Huge congratulations to SENSE student Max Lowe for publishing his first paper, from his Msc thesis, in EGU journal Solid Earth.
Max says –
This study estimates the gravitational contribution of former tectonic plates subducted into Earth’s interior (slabs) to the Alpine gravity field. Different seismological studies identified various slab segments beneath the Alpine mountain belt within Earth’s upper mantle. However, the position, geometry and extend of those slabs vary strongly in those studies. In addition, some recent gravity models do not account for such heterogeneities in the Earth’s mantle.
Here, the sensitivity of gravity measurements to variation in slab position, geometries and volume is tested. Therefore, two competing slab configurations are defined based on seismological findings. In addition, the gravity contribution caused by slab segments within the Earth’s mantle is estimated by forward calculating density distributions based on three different modelling approaches. a) direct conversion of seismic velocities to density distributions, b) density variation based on predefined slab configurations and c) calculating density distributions based on geophysical and petrological modelling taking rock composition, temperature and pressure into consideration.
We find that the gravity signal caused by the slab segments is sharp and can be separated for the different slab segments for the gravity field measured at near surface height. At satellite altitude the contribution of different slab segments cannot be separated anymore. We showed that slab segments can contribute up to 40 mGal to the Alpine gravity field. This is significant and demonstrates that future studies should account for densities variation within the mantle caused by slabs to provide a meaningful representation of the geodynamic complex Alpine area.
You can read the paper here.