eprintid: 1806 rev_number: 14 eprint_status: archive userid: 6 dir: disk0/00/00/18/06 datestamp: 2017-01-03 12:38:52 lastmod: 2019-02-06 09:43:38 status_changed: 2017-01-03 12:38:52 type: article metadata_visibility: show creators_name: Salvaggi, G. creators_name: Ferulano, F. creators_name: Di Bona, M. creators_name: Frepoli, A. creators_name: Azzara, R. creators_name: Basili, A. creators_name: Chiarabba, Claudio creators_name: Ciaccio, M.G. creators_name: Di Luccio, F. creators_name: Lucente, Francesco Pio creators_name: Margheriti, L. creators_name: Nostro, Concetta corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: ENI SpA Divisione Agip, Studi Geofisici, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy corp_creators: Istituto Nazionale di Geofisica, Via di Vigna Murata, Italy title: The October 15, 1996, Reggio Emilia seismic sequence: active compression tectonics in the Po Plain Italy. subjects: MP2 subjects: RIt1 subjects: SHC divisions: IP8 full_text_status: none abstract: We have analysed the seismic sequence that occurred in October 1996 near the town of Reggio Emilia on the southern edge of the Po Plain. The onset of the sequence was marked by a 5.4 moment magnitude main shock, located at 15km depth. The main-shock focal mechanism is a reverse solution with a strike-slip component and the scalar moment is 1.46×1017Nm. We used broad-band digital recordings from a borehole station, located at about 70km from the epicentre, for a spectral analysis in order to estimate attenuation and source parameters for the main shock. In addition, the empirical Green's function method has been applied to evaluate the source time function in terms of both moment rate and stress rate. We infer an asperity-like rupture process for the main shock, as suggested by the short duration of the stress release with respect to the overall duration of the moment rate function. This analysis also allows us to estimate the average dynamic stress drop of the main shock (600bar). We analysed the digital recordings of the temporary local seismic network deployed after the main shock and of a permanent local network maintained by the Italian Petroleum Agency (AGIP). During 15days of field experiments, we recorded more than 800 aftershocks, which delineate a 9km long, NE-elongated distribution, confined between 12 and 15km depth, suggesting that the basement is involved in the deformation processes. 102 focal mechanism of aftershocks have been computed from P-wave polarities, showing mainly pure reverse solutions. We calculate the principal stress axes from a selected population of earthquakes providing a constraint on the stress regime of this part of the Po Plain. The focal mechanisms are consistent with a N-S subhorizontal σ1. All the seismological data we have analysed confirm that this region is undergoing active compressional tectonics, as already inferred from recent earthquakes, geomorphological data and other stress indicators. Moreover, the elongation of the Reggio Emilia aftershock sequence is consistent with the regional direction of the thrust fronts cropping out in the area, suggesting that they are still active. date: 2001-01 date_type: published publication: Geophysical Journal International volume: 144 number: 1 publisher: Oxford University Press pagerange: 1-13 id_number: doi: 10.1046/j.0956-540X.2000.01255.x issn: 0956-540X official_url: http://doi.org/10.1046/j.0956-540X.2000.01255.x access_IS-EPOS: limited owner: Publisher citation: Salvaggi, G. and Ferulano, F. and Di Bona, M. and Frepoli, A. and Azzara, R. and Basili, A. and Chiarabba, Claudio and Ciaccio, M.G. and Di Luccio, F. and Lucente, Francesco Pio and Margheriti, L. and Nostro, Concetta (2001) The October 15, 1996, Reggio Emilia seismic sequence: active compression tectonics in the Po Plain Italy. Geophysical Journal International, 144 (1). pp. 1-13. DOI: https://doi.org/10.1046/j.0956-540X.2000.01255.x