International Journal of Geosciences, 2015, 6, 938-961 Published Online August 2015 in SciRes. http://www.scirp.org/journal/ijg http://dx.doi.org/10.4236/ijg.2015.68075 Belt-Parallel Shortening in the Northern Apennines and Seismotectonic Implications Marcello Viti1, Enzo Mantovani1, Daniele Babbucci1, Caterina Tamburelli1, Nicola Cenni2, Massimo Baglione3, Vittorio D’Intinosante3 1Dipartimento di Scienze Fisiche, della Terra e dell’Ambiente, Università degli Studi di Siena, Siena, Italy 2Dipartimento di Fisica ed Astronomia, Università degli Studi di Bologna, Bologna, Italy 3Settore Sismica, Regione Toscana, Firenze, Italy Email:
[email protected] Received 15 June 2015; accepted 28 August 2015; published 31 August 2015 Copyright © 2015 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract Major seismic activity in the Northern Apennines concentrates in few zones, distributed in a pecu- liar way. It is argued that such context may be plausibly explained as an effect of belt-parallel shortening, which has caused oroclinal bending of the longitudinal ridges formed during the Late Miocene to Lower Pliocene evolutionary phase. The main effects of this process, developed since the upper Pliocene, have mainly affected the outer sectors of the belt. The major seismic sources have generated in the zones where different oroclinal bendings of adjacent ridges have produced extensional/transtensional deformation. In the inner side of the Northern Apennines, belt parallel shortening has occurred at a lower rate. The main effects have resulted from the shortening of the Albano-Chianti-Rapolano-Cetona ridge.