Publication Date:
2024-04-30
Description:
We investigate the seismic structure of the mantle wedge of the Apennines subduction zone (Central Mediterranean)
using teleseismic receiver function (RF). We inverted RF for both isotropic and anisotropic properties of
the mantle wedge, from below the overriding Moho to the “plate boundary”, i.e. the interface that separate the
slab from the mantle wedge. Given the distribution of the seismic network, we are able to map out the change in
the elastic properties at the transition between southern apennines and the Calabrian arc, given by the change in
the subduction style (i.e from the subduction of continental materials to oceanic plate). We found that the
anisotropy in the mantle wedge is similar between all seismic stations, generally highly anisotropic (〉 10%),
with a direction of the symmetry axis that rotates clockwise from North to South, following the Calabrian arc
geometry and likely indicating the mantle flow driven by the slab retreat. The elastic properties of the subducted
crust are more heterogeneous. To the North, the subducted crust shows a highly anisotropic (〉 10%) behavior,
and it occurs at larger depth (around 70 km depth), where to the South anisotropy is less intense (around 7%)
and the subducted crust is shallower (around 60 km depth). These results point out a change in the subduction
style that can be given by either a change in the metamorphic phase (more evolved blueschist facies stage to the
North, initial greenschist facies stage to the South) or a different origin for the subducted materials (continental
to the North and oceanic to the South). The differences in the anisotropic behavior of the subducted crust are
reflected in the topography of the plate boundary, which becomes shallower from North to South, suggesting the
existence of either a step in the slab topography or a more gentle ramp.
Description:
Published
Description:
102004
Description:
OST1 Alla ricerca dei Motori Geodinamici
Description:
JCR Journal
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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