Special Report 104

Special Report 104

SPE 104

Initial Seismic Hazard Assessment for the Induced Earthquakes Near Fox Creek, Alberta (between January 2013 and January 2016)

Author(s) Schultz, R.J. Nanometrics Inc. Date 2019-11-21

This report assesses the seismic hazard near the town of Fox Creek, Alberta. It is a combined release of two reports produced by Nanometrics Inc., with input from Western University, using public and private ground motion data. These reports include probabilistic seismic hazard assessments for the years 2013 through 2015 and ShakeMaps of the largest magnitude events induced between January 2013 and January 2016. The hazard forecasts assume earthquake rate and location models based on annually binned catalogued events, regionally calibrated ground motion prediction equations, and tectonic considerations of maximum magnitude.

The results of this analysis suggest significant change (1–2 orders of magnitude) to the prior background hazard estimates for various spectral periods (0.1–5 s). Specifically, hazard maps at 0.04% chance of exceedance in 1 year reach 10–20% of standard gravity in expected peak ground acceleration at the town of Fox Creek. Deaggregation of the seismic hazard maps suggests much of the hazard in forecast scenarios is the result of the potential occurrence of earthquakes of Mw >5. In addition to probabilistic forecasts, ShakeMaps were developed for events larger than 3.5 Mw. Instrumental intensities from these events range between III and IV in Fox Creek, which is consistent with reports of felt ground motion.

This is preliminary work and is superseded by Short-Term Hindcasts of Seismic Hazard in the Western Canada Sedimentary Basin Caused by Induced and Natural Earthquakes (https://doi.org/10.1785/0220180285).

Schultz, R. and Nanometrics Inc. (2019): Initial seismic hazard assessment for the induced earthquakes near Fox Creek, Alberta (between January 2013 and January 2016); Alberta Energy Regulator / Alberta Geological Survey, AER/AGS Special Report 104, 115 p.