Abstract
Layering in the upper and lower mantle across the Mediterranean has been determined using P-to-S converted phases identified through receiver function analysis. Conversion of the receiver function's time axis to depth was based on local 1D S-velocity models. The 1D velocity model for each station was extracted from a three-dimensional S-velocity model for the Mediterranean region (EAV03), enhanced with crustal structure derived from receiver function analysis. Under the Mediterranean region we observed a mantle transition zone thickness of 261 ± 10 km, on average, which agrees with a dominance of high velocities imaged in tomographic models at these depths. A thick mantle transition zone (> 270km) was observed in regions with ongoing or past subduction: eastern Spain, southern Italy, southern Greece and the north-western African coast. Conversions from the 410 km and 660km discontinuities were clearly observed for most stations. Amplitudes of both discontinuities are anomalously large throughout the Mediterranean region, 4.9% and 5.7%, respectively. We observed significant conversions from the 520km discontinuity. The lower mantle showed strong lateral variations resulting in spatially incoherent converted phases from discontinuities near 860km, between 900km and 1200km, and 1320km depth.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 233-250 |
| Number of pages | 18 |
| Journal | Physics of the Earth and Planetary Interiors |
| Volume | 148 |
| Issue number | 2-4 |
| DOIs | |
| State | Published - Feb 2005 |
Funding
Funding for this study was provided by the Swiss National Science Foundation (SNF). Financial support for MIDSEA came from the SNF, with additional support from the Carnegie Institution of Washington, the French National Scientific Research Center and the University of Nice at Sophia-Antipolis, the Italian National Institute of Geophysics and Volcanology, and numerous local organizations (see Van der Lee et al. (2001) ). We thank the many individuals associated with MIDSEA (see Van der Lee et al. (2001) ); their support has been invaluable. Data for PAB (GSN), MAHO (Geofon), and VSL, KEG and MDT (all MedNet) were obtained from the ORFEUS Data Center, the GEOFON Data Center, and the IRIS DMC, respectively. We greatly appreciate regular and valuable discussions with F. Marone and C. Schmid. We are very grateful to M. Flanagan, G. Helffrich, and H. Paulssen, for insightful comments on this study and thorough, constructive reviews, which helped to significantly improve the manuscript.
Keywords
- Discontinuities
- Lower mantle
- Mediterranean
- Receiver functions
- Transition zone
- Upper mantle
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Geophysics
- Physics and Astronomy (miscellaneous)
- Space and Planetary Science
