A Preliminary Analysis of Local and Regional Earthquakes Recorded by a Single Digital Broadband Seismic Station, AQU, Central Italy

Abstract

A new digital three component broadband seismic station has been installed last year in Villavallelonga (VVLD), Central Italy, equipped with a Guralp CMG- 3T sensor, at 120 seconds and sampling at 50 Hz. The station is part of the new digital network developed by Istituto Nazionale di Geofisica e Vulcanologia in Rome, but actually integrated in the Italian Seismographic Network. VVLD sends data to the Data Center in Rome using wired digital communication. It implements a 24 bit AD converter with an effective dynamic range of 140 dB. This combined with the characteristics of the broadband sensor, give the possibility to construct a good quality dataset of local and regional earthquakes. This study is a preliminary analysis of the collected data, aimed to emphasize the usefulness of single-station broadband data for local and regional seismicity in general, besides of path calibrations. We selected 20 events in the database of about 1000, within a distance range from 50 to 1300 km and magnitudes greater than 3.0, from May 1 to August 31, 2001. We calibrated the local structure around the station, since at very short epicentral distances the effects of the structure and source are easily separated,and finally we used these results to enable the waveform inversions at larger distances.