The lithosphere and asthenosphere system in Italy as inferred from the Vp and Vs 3D velocity model and Moho map

Abstract

We present an updated high-resolution tomographic P- and S-wave velocity model of the lithosphere and asthenosphere system in Italy, obtained by adding the observations from ∼25,000 earthquakes (recorded between 2003 and April 2012 at three-component stations) to the previously inverted dataset (165,000 P-wave phases from ∼8000 events recorded between 1988 and 2002 at single-component). The final dataset includes ∼586,000 P- and ∼290,000 S-wave arrival times. The main strength of this research is the use of a method able to model P- and S-seismic phases refracted at the Moho discontinuity. We use a new and original map of the 3D Moho geometry obtained by integrating selected high quality controlled source seismology (CSS) and teleseismic receiver function data. Resolution strongly benefits also from the fast increase in number and quality of INGV National Seismic Network since year 2003 and from its integration with several permanent regional seismic networks. This study confirms the main structural features in the best-resolved parts of the inverted volume and much better images details in the less resolved areas of previous Vp models, due to both the larger number of inverted phases and the more even distribution of seismic stations. A new 3D Vp/Vs model is presented and discussed. Shallow structures and the relationships between the Adriatic, Tyrrhenian, and Adria plates are better imaged.