KEGS Ottawa October Meeting


Ground motions and hazard from Induced Seismicity


Professor Gail Atkinson 
NSERC/TransAlta/Nanometrics Industrial Research Chair in Hazards from Induced Seismicity, 
Western University


Wednesday, October 12th 
4:30 p.m.

Harrison Hall 
Room 177 
601 Booth Street   



In the central U.S. induced-seismicity sources are mostly wastewater disposal wells, whereas in western Canada much of the seismicity is associated with hydraulic fracturing.  A small percentage (~1%) of hydraulic fracture wells will be associated with earthquakes of M>3 in some parts of western Canada.  Due to the shallow focus of induced events, ground motions can be very strong for moderate events very close to the epicentre.  In areas of low-to-moderate seismicity, this can dramatically increase the seismic hazard, particularly for critical infrastructure. The hazard can be modeled by treating the activity as an added seismic source zone in the context of a probabilistic seismic hazard analysis; for a future source, the hazard is conditioned on the probability of activation. The induced-seismicity hazard depends on the activation probability, the magnitude recurrence parameters of the initiated sequence, and the ground-motion prediction equations.   Uncertainty in the value of the key parameters implies large uncertainty (more than an order of magnitude) in the likelihood of strong shaking.



Gail Atkinson, Professor of Geophysics at University of Western Ontario, has devoted her career to working at the engineering-seismology interface.  She has authored more than 200 research articles on the subjects of earthquake ground motions and seismic hazards; among these are well-known prediction equations for ground-motion amplitudes as a function of magnitude and distance that have been used earthquake hazard and risk assessments around the world.  She has been responsible for seismic hazard analyses for dozens of major engineering projects, and has been an active participant on committees responsible for developing seismic design regulations for buildings and critical structures such as dams and nuclear power plants.  She is a member of the U.S. National Earthquake Prediction Evaluation Council.  Professor Atkinson has served as President of the Seismological Society of America, and also as President for the Canadian Geophysical Union.   A current research focus is in the area of induced seismicity.  Professor Atkinson is currently the NSERC/TransAlta/Nanometrics Industrial Research Chair in Hazards from Induced Seismicity.