- Ground-motion model is:
where Y is in cm∕s2, c0 = -0.13, c1 = 0.77, b = -2.63, σintra = 0.22 (intra-event), σinter = 0.19
(inter-event) and σtotal = 0.29 (total) for the Graham area; c0 = -1.14, c1 = 0.94, b = -1.78, σintra = 0.39
(intra-event), σinter = 0.13 (inter-event) and σtotal = 0.41 (total) for the Septimus area; and c0 = -0.78,
c1 = 0.88, b = -2.12, σintra = 0.31 (intra-event), σinter = 0.27 (inter-event) and σtotal = 0.41 (total) for
the combined dataset.
- Correct data to V s,30 = 760m∕s using linear site factors of Boore et al. (2014). Estimate V s,30 using the
horizontal-to-vertical ratio of the Fourier amplitude spectra. All sites classified as either NEHRP categories
C or D.
- Data of potentially-induced earthquakes from wastewater disposal and hydraulic fracturing recorded by
networks operated by energy companies and stations of the Canadian National Seismic Network in Montney
Play (British Columbia, Canada) area.
- Correct data for instrument response and then high-pass Butterworth filter the data with corner frequency
of 0.1Hz. Corner frequency chosen from qualitative analysis to remove long-period trends from records.
- Most data from M < 2 and focal depths between 3 and 4km. No events with depth > 8km.
- Do not include anelastic attenuation term in model because data from relatively short distances. Do
not include effective depth parameter to model saturation because earthquakes are small and effect not
observed in data.
- Examine residuals w.r.t. M and R. For the Graham area find no trends but for the Septimus area find
evidence for significant under- and over-prediction at some distances.
- Find that in general ground motions in both areas are similar for M ≥ 2.5. Therefore, derive model for
combined data but only using data from M ≥ 2.5. No trends seen in residuals for this combined model
even for the Septimus data.