Calibration of Local Magnitude MLin the Azores Archipelago Based on Recent Digital Recordings

The development of the digital seismic network in the Azores Archipelago during recent years made it possible to obtain the amplitudes (waveform) of recorded motion in a large set of stations. With this new data, maximum amplitudes of the Wood Anderson seismograph are computed, for each station/ component, which, together with epicentral distances, allows for the estimation of local magnitude ML. We used data recorded in 8 digital permanent three-component stations, with inter-station’s distances up to 300 km, in the period June 1998 – June 2000, corresponding to a set of 1315 events with magnitude (ML or MD) 2