Strong evidence for non-similar earthquake source scaling in central Italy

The scaling of earthquakes of the Central Apennines (Italy) is investigated using broadband seismograms from the Colfiorito sequence (4 <= M-W <= 6). Our results are not consistent with self- similar scaling, and can be described by the following relationship: M-0 alpha f(c)(-(3+epsilon)), where epsilon = 1.7 +/- 0.3. We speculate that dynamic fault lubrication by fluid pressurization may be responsible for such extreme behavior, and use our results for the calibration of a weak-motion-based predictive relationship for the ground motion (M-W <= 4.1) up to M-W similar to 6 for this region.