Faults and Spatial Clustering of Earthquakes Near La Malbaie, Charlevoix Seismic Zone, Canada

Other| March 01, 1997 Faults and Spatial Clustering of Earthquakes Near La Malbaie, Charlevoix Seismic Zone, Canada Maurice Lamontagne; Maurice Lamontagne Geological Survey of Canada 1 Observatory Crescent Ottawa, Ontario (Canada) K1A 0Y3 maurice@seismo.nrcan.gc.ca (M.L.) Search for other works by this author on: GSW Google Scholar Giorgio Ranalli Giorgio Ranalli Department of Earth Sciences and Ottawa-Carleton Geoscience Centre Carleton University Ottawa, Ontario (Canada) K1S 5B6 (G.R.) Search for other works by this author on: GSW Google Scholar Seismological Research Letters (1997) 68 (2): 337–352. https://doi.org/10.1785/gssrl.68.2.337 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation Maurice Lamontagne, Giorgio Ranalli; Faults and Spatial Clustering of Earthquakes Near La Malbaie, Charlevoix Seismic Zone, Canada. Seismological Research Letters 1997;; 68 (2): 337–352. doi: https://doi.org/10.1785/gssrl.68.2.337 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySeismological Research Letters Search Advanced Search Abstract The Charlevoix Seismic Zone (CSZ) is the most active area of Eastern Canada with more than 1,500 earthquakes (magnitudes from about 0.0 ML to 5.0 mbLg) recorded between 1978 and 1995. Earthquakes in a sub-area of the CSZ were analyzed to find evidence of event clustering and of correlations with geological features. Out of 37 events recorded between 1988 and 1995, two triplets had highly-correlated seismic traces and may represent repeated slip on the same fractures. Focal mechanisms of the two largest earthquakes of the sub-area (magnitude mN 4.0 and 3.3) are consistent with the region's predominant reverse faulting regime. For these two events, nodal planes trend WNW-ESE, parallel to lineaments reactivated by the Devonian Charlevoix meteor impact. Thus, these earthquakes do not follow the generally assumed association with the NE-striking paleorift faults. For smaller events, discrete and composite focal mechanisms show variable trends and complex faulting styles including normal faulting and some part of strike-slip motion. This complexity suggests that small magnitude earthquakes might be related to local stress/strength variations, possibly in areas where high pore-fluid pressures are present. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.