Dr. John F. Cassidy

Earthquake Seismologist

Head of the Earthquake Seismology Section, Project Leader of Assessing Earthquake Geohazards

Natural Resources Canada

Current research and/or projects

John Cassidy is a senior Research Scientist with Natural Resources Canada. His research involves all aspects of earthquake hazard studies to help mitigate the impact of future earthquakes in Canada. Current research activities include: mapping movement along faults; mapping the earthquake-generating stress-field; obtaining more accurate earthquake locations; studying what controls local variations in earthquake ground shaking; and mapping earth structure using earthquake waves (with applications to resource evaluations). These research results are used to inform national codes and standards (e.g., the National Building Code of Canada, bridge codes, dam codes) and  allow for the development of accurate earthquake scenarios in Canada. John is an Adjunct Professor at the University of Victoria where he teaches courses and supervises graduate students in earthquake research.

Professional activities / interests

John served as a member of the Canadian Association of Earthquake Engineers Chile Earthquake Reconnaissance Team that travelled to Chile after the devastating magnitude 8.8 earthquake in 2010. He travelled through the hardest-hit parts of Chile examining bridges, hospitals and schools and comparing damage to the observed ground shaking levels.  He continues to work with scientists and engineers in Chile to strengthen research partnerships and better understand the hazards associated with subduction earthquakes in Chile, Canada, and elsewhere.

John serves on a number of local, national, and international steering committees and editorial committees, and is a regular reviewer of research proposals and journal articles.

Education and awards

Ph.D., Dept. of Geophysics and Astronomy, University of B.C. (1991)

M.Sc., Dept. of Geophysics and Astronomy, University of B.C. (1987)

B.Sc. (Honours Physics), Dept. Of Physics and Astronomy, University of Victoria (1982)

Key publications

2016

Farahbod, A.M., Calvert, A.J., Cassidy, J.F., and Brillon, C. (2016). Coda Q in the northern Cascadia subduction zone, Bulletin of the Seismological Society of America (in press).

Farahbod, A.M., and Cassidy, J.F. (2016). Seismic Attenuation in the Anahim Volcanic Belt and Adjacent Regions of British Columbia, Geological Survey of Canada, Open File 8030, 50 pp, (in press).

2015

Bird, A.L., Cassidy, J.F., Kao, H., Leonard, L.J., Allen, T.I., Nykolaishen, L., Dragert, H., Hobbs, T.H., Farahbod, A.M., Bednarski, J.M., James, T., Lamontagne, M., Shan, S.-J., Hyndman, R.D.,  Fine, I.V., Cherniawsky, J.Y., Brillon, C.D.,  Wang, K., and Rogers, G.C. (2015). The October 2012 Magnitude (Mw) 7.8 Earthquake offshore Haida Gwaii, Canada, Summary of the Bulletin of the International Seismological Centre, July-December 2012, Vol. 49, Issue 7-12, 41-72.

Crow, H., Hunter, J., Brewer, K., Brillon, C., Allen, T., Cassidy, J.F., and Hayek, S. (2015). Soft soil response investigations in Kitimat, BC – Some preliminary results, Paper 94054, Proceedings of the 11th Canadian Conference on Earthquake Engineering, 10 pp.

Cassidy, J.F., Rogers, G.C., Adams, J., and Halchuk, S. (2015). Canadian strong motion monitoring and recent datasets from Natural Resources Canada, Paper 93832, Proceedings of the 11th Canadian Conference on Earthquake Engineering, 9 pp.

Molnar, S.E., Ventura, C. E., Finn, W.D.L., Cassidy, J.F., Olsen, K.B., and Dosso, S.E. (2015). Long-period response spectra of large scenario earthquakes in British Columbia, Paper 93795, Proceedings of the 11th Canadian Conference on Earthquake Engineering, 8 pp.

Farahbod, A.F., Kao, H., Cassidy, J.F., and Walker, D.  (2015). How did hydraulic-fracturing operations in the Horn River Basin change seismicity patterns in Northeast British Columbia, Canada, The Leading Edge (Invited), June 2015, 658-663, doi: 10.1190/tle34060658.1.

