The Importance, Challenges and Applications of Old Seismic Data for Modern Seismic Hazard Analysis
Most of Canada’s largest known earthquakes occurred during a period when mechanical seismometers and paper recordings and notes were “state-of-the-art”. These significant earthquakes (that dominated the development of seismic hazard maps) include the 1929 M7.2 Grand Bank’s earthquake off Newfoundland, 1933 M7.3 Baffin Bay earthquake, the 1946 M7.3 Vancouver Island earthquake and the 1949 M8.1 Haida Gwaii earthquake. Re-evaluating these events using modern analysis techniques is critical to our assessment of earthquake hazards in a variety of tectonic environments across Canada. This presentation highlights the importance of working with historical data (paper seismograms, but also original notes, photographs, etc.) and summarizes some applications and challenges of working with these old records. We describe some of the analysis techniques that have been utilized and several that still need to be applied – including the use of modern calibration events and empirical Green’s functions for more accurate source studies.
Events studied to date include the 1918 Vancouver Island earthquake (M 7.0), 1925 Charlevoix (M 6.2), 1929 Grand Banks (M 7.2), 1933 Baffin Bay (M 7.3), 1940 Richardson Mtns (M 6.2 and 6.5), 1944 Cornwall-Massena (M 5.8), 1946 Vancouver Island (M 7.3), 1949 Queen Charlotte Islands (M 8.1), the 1953-1957 MacKenzie Mtns. sequence (5 events, M 5.5-6.5). This work has: 1) made important contributions to our assessment of seismic hazard in Canada; and 2) demonstrated the importance of digitizing, storing and preserving legacy data.
Presenting Author: John F. Cassidy
Additional Authors
John F Cassidy john.cassidy@canada.ca Natural Resources Canada, Sidney, British Columbia, Canada Presenting Author
Corresponding Author
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Allison L Bent allison.bent@canada.ca Natural Resources Canada, Ottawa, Ontario, Canada |
The Importance, Challenges and Applications of Old Seismic Data for Modern Seismic Hazard Analysis
Category
Back to the Future: Innovative New Research with Legacy Seismic Data