regions worldwide.

Coseismic Coulomb Stress Changes on Intraplate Faults in the Western Quebec Seismic Zone, Canada: Implications for Seismic Hazards

“…The magnitude estimates based on the extent of positive coulomb stress changes on the receiver fault 'RF-T1' can provide parameters for future seismic hazard and risk modeling in the Témiscaming area. However, the potential for a significant earthquake in the Cornwall-Massena and Ladysmith areas cannot be entirely ruled out, as these are obviously seismically active areas, and since relatively high slip tendency values have also been measured on the NW-SE striking faults in these areas (Rimando and Peace, 2021).…”

“…), and while this method has been previously applied in the nearby Charlevoix Seismic Zone in Quebec (Fereidoni and Atkinson, 2015), it was done in the context of relating modern seismicity to a large historic earthquake in the 1600s and not with the goal of identifying possible future rupture zones. In this study, we analyze the Coulomb stress changes caused by seismicity in the past 100 years to nearby faults in the WQSZ with a focus on faults that exhibit a relatively high slip tendency (Rimando and Peace, 2021). The characteristics of faults that appear to be promoted to failure can provide input parameters for future seismic hazard and risk modeling, which may have implications for urban planning, seismic design, and managing industrial operations that could alter the stress states in the area.…”

“…(Lamontagne et al, 2020). Note that the preexisting normal faults on this map are optimally oriented for reactivation as reverse faults (Rimando and Peace, 2021).…”

“…The seismicity in the WQSZ is attributed primarily to the reactivation of pre-existing structures (Rimando and Peace, 2021) under the contemporary tectonic stress field (Mazzotti & Townend, 2010;Reiter et al, 2014; Snee & Zoback, 2020). Previous regional numerical stress analyses (e.g., Rimando and Peace, 2021) have shown that the mainly reverse/thrust faulting on mostly NW-SE striking faults in the WQSZ, as indicated by earthquake focal mechanisms, is compatible with the present-day NE-SW maximum horizontal stress orientation (SHmax) that is associated with spreading along the Mid-Atlantic Ridge (Richardson, 1992).…”

Tectono-Geomorphic Analysis in Low Relief, Low Tectonic Activity Areas: Case Study of the Temiskaming Region in the Western Quebec Seismic Zone (WQSZ), Eastern Canada

“…This region has experienced a high number of seismic events with an average seismicity between 2.5 and 7 [11]. An understanding of past earthquakes in Eastern Canada is important for industrial and exploration projects [11][12][13][14][15], and for a better understanding of the sources of the current seismicity in relation to the regional stress fields [14][15][16][17][18][19][20] Paleoseismic investigations can definitively improve earthquake hazard assessment not only in areas characterized by high seismic activity such as Italy [21][22][23][24], Japan [25][26][27], or New Zealand [28][29][30][31], but also in intracratonic areas where shedding light on the history of past shaking is more challenging [32][33][34][35][36]. However, where recurrence intervals are long or surface displacements are not significant, it can be difficult to identify past ruptures, and it is therefore difficult to target sites for trenching, shallow seismic profiling, or other detailed paleoseismic investigations.…”