Regressions were carried out on two peak ground acceleration
datasets. The first dataset contains observations from UK
earthquakes ranging from 0.7 to 5.1 ML recorded over distances
of 1-441 km. The second contains data from earthquakes of
similar magnitude (1.9-5.9 ML) compiled by Free et al. (1998) for
north-western Europe. Individual regressions on these datasets
suggest that attenuation in these two regions is similar. In light of
this, the datasets were combined and further regressions carried
out. We compared these results with the relations of Ambraseys et
al. (1996), which are based on data from larger earthquakes and
which have been applied in UK hazard assessments. At magnitudes
less than around 4.9 ML, our relation estimates realistic ground
motions whereas those calculated using Ambraseys et al. (1996)
are signicantly higher. At 5.5 ML and above, our relation predicts
unrealistically high accelerations (up to three times higher than
those estimated using Ambraseys et al., 1996). However, between
4.9-5.0 ML, the two relations coincide for distances of 50 km or
less. This result implies that there is some effect of magnitude that
neither relation accounts for. For the realistic prediction of ground
motion for the entire range of magnitudes, a hybrid approach may be necessar
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