A set of seismic reflection surveys were conducted in May 2019 in the Ossola Valley, Western Italian Alps, to image the geologic structure below two proposed boreholes. The boreholes plan to penetrate the upper 2 km of the lower continental crust, a zone of much scientific interest. The seismic surveys have defined the valley structure to depths of 550 m, determined the dip of geological banding, and ruled out the possibility of major geologic drilling hazards that could be encountered.

We examine the spatial variability of the crustal thickness beneath the broader European Alpine region by using teleseismic earthquake information (receiver functions) on a large amount of seismic waveform data. We compile a new Moho depth map of the broader European Alps and make our results freely available. We anticipate that our results can potentially provide helpful hints for interdisciplinary imaging and numerical modeling studies. 

We present high-resolution tomography images of upper mantle structure beneath the E Alps and the adjacent Bohemian Massif. The northward-dipping lithosphere, imaged down to ∼200 km beneath the E Alps without signs of delamination, is probably formed by a mixture of a fragment of detached European plate and the Adriatic plate subductions. A detached high-velocity anomaly, sub-parallel to and distinct from the E Alps heterogeneity, is imaged at ∼100–200 km beneath the southern part of the BM.

The gravity field of the Earth expresses the overall effect of the distribution of different rocks at depth with their distinguishing densities. Our work is the first to present the high-resolution gravity map of the entire Alpine orogen, for which high-quality land and sea data were reprocessed with the exact same calculation procedures. The results reflect the local and regional structure of the Alpine lithosphere in great detail. The database is hereby openly shared to serve further research.

This paper presents a high-resolution 3-D shear wave velocity (v_S) model of the Bohemian Massif crust imaged from high-density data and enhanced depth sensitivity of tomographic inversion. The dominant features of the model are relatively higher v_S in the upper crust than in its surrounding, a distinct intra-crustal interface, and a velocity decrease in the lower part of the crust. The low v_S in the lower part of the crust is explained by the anisotropic fabric of the lower crust.