Duration magnitude for the northeastern Italy seismometric network

The computation of new formulae to calculate local magnitude from earthquake coda duration, for each of the 21 stations of the northeastern Italy network. has been performed using 4726 station observations. Introduction of the new formulae into the routine calculus increases the accuracy of local magnitude determinations and assigns new magnitude values to about 7000 events localized by the network in the 1977-1990 period. The present study shows that the old formulae adopted sensibly overevaluate the magnitude determinations of small events and underestimate that of higher quakes.