Performances of the Italian Seismic Network, 1985-2002: the hidden thing

Abstract

<p><span style="line-height: 0px;"><strong><br /></strong></span></p> <p>Seismic data users and people managing a seismic network take a great interest in the potentiality of the data,</p> <p>with the difference that the former look at stability, the latter at improvements. This work measures the performances</p> <p>of the Italian Telemetered Seismic Network in the years 1985-2002 by defining basic significant parameters</p> <p>and studying their evolution during those years. Then, we deal with the geological methods used to characterise</p> <p>or to plan seismic station deployments in a few cases. Last, we define the gain of the network as the percentage</p> <p>of well-located earthquakes with respect to the total recorded earthquakes. By analysing the distribution</p> <p>of non-located (&laquo;missed&raquo;) earthquakes, we suggest possible actions to take to increase the gain. Results show</p> <p>that completeness magnitude is 2.4 in the average over the analysed period, and it can be as low as 2.2 when we</p> <p>consider non-located earthquakes as well. Parameters such as the minimum recording distance and the RMS of</p> <p>the location decrease with time, reflecting improvements in the location quality. Methods for geologic and seismological</p> <p>characterisation of a possible station site also proved effective. Finally, we represent the number of</p> <p>missed earthquakes at each station, showing that nine stations control more than 50% of all missed earthquakes,</p> <p>and suggesting areas in Italy where the network might easily be improved.</p> <br />