Evidence of crustal thickening beneath the central Apennines (Italy) from teleseismic receiver functions Giuliana Mele a, ⁎ , Eric Sandvol b , Gian Paolo Cavinato c a Istituto Nazionale di Geofisica e Vulcanologia, Via di Vigna Murata, 605, 00143-Roma, Italy b Department of Geological Sciences, University of Missouri-Columbia, Columbia, MO 65201, USA c CNR-Istituto di Geologia Ambientale e Geoingegneria, Dipartimento di Scienze della Terra, Università di Roma “La Sapienza”, Piazzale Aldo Moro, 5,00185-Roma, Italy Received 17 October 2005; received in revised form 11 April 2006; accepted 18 May 2006 Available online 17 August 2006 Editor: S. King Abstract We computed receiver functions of teleseismic events that occurred within a distance of 35–90° and were recorded in central Italy by 15 temporary stations and 1 permanent station. In the receiver functions we identified the P-to-S phase converted at the Moho discontinuity beneath each station and estimated crustal thickness from the time delay of this phase with respect to the direct P arrival. For the temporary stations this relatively simple approach is justified given their limited recording period. To the permanent station we also applied the slant stacking technique to try to constrain the bulk crustal Vp/Vs and validate our estimate of crustal thickness. Our results show that, in central Italy, the Moho is shallow (∼ 22 km) beneath the Tyrrhenian margin of the peninsula and deepens toward the east. Beneath the central Apennines, Moho depth ranges from 39 to 47 km. The thickest crust matches the highest topography. At the Tremiti islands, in the Adriatic Sea, crustal thickness is 33 km. While our Moho depths beneath the Tyrrhenian side of the peninsula and the Adriatic Sea are in agreement with previous results, a new result of this study is the crustal thickening beneath the central Apennines. This leads to the conclusion that the central Apennine topography is supported by a significant crustal root. © 2006 Elsevier B.V. All rights reserved. Keywords: teleseismic receiver functions; crustal thickness; central Apennines; Italy 1. Introduction The Apennine mountain belt runs along the Italian peninsula, between the Tyrrhenian Sea to the west and the Adriatic Sea to the east. This chain formed since the early Miocene in response to the collision between the Adriatic and the European continental margins (e.g., [1–3]). In the late Miocene, the Tyrrhenian basin started to open west of the Apennines, and extension progressively migrated toward the east, as evidenced by volcanism and rifting along the western margin of the peninsula. The outer Apennine front also migrated eastward, overthrusting the Adriatic foreland (Fig. 1) (e.g., [4,5]). In central Italy the Apennines attain the highest elevation, with several mountains exceeding 2000 m and the highest peak of 2914 m in the Gran Sasso range Earth and Planetary Science Letters 249 (2006) 425 – 435 www.elsevier.com/locate/epsl ⁎ Corresponding author. Fax: +39 06 51860507. E-mail address: meleg@ingv.it (G. Mele). 0012-821X/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.epsl.2006.05.024