Phases association and earthquake location

We start working on the catalogue available from a previous GNDT project, released in 2001, which covered the period from 1981 to 1996. For this period we kept the original association of the events.

clicca sull'immagine per ingrandirla
For the period 1997-2002, we combined data from several organisations, strongly increasing the spatial resolution all over Italy with respect to the INGV national network alone. We then developed an original algorithm to associate over 2,000,000 P- and S-wave phases recorded at about 700 seismic stations. The new catalogue contains 81,797 located events, out of the 136,850 recorded. Earthquakes have been located by using a simple optimized 1-D velocity model and the Hypoellipse code. A different weighting scheme is applied to the location to optimize hypocentral parameters for earthquakes occurring in regions with different station cover. The statistical parameters of location, including azimuthal gap, errors and final rms are reported in Chiarabba et al. (2005).