James, T., Cassidy, J.F., Rogers, G.C., and  Heusseler, P., (2015). Introduction to the Special Issue on the 2012 Haida Gwaii and 2013 Craig Earthquakes at the Pacific-North America Plate Boundary (British Columbia, Canada and Alaska, United States), Bulletin of the Seismological Society of America, 105, 2B, 1053-1057, doi: 10.1785/0120150044.

Hobbs, T.E., Cassidy, J.F., and Dosso, S.E. (2015). Rupture Process of the Mw 7.8 2012 Haida Gwaii Earthquake from an Empirical Green’s Function Method, Bulletin of the Seismological Society of America, 105, 2B, 1219-1230, doi: 10.1785/0120140175.

Gosselin, J.M., Cassidy, J.F., and Dosso, S.E. (2015). Shear Wave Velocity Structure in the Vicinity of the 2012 Mw 7.8 Haida Gwaii Earthquake from Receiver Function Inversion, Bulletin of the Seismological Society of America, 105, 2B, 1106-1113, doi: 10.1785/0120140171.

Hobbs, T.E., Cassidy, J.F., Dosso, S.E., and Brillon, C. (2015). Coulomb stress changes following the Mw 7.8 2012 Haida Gwaii, Canada earthquake: Implications for seismic hazard, Bulletin of the Seismological Society of America, 105, 2B, 1253-1264, doi: 10.1785/0120140158.

Cassidy, J.F. (2015). The 2004 Sumatra Earthquake and Tsunami: Lessons learned in subduction zone science and emergency management for the Cascadia Subduction Zone, Pure and Applied Geophysics, 172, No.3-4, 221-234, doi: 10.1007/s00024-014-1023-4.

Farahbod, A.M., Kao, H., Walker, D., and Cassidy, J.F. (2015). Investigation of Regional Seismicity Before and After Hydraulic Fracturing in the Horn River Basin, Northeast British Columbia, Canadian Journal of Earth Sciences52, 1-11, doi: 10.1139/cjes-2014-0162.

2014

Farahbod, A.F., Cassidy, J.F., Kao, H., and Walker, D.  (2014). Collaborative Studies of Regional Seismicity in Northeast British Columbia, Canadian Society of Exploration Geophysicists Recorder, 39, no. 9, 40-44.

Dosso, S.E., Leonard, L.J., Dettmer, J., Cassidy, J.F., and Wang, K. (2014). Geophysics at the University of Victoria, Canadian Society of Exploration Geophysicists Recorder, 39, no. 7, 51-52.

Kim, H.S., Cassidy, J.F., Dosso, S.E., and Kao, H. (2014). Mapping crustal structure of the Nechako-Chilcotin plateau using teleseismic receiver function analysis, Canadian Journal of Earth Sciences (Invited), 51, 407-417, doi:10.1139/cjes-2013-0147.

Cassidy, J.F., Rogers, G.C., and Hyndman, R.D. (2014). An Overview of the October 28, 2012 Mw 7.7 Earthquake in Haida Gwaii, Canada: A Tsunamigenic Thrust Event Along a Predominantly Strike-Slip Margin, Pure and Applied Geophysics (Invited), Feb. 2014, ISSN: 0033-4553 (Print) 1420-9136 (Online),171, xxx-yyy, doi:10.1007/s00024-014-0775-1.

Molnar, S., Cassidy, J.F., Olsen, K.B., Dosso, S.E., and He, J., (2014). Earthquake ground motion and 3D Georgia Basin amplification in SW British Columbia: Shallow blind-thrust scenario earthquakes, Seismological Society of America, 104, 321-335, doi:10.1785/0120130116.

Molnar, S., Cassidy, J.F., Olsen, K.B., Dosso, S.E., and He, J., (2014). Earthquake ground motion and 3D Georgia Basin amplification in SW British Columbia: Deep Juan de Fuca Plate events, Bulletin of the Seismological Society of America, 104, 301-320, doi:10.1785/0120110277.

