Roughly uniform distribution of records w.r.t. magnitude and distance. New data contributes significantly
to large magnitude and near-field ranges.
Correct records using an elliptical filter selecting an appropriate low-frequency cut-off, fL, individually for
each record using the criterion of Bommer et al. (1998).
Plot PGA against fL for two pairs of horizontal components of ground motion from the BOL and DZC
stations from the Duzce earthquake (12/11/1999). Record from BOL was recorded on a GSR-16 digital
accelerograph and that from DZC was recorded on a SMA-1 analogue accelerograph. Find PGA is stable
for low-frequency cut-offs up to at least 0.4Hz for the selected records.