A method for estimating the coverage of a seismic network: RESNOM

A new, simple, straightforward, and intuitive method for assessing the coverage of a seismic network, by estimating the minimum measurable magnitude, i.e., the magnitude corresponding to the smallest identifiable, and quantifiable signal, at any point of the region being monitored, is presented. The method takes advantage of the knowledge implicit in the magnitude determination scheme routinely used by the network, and uses the minimum measurable value of the parameter used at each seismic station to quantify the magnitude, which for different magnitudes may be maximum amplitude, duration, energy, etc. The method is illustrated by application to the RESNOM seismological network that monitors the seismically active region of north-western Baja California, Mexico, and uses synthetic Wood-Anderson seismograms to estimate M_L for small earthquakes. The results, besides identifying regions where more or better seismographic stations are needed, indicate that the observed groupings and gaps in the epicentral distribution are real features of the seismic processes in the region and not artifacts due to coverage.