An improved method for the analysis of the completeness of a seismic catalogue

SummaryWe present a procedure to identify the incompleteness of a seismic catalogue which is an enhancement of a method we previously developed and applied. It consists of three steps : aftershock and swarm removal, measure of the relative completeness, and estimate of the absolute completeness. We assume that the independent events form a stationary Poisson process and take the nonstationarities of the recorded seismic sequences as a measure of relative completeness. Under the further assumption that the subcatalog consisting of the largest events which occurred most recently is absolutely complete, we may evaluate the true occurrence rate for all magnitudes. We analyse the sequence of earthquakes which occurred in Calabria and Sicily and compare the results with those previously obtained.