- 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 ML from KNMI are equivalent to Mw 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 repi rather than rhypo 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 c5 and c6 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
- Examine intra- and inter-event residuals. Find no trends in inter-event residuals w.r.t. Mw but some
patterns in intra-event residuals w.r.t. repi, which relate to unusual velocity structure above gas reservoir.