Micro-seismicity in Alberta recorded by the Canadian Rockies and Alberta Network

Documented seismicity throughout Alberta, Canada has been relatively low in recent history, with fewer than fifteen events (ML > 3.5) recorded by the Geological Survey of Canada (GSC) since 1985. The notable lack of seismicity could be partially attributed to limited or intermittent station coverage in the province. For this reason, the Alberta Geological Survey (AGS) has been involved in a continued effort to maintain, improve and expand regional seismic networks. Broadband seismic data from the Canadian Rockies and Alberta Network (CRANE) and catalog excerpts from the Canadian National Seismic Network (CNSN) were analyzed. Micro-seismic hypocenters were located using Antelope, a software package from Boulder Real Time Technologies, Inc.. Analysis of data from September, 2006 to June, 2010 shows these events are typically naturally occurring or anthropogenic (e.g., mining blasts, which are not usually part of the earthquake catalogs). More than one hundred and twenty natural earthquakes were located in western and central Alberta, with the majority occurring along the Rocky Mountain foothills. During this period, earthquakes magnitudes (ML) ranging from 0.5 to 4.0 were measured and the magnitude of completeness is ~2.8 for this dataset. The substantial number of unreported events suggests that the existing earthquake catalogs, based exclusively on national seismic network stations, are incomplete. The addition of the CRANE dataset has improved the understanding of background seismicity by providing updated hypocenter locations and waveforms of more than thirty previously unrecorded earthquakes. Future endeavors to incorporate data from additional networks would prove invaluable for the identification of emergent trends or induced events.