Ground Motion Relations Calibration
The prediction of ground motion levels (expressed in terms of Peak Ground Velocity PGV) at distance R from the seismic source with specified characteristics (Potency P or Energy E) is important both for evaluation of possible damage (strong ground motion) and for analysis of sensitivity of seismic systems (weak ground motion).
The form of the PGV (R, P or E) relation we use takes into account the effect of a finite size seismic source, providing approximately constant PGV in the vicinity of the source – there are not infinite ground motions at the source! Calibration of the ground motion relation PGV (R, P or E) includes the following steps:
- selection of sites which are situated in the vicinity of support units of concern;
- estimation of waves amplification/suppression effects of the sites using small and medium size events;
- selection of a suitable data set of large events (both in terms of large P, E and PGV)
- fitting of the PGV (R, P or E) relation.
The conditions above for selecting the sites and events are relaxed if the weak ground motion relation is of interest.