1. Quantifying rates of active extension and seismic hazard in the upper plate of subduction zones
- Author
-
Meschis, Marco
- Subjects
- 551.22
- Abstract
To test the hypothesis that crustal deformation within the deforming upper plate of the Ionion Subduction Zone, influences uplift in the Calabrian Arc (CA), sequences of tectonically-deformed uplifted palaeoshorelines have been mapped, dated and assigned ages. These regions have historically experienced damaging earthquakes, yet, crustal deformation rates spanning the Late Quaternary are unclear and poorly-constrained. Uplifted Quaternary palaeoshorelines are preserved: (i) on the hangingwalls and footwalls of major Quaternary normal faults deforming the CA and (ii) within the deforming foreland region. This thesis constrains the relationship between historical seismicity, "regional" uplift and upper plate crustal deformation, quantifying both the "local" signal due to the normal faulting and the "regional" uplift. To assign ages to palaeoshorelines, a synchronous correlation approach is applied, driven by new absolute age controls alongside those available in the literature. This assigns ages to un-dated palaeoshorelines suggesting: (i) new uplift rate scenarios and (ii) new long-term fault slip-rates. Uplift rate variations are mapped: (i) along the strike of the upper plate normal faults and (ii) along the foreland region, either constant and fluctuating through time. The deformation rates are used to discuss seismic hazard in southern Italy. Moreover, elastic half-space modelling is used to replicate levelling data from 1907-1909 to test if the Messina Strait fault is the seismogenic source of the 1908 Mw 7.1 Messina Earthquake, the most destructive earthquake recorded in Europe. Overall, this thesis shows that: (i) critically-assigning ages to un-dated palaeoshorelines by applying synchronous correlation approach is crucial to obtain reliable long-term deformation rates and (ii) upper plate crustal vertical rates should be removed if observations from deforming upper plates are used to derive slip distribution on the subduction interface.
- Published
- 2019