The Overlap of Aftershock Coda Waves and Short-Term Postseismic Forecasting

Abstract

The elaboration of reliable forecasting in the first hours after large shocks, very useful for the postseismic management, is strongly affected by the huge incompleteness of seismic catalogs. The deficit of observed events, in the first part of aftershock sequences, can be naturally attributed to different mechanisms such as the inefficiency of the seismic network as well as the overlap of seismic records. In this study we show that short-term aftershock incompleteness can be explained only in terms of the second mechanism whereas it is only weakly affected by the quality of the instrumental coverage. Indeed, we show that larger deviations from the Gutenberg-Richter law and the Omori-Utsu law can be found in regions with a higher seismic network efficiency. We use these results to develop an incomplete Epidemic-Type Aftershock Sequence model able to reproduce statistical features in time and magnitude of recorded aftershocks.