SUMMARY MAP OF EASTERN CANADIAN SEISMIC STATIONS AND SEISMICITY JANUARY 2003 TO SEPTEMBER 2005

DRYSDALE, J.A., HALCHUK, S., LEHMANN, S., and PECI, V., Geological Survey of Canada, Natural Resources Canada, 7 Observatory Crescent, Ottawa, ON, CANADA, K1A 0Y3, drysdale@seismo.nrcan.gc.ca.

During the period January 2003 to September 2005, there were approximately 1980 earthquakes, 2099 blasts and 178 mine-related events located in eastern Canada. The distribution of earthquakes is similar to events located in the past, with the majority of earthquake activity being along the St. Lawrence and Ottawa valleys in the south and Wager Bay and Baffin Island regions in the north. Although blasts are not routinely located, an attempt has been made during the past seven years to locate many, but not all, blasts greater than magnitude 2.5. These data will provide information for blast/earthquake discrimination, location accuracy and wave propagation. Larger mine-related events were also located and small rockbursts were analyzed when requested by the mine. During the past 4 years the seismic network in Ontario and western Quebec has been expanded significantly though the addition of 49 POLARIS stations. Also, during the summer of 2004, three new POLARIS stations were installed on the northeastern shore of Hudson Bay and another four in the summer of 2005. Although the purpose of these stations was not primarily for earthquake monitoring, their installation has resulted in a lower detection threshold and better location capabilities in these regions. Of particular interest are the James Bay and Wager Bay regions, where more than 190 small magnitude earthquakes have been recorded that would have previously been undetected.