Neo-deterministic seismic hazard assessment of Corsica-Sardinia block

Abstract

AbstractThe Corsica-Sardinia lithospheric block is commonly considered as a region of very low seismicity and the scarce reported seismicity for the area has till now precluded the reliable assessment of its seismic hazard. The time-honored assumption has been recently questioned and the historical seismicity of Sardinia has been reevaluated. Even more, several seismogenic nodes capable of M5 + have been recognized in the Corsica-Sardinia block exploiting the morphostructural zonation technique, calibrated to earlier results obtained for the Iberian peninsula, which has structural lithospheric affinities with the Corsica-Sardinia block. All this allows now for the computation of reliable earthquake hazard maps at bedrock conditions exploiting the power of Neo Deterministic Seismic Hazard Assessment (NDSHA) evaluation. NDSHA relies upon the fundamental physics of wave generation and propagation in complex geologic structures and generates realistic time series from which several earthquake ground motion parameters can be readily extracted. NDSHA exploits in an optimized way all the available knowledge about lithospheric mechanical parameters, seismic history, seismogenic zones and nodes. In accordance with continuum mechanics, the tensor nature of earthquake ground motion is preserved computing realistic signals using structural models obtained by tomographic inversion and earthquake source information readily available in literature. The way to this approach has been open by studies focused on continental Italy and Sicily, where the agreement between hazard maps obtained using seismogenic zones, informed by earthquake catalog data, and the maps obtained using only seismogenic nodes are very good.