Kao, H., Shan, S.-J., Cassidy, J.F., and S. Dehler (2014). Crustal Structure of the Gulf of St. Lawrence, Atlantic Canada: Preliminary Results From Receiver Function Analysis, Geological Survey of Canada, Open File 7456, 48 pp, doi:10.4095/293724.

2013

Cassidy, J.F. (2013). Earthquake, Encylopaedia of Natural Hazards, Bobrowsky, Peter T. (Ed.) 2013, XLI, 1135 p. 479 illus., ISBN 978-90-481-8699-0, Springer Publications, p. 208-223.

Meighan, L., Cassidy. J.F., Mazzotti, S., and Pavlis, G.L. (2013). Microseismicity and tectonics of the Southwest Yukon using a local dense seismic array, Bulletin of the Seismological Society of America, 103, 3341–3346, doi: 10.1785/0120130068

Brillon, C., Cassidy, J.F., and S.E. Dosso (2013). Onshore/Offshore Structure of the Juan de Fuca plate in northern Cascadia from Bayesian Receiver Function Inversion, Bulletin of the Seismological Society of America, 103, 2914–2920, doi: 10.1785/0120120310.

James, T., Rogers, G.C., Cassidy, J.F., Dragert, H., Hyndman, R., Leonard, L., Nykolaishen, L., Riedel, M., Schmidt, M., and Wang, K. (2013). Field studies target the October 27, 2012 magnitude 7.7 Haida Gwaii thrust earthquake, EoS Transactions of the American Geophysical Union, 94 (22), 197-198.

Molnar, S., Dosso, S.E., and Cassidy, J.F. (2013). Uncertainty of linear earthquake site amplification via  Bayesian inversion of surface wave seismic data, Geophysics, Vol. 78, No. 3 (May-June, 2013), P. WB37-WB48, 10.1190/GEO2012-0345.1.

2012

Balfour, N., Cassidy, J.F., and Dosso, S.E. (2012). Identifying active structures using double-difference earthquake relocations in Southwest British Columbia and the San Juan Islands, Washington, Seismological Society of America, 102, 639-649, doi: 10.1785/0120110056.

Chiauzzi, L., Cassidy, J.F., Kutyn, K., Masi, A., Mucciarelli, M., Traber, J., Ventura, C., and Yao, F. (2012). Estimate of the Fundamental Period of Reinforced Concrete Buildings: Code Provisions vs Experimental Measures in Victoria and Vancouver (BC, Canada). Proceedings of the 15th World Conference on Earthquake Engineering, Paper 3033, 10 pp.

2011

Balfour, N., Cassidy, J.F., and Dosso, S.E. (2011). Crustal anisotropy in the forearc of the Northern Cascadia subduction zone, British Columbia, Geophysical Journal International, doi: 10.1111/j.1365-246X.2011.05231.x.

Mazzotti, S., Leonard, L.J., Cassidy, J.F., Rogers, G.C., and Halchuk, S. (2011). Seismic Hazard in Western Canada from GPS Strain Rates Vs. Earthquake Catalog, Journal of Geophysical Research, VOL. 116, B12310, doi:10.1029/2011JB008213.

2010

Cassidy, J.F., Rogers, G.C., Lamontagne, M., Halchuk, S., and Adams, G. (2010). Canada=s earthquakes: Athe Good, the bad, and the ugly@, Geoscience Canada, 37, 1-16.

Cassidy, J.F., Balfour, N., Hickson, C., Kao, H., White, R., Caplan-Auerbach, J., Mazzotti, S., Rogers, G.C., Bird, A., Al-Khoubbi, I., Esteban, L., and Kelman, M. (2011). The 2007 Nazko, British Columbia, earthquake sequence: Injection of magma deep in the crust beneath the Anahim Volcanic Belt, Bulletin of the Seismological Society of America, 101, 1732-1741, doi: 10.1785/0120100013.

