Moho and LAB below the Western Alps from P and S Receiver Function analysis and joint inversion
- 1Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy (caterina.montuori@ingv.it)
- 2Institute of Physics of the Earth, Moscow, Russia
- 3A full list of authors appears at the end of the abstract
We used the data from the dense, broadband AlpArray Seismic Network to derive a set of Receiver Function (RF) measurements on the Moho and Lithosphere-Asthenosphere Boundary (LAB) for a broad region encompassing the Western Alps and including the Ivrea Geophysical Body (IGB), a fragment of mantle emplaced in the lower continental crust. Our analysis fills an information gap since, in spite of numerous active and passive seismological investigations on the Alpine orogen, many of the observations focus on the Moho or the deeper part of the mantle, while reliable information on the LAB below the Alps is scarce. Moreover, our findings provide an additional contribution to resolving the debated topic of the existence of continuous or interrupted continental subduction below the Western Alps.
We derive seismic velocity profiles of the crust-uppermost mantle below each of the 50 analyzed stations down to about 250 km depth, through the joint inversion of P and S RFs. We constrain the lateral variations of the Moho and LAB topographies across the colliding plates, and quantify the errors related to our measurements. Our observations allow us to considerably expand the published data of the Moho depth and to add a unique set of new measurements of the LAB (Monna et al., 2022).
Our results yield a comparable thickness (on average 90–100 km) of the Eurasia and Adria lithospheres, which are colliding below the IGB; Eurasia is not presently subducting below Adria with vertical continuity. These findings suggest that there is a gap between the superficial (continental) European lithosphere and the deep (oceanic) lithosphere, confirming the discontinuous structure imaged by some seismic tomography models.
the AlpArray Working Group: list on http://www.alparray.ethz.ch/home/
Monna, S., Montuori, C., Frugoni, F., Piromallo, C., Vinnik, L., & AlpArray Working Group (2022). Moho and LAB across the Western Alps (Europe) from P and S receiver function analysis. Journal of Geophysical Research: Solid Earth, 127, e2022JB025141. https://doi.org/10.1029/2022JB025141
How to cite: Montuori, C., Monna, S., Frugoni, F., Piromallo, C., Vinnik, L., and Working Group, A.: Moho and LAB below the Western Alps from P and S Receiver Function analysis and joint inversion, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12370, https://doi.org/10.5194/egusphere-egu23-12370, 2023.
