Abstract
In this study, surface and subsurface geologicaldata are integrated with seismological data in orderto reconstruct a structural model for theSeptember-October 1997 Colfiorito earthquakes. Theseismic sequence is mainly controlled by two majorSW-dipping normal faults outcropping in the area (M.Pennino-M. Prefoglio and M.Civitella-Preci faults).The activated faults detach, at depth, on a commoneast-dipping low-angle normal fault, the AltotiberinaFault (AF). The AF is interpreted as the base of anactive hangingwall block which is stretching towardNE. The decrease in maximum depth of the earthquakefoci from the Colfiorito area (about 8 km) to theSellano area (about 6 km), suggested by the available seismological data, could be related to the eastward-deepening geometry of the AFdetachment. The seismic fault planes, inferred fromfocal mechanisms and aftershock distributions, arecharacterised by a moderate dip (average 40°)toward SW, which appears to be independent from thepresence of pre-existing thrust planes.
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Accordi, B. and Moretti, A., 1967, Note illustrative del Foglio 131 'Foligno'. Serv. Geol. It. Rome, 57 pp.
Amato, A., Azzara, R.M., Chiarabba, C., Cimini, G.B., Cocco, M., Di Bona, M., Margheriti, L., Mazza, S., Mele, F., Selvaggi, G., Basili, A., Boschi, E., Courboulex, F., Deschamps, A., Gaffet, S., Bittarelli, G., Chiaraluce, L., Piccinini, D. and Ripepe, M., 1998, The 1997 Umbria-Marche, Italy, earthquake sequence: a first look at the main shocks and aftershocks, Geoph. Res. Lett. 25(15), 2861–2864.
Anzidei, M., Baldi, P., Galvani, A., Pesci, A., Hunstad, I. and Boschi, E., 1999, Coseismic displacement of the 27th September 1997 Umbria-Marche (Italy) earthquakes detected by GPS: campaigns and data, Annali di Geofisica 42(4), 597–607.
Bally, A.W., Burbi, L., Cooper, C. and Ghelardoni, R., 1986, Balanced sections and seismic reflection profiles across the central Apennines. Mem. Soc. Geol. It. 35, 257–310.
Barchi, M.R., De Feyter, A., Magnani, M.B., Minelli, G., Pialli, G. and Sotera, B.M., 1998, The structural style of the Umbria-Marche fold and thrust belt, Mem. Soc. Geol. It. 52, 557–578.
Barchi, M.R., Magnani, M.B., Minelli, G., Pialli, G. and Sotera, B.M., 1995, Osservazioni geofisiche sul basamento della regione umbro-marchigiana, Atti GNGTS 14th Conference 2, 709–720.
Boncio, P., 1998, Analisi integrata di dati geologico-strutturali e sismologici per la definizione di un modello sismotettonico in Appennino umbro-marchigiano, PhD Thesis, Università degli Studi di Perugia, Perugia (Italy), 107 pp.
Boncio, P. and Lavecchia, G., 1999, I terremoti di Colfiorito (Appennino umbro-marchigiano) del Settembre-Ottobre 1997: contesto tettonico e prime considerazioni sismogenetiche, Boll. Soc. Geol. It. 118, 229–236.
Boncio, P. and Lavecchia, G., 2000, A structural model for active extension in Central Italy, J. Geodynamics 29, 233–244.
Boncio, P., Bacheca, A., Brozzetti, F. and Lavecchia, G., 1995, Analisi geometrica e cinematica del settore centrale della Catena Narnese-Amerina (Umbria sud-occidentale). Studi Geologici Camerti vol. spec. 1995(1), 73–86.
Boncio, P., Brozzetti, F. and Lavecchia, G., 1996, State of stress in the northern Umbria-Marche Apennines (central Italy): inferences from microearthquake and fault kinematics analyses, Annales Tectonicae 10(1-2), 80–97.
Boncio, P., Brozzetti, F., Ponziani, F., Barchi, M., Lavecchia, G. and Pialli, G., 1998, Seismicity and extensional tectonics in the northern Umbria-Marche Apennines, Mem. Soc. Geol. It. 52, 539–555.
Brozzetti, F., 1995, Stile strutturale della tettonica distensiva nell'Umbria occidentale: l'esempio dei Massicci Mesozoici Perugini, Studi Geologici Camerti vol. spec. 1995(1), 105–119.
Brozzetti, F. and Lavecchia, G., 1994, Seismicity and related extensional stress field: the case of the Norcia Seismic Zone (Central Italy), Annales Tectonicae 8(1), 36–57.
Calamita, F. and Pizzi, A., 1994, Recent and active extensional tectonics in the southern Umbro-Marchean Apennines (Central Italy), Mem. Soc. Geol. It. 48, 541–548.
Calamita, F., Coltorti, M., Pierantoni, P.P., Pizzi, A., Scisciani, V. and Turco, E., 1999, Relazioni tra le faglie quaternarie e la sismicità nella dorsale Appenninica umbro-marchigiana: L'area di Colfiorito. Studi Geologici Camerti 14 (1996- 97), 177–191.
Cattaneo, M., Augliera, P., Gorini, A., Govoni, A., Marcucci, S., Michelini, A., Monachesi, G., Romanelli, M., Spallarossa, D., Trojani, L. and XGUMS, this volume, The 1997 Umbria-Marche (Italy) earthquake sequence: analysis of the data recorded by the local and temporary networks.
