A key element in the assessment of induced seismic hazard and risk due to induced
earthquakes in the Groningen gas field is a model for the prediction of ground
motions. Rather than use ground
-
motion prediction equations (GMPEs) with generic
site amplifica
tion factors conditioned on
proxy
parameters such as V
S30
, a field
-
wide
zonation of frequency
-
dependent non
-
linear
amplification factors has been
developed. Each amplification factor is associated with a measure of site
-
to
-
site
variability that captures th
e variation of V
S
profiles and hence amplification factors
across each zone, as well as the influence of uncertainty in the modulus reduction
and damping functions for each soil layer. This model can be used in conjunction with
predictions of response spec
tral accelerations at a reference rock horizon at a depth
of about 80
0 m to calculate fully probabilistic estimates of the hazard in terms of
ground shaking at the surface for a large region potentially affected by induced
earthquakes.