Moment Magnitude Computation and Instrumentation Selection for Induced-Seismicity Traffic Light Systems

Summary We perform an in depth analysis on the size of recent induced seismicity occurring in Duvernay formation. The dataset consists of events recorded between Aug 31, 2014 and March 7, 2015 near Fox Creek, Alberta. We calculate moment magnitude (Mw) with the commonly used spectral fitting technique, and examine the relation between moment magnitude and local magnitudes (ML) reported by Natural Resources Canada (NRCAN) for this seismic sequence. Attenuation is a key factor in ground-motion modeling, and can influence the moment magnitudes estimated from observed motions. As part of this study, we investigate the regional attenuation attributes of Fox Creek earthquakes and calculate their source parameters. Instrumentation selection can have a significant impact on the results and costs of monitoring. In this study, we also evaluate the suitability of geophones and seismometers for moment magnitude estimation at local and regional distances. We find that seismometers are able to estimate reliable moment magnitudes over much larger distance and magnitude ranges resulting in fewer required stations for induced seismicity monitoring applications.