Seismic survey of sub-vertical structures, Val Sesia

In preparation for the deepest drilling target of the DIVE project, the first results of the seismic reflection site survey across the Insubric Line and at the Balmuccia peridotite body have recently been published in Tectonophysics. They show that the near vertical structures seen at the surface can be continued downwards for about 1 kilometer without major disruption, which is both a methodological achievment and good news for further site investigations.

Earthquakes and Hinduism?

Yes, these two words are somehow connected. Hindiusm’s rich literature include several stories where earthquakes and related phenomena are described. And exactly these can be very useful to communicate about earthquakes to people with religious backround and religious perception of our environment. Our most recent work lead by Shiba Subedi explores this topic, which you can read in full length and in a shorter summary, including illustrations.

Summer fieldwork

Despite the varying weather conditions our group could undertake fieldwork in the area shown on the photo below. We plan to launch an open modelling challenge by sharing the new data and inviting anyone to submit models explaining the data. More details to come after data preprocessing.

Joint inversion results on the Ivrea body along Val Sesia

Our new seismic and gravity data enabled a high-resolution passive geophysical imaging study, and constrained the structure and physical properties of the Ivrea Geophysical Body along the Val Sesia profile. The structure fits well the local and regional geology, the densities and velocities fit well the rock’s properties in situ. What else? The shallowest portion of the discontinuity appears to be relatively sharp (ca. 400-600 m transition thickness). For details, see our recent Frontiers in Earth Sciences paper, lead by Matteo Scarponi. What’s next? Active geophysical results… (some patience, please).

Upscaling metamorphic rates

The overall rate at which rocks transform to other rocks under high pressure and temperature (metamorphism) is classically constrained from analysing samples that fit in one’s hand, or even smaller scales (for example powder). Our most recent paper presents a coupled geophysical-petrological model constrained by field data, showing that the apparent rate of transformation in the lower crust beneath the Himalayas fits very well the small-scale estimates. This is the first estimate over long time‐ and large spatial scales, demonstrating that regional metamorphic rates can be realistically upscaled for geodynamic modelling. Full details in this open access paper – the graphical abstract is here below.