- Ground-motion model is:
- Response parameter is acceleration for 5% damping.
- Data from 18 instruments on ground surface.
- All station have roughly 180 ≤ V
_{s,30}≤ 210m∕s. Do not include explicit site response term because site conditions at all stations not available. - Assume that M
_{L}from KNMI are equivalent to M_{w}in the magnitude range considered. - Derive model for comparison with model from stochastic simulations, for use within a risk assessment, and to constrain the aleatory variability components.
- Records of induced seismicity within gas reservoir (thickness 150–300m) located at depth of 3km.
- Use r
_{epi}rather than r_{hypo}because all earthquakes at same depth. - Earthquakes either normal or strike-slip but reliable fault-plane solutions not available so do not consider the effect of mechanism.
- Do not include term for anelastic attenuation because of limited distance range.
- Find unphysical combinations of c
_{5}and c_{6}at longer periods. Hence regress for all periods simultaneously with the constraint of common values for these two coefficients. - Do not report coefficients.
- Find model fits data well but that it would not extrapolate reliably to larger magnitudes because of linear magnitude scaling.
- Examine intra- and inter-event residuals. Find no trends in inter-event residuals w.r.t. M
_{w}but some patterns in intra-event residuals w.r.t. r_{epi}, which relate to unusual velocity structure above gas reservoir.