Molnar, S., Dosso, S.E., and Cassidy, J.F. (2010). Bayesian inversion of microtremor array dispersion data in southwestern British Columbia, Geophysical Journal International, 183, 923-940. DOI: 10.1111/j.1365-246X.2010.04761.x.

Balfour, N., Cassidy, J.F., and Dosso, S.E. (2011). Mapping crustal stress and strain in Southwest British Columbia, Journal of Geophysical Research, VOL. 116, B03314, 11 PP., 2011, doi:10.1029/2010JB008003.

2009

Mucciarelli, M., Herak, M., and Cassidy, J.F. (editors) (2009). Increasing Seismic Safety by Combining Engineering Technologies and Seismological Data, Springer, 382 p., ISBN: 978-1-4020-9193-3.

2008

Bilich, A., Cassidy, J.F., and K.M. Larson (2008). GPS as a Strong Motion Seismometer: Application to the 2002 Mw=7.9 Denali Fault Earthquake, Bulletin of the Seismological Society of America, 98, 593-606, doi: 10.1785/0120070096.

2006

Molnar, S., and Cassidy, J.F. (2006). A comparison of site response techniques using earthquakes and microtremors, Earthquake Spectra, 22, 169-188.

2004

Currie, C.A., J.F. Cassidy, R.D. Hyndman, and M.G. Bostock (2004). Shear wave anisotropy beneath the Cascadia Subduction Zone and western North American craton, Geophys. J. Int., 157, 341-353, doi:10.1111/j.1365-246X.2004.02175.x.

Molnar, S., Cassidy, J.F., and S.E. Dosso (2004). Site response in Victoria, BC from spectral ratios and 1-D modeling, Bulletin of the Seismological Society of America, 94, 1109-1124.

Molnar, S., Cassidy, J.F., and S.E. Dosso (2004). Comparing intensity variation of the 2001 Nisqually earthquake to geology in Victoria, British Columbia, Bulletin of the Seismological Society of America, 94, 2229-2238.

Cassidy, J.F., and G.C. Rogers (2004). The M=7.9 Denali Fault earthquake of 3 November 2002: Felt reports and unusual effects across Western Canada, Bulletin of the Seismological Society of America, 94, S53-S57.

2000

Cassidy, J.F., G.C. Rogers, and F. Waldhauser (2000). Characterization of active faulting beneath the Strait of Georgia, British Columbia, Bull. Seism. Soc. Am.,  90, 1188-1199.

1999

Cassidy, J.F., and G.C. Rogers (1999). Seismic site response in the greater Vancouver, British Columbia area: Spectral ratios from moderate earthquakes, Can. Geotech. J., 36, 195-209.

Atkinson, G.M.,  and J.F. Cassidy (2000). Integrated use of seismograph and strong motion data to determine soil amplification: Response of the Fraser Delta to the Duvall and Georgia Strait, Bull. Seism. Soc. Am, 90, 1028-1040.

1998

Cassidy, J.F., R.M. Ellis, C. Karavas, and G.C. Rogers (1998). The northern limit of the subducted Juan de Fuca plate system, J. Geophys. Res., 103, 26949-26961.

1996

Cassidy, J.F., and M.G. Bostock (1996). Shear-wave splitting above the subducting Juan de Fuca plate, Geophys. Res. Lett., 23, 941-944.

1995

Cassidy, J.F. (1995). Rupture directivity and slip distribution for the MS 6.8 earthquake of 6 April 1992, offshore British Columbia: An application of the empirical Green's function method using surface waves, Bull. Seism. Soc. Am., 85, 736-746.

Cassidy, J.F., and G.C. Rogers (1995). The rupture process and aftershock distribution of the 6 April 1992 Ms 6.8 earthquake, offshore British Columbia,  Bull. Seism. Soc. Am., 85, 716-735.

1992

Cassidy, J.F. (1992). Numerical experiments in broadband receiver function analysis, Bull. Seism. Soc. Am., 82, 1453-1474. 

Affiliations

Seismological Society of America – Member

Canadian Association of Earthquake Engineers - Member