Cello, G., Deiana, G., Mangano, P., Mazzoli, S., Tondi, E., Ferreli, L., Maschio, L., Michetti, A.M., Serva, L. and Vittori, E., 1998, Evidence for surface faulting during the September 26, 1997, Colfiorito (Central Italy) earthquakes, Journal of Earthquake Engineering 2(2), 303–324.
Cello, G., Mazzoli, S., Tondi, E. and Turco, E., 1997, Active tectonics in the central Apennines and possible implications for seismic hazard analysis in peninsular Italy, Tectonophysics 272, 43–68.
Cinti, F., Cucci, F., Marra, F. and Montone, P., 1998, Preliminary Analysis of the Surface Effects Produced by the Umbria-Marche Seismic Sequence and Possible Seismotectonic Implications, European Geophysical Society - Annual Conference, Nice, France, 1998, abstract.
C.P.T.I., 1999, Catalogo Parametrico dei Terremoti Italiani, ING, GNDT, SGA, SSN (eds). Editrice Compositori, Bologna (Italy), 88 pp.
Decandia, F.A., Lazzarotto, A., Liotta, D., Cernobori, L. and Nicolich, R., 1998, The CROP 03 traverse: insights on postcollisional evolution of the Northern Apennines, Mem. Soc. Geol. It. 52, 427–439.
Deschamps, A., Iannaccone, G. and Scarpa, R., 1984, The Umbrian earthquake (Italy) of 19 September 1979, Annales Geophysicae 2(1), 29–36.
Deschamps, A., Scarpa, R. and Selvaggi, G., 1989, Analisi sismologica del settore settentrionale dell'Appennino umbromarchigiano, Atti GNGTS 8th Conference 1, 9–15.
Ekstrom, G., Morelli, A., Boschi, E. and Dziewonski, A.M., 1998, Moment tensor analysis of the central Italy earthquake sequence of September-October 1997, Geoph. Res. Lett. 25(11), 1971–1974.
Federico, C. and Pauselli, C., 1998, Thermal evolution of the Northern Apennines (Italy), Mem. Soc. Geol. It. 52, 267–274.
Frepoli, A., Amato, A., Mariucci, M.T. and Montone, P., 1998, Active stress along the crop 03 section, Mem. Soc. Geol. It. 52, 259–266.
Galli, P., Bosi, V., Galadini, F., Meghraoui, M., Messina, P., Basili, R., Moro, M. and Sposato, A., 1998, Fratturazione superficiale connessa ai terremoti umbro-marchigaini del settembre-ottobre 1997, Il Quaternario 10(2), 255–262.
Gregori, L., 1990, Geomorfologia e neotettonica dell'area di Colfiorito, Geog. Fis. e Din. Quat. 13(1), 43–52.
Haessler, H., Gaulon, R., Rivera, L., Console, R., Frogneux, M., Gasparini, G., Martel, L., Patau, G., Siciliano, M. and Cisternas, A., 1988, The Perugia (Italy) earthquake of 29, April 1984: a microearthquake survey. Bull. Seism. Soc. Am. 78(6), 1948–1964.
Lavecchia, G., Brozzetti, F., Barchi, M., Keller, J. and Menichetti, M., 1994, Seismotectonic zoning in east-central Italy deduced from the analysis of the Neogene to present deformations and related stress fields, Soc. Geol. Am. Bull. 106, 1107–1120.
Lavecchia, G. and Pialli, G., 1980, Appunti per uno schema strutturale dell'Appennino umbro-marchigiano. 3 - La copertura, Studi Geologici Camerti 6, 23–30.
Mongelli, F. and Zito, G., 1991, Flusso di calore nella regione Toscana, Studi Geologici Camerti vol. spec. 1991/1, pp. 91–98.
Ofoegbu, G.I. and Ferrill, D.A., 1998, Mechanical analyses of listric normal faulting with emphasis on seismicity assessment, Tectonophysics 284, 65–77.
Pasquale, V., Verdoya, M., Chiozzi, P. and Augliera, P., 1993, Dependence of the seismotectonic regime on the thermal state in the northern Italian Apennines, Tectonophysics 217, 31–41.
Perno, U., 1969, Note illustrative del Foglio 123 őAssisiŕ. Serv. Geol. It., Rome, 76 pp.
Sibson, R.H., 1982, Fault zone models, heat flow, and the depth distribution of earthquakes in the continental crust of the United States. Seism. Soc. Am. Bull. 72, 151–163.
Sibson, R.H., 1983, Continental fault structure and shallow earthquake source. J. Geol. Soc. London 140, 741–767.
Stramondo, S., Tesauro, M., Briole, P., Sansosti, E., Salvi, S., Lanari, R., Anzidei, M., Baldi, P., Fornaro, G., Avallone, A., Buongiorno, M.F., Franceschetti, G. and Boschi, E., 1999, The September 26, 1997 Colfiorito, Italy, earthquakes: modeled coseismic surface displacement from SAR interferometry and GPS. Geophys. Res. Lett. 26(7), 883–886.
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Boncio, P., Lavecchia, G. A geological model for the Colfiorito earthquakes (September-October 1997, central Italy). Journal of Seismology 4, 345–356 (2000). https://doi.org/10.1023/A:1026509717771
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DOI: https://doi.org/10.1023/A:1026509717771