Project Details
Projekt
Seismic Attenuation and Texture of the Eastern Margin of the Adriatic Plate (A-MAP)
Subject Area
Geophysics
Term
since 2025
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 560280130
A-MAP exploits the information of the high-frequency scattered seismic wave field to derive new information on dynamics and structure of the crust and upper mantle along the eastern margin of the Adriatic plate. We develop 1-D, 2-D and 3-D models of subsurface heterogeneity and frequency-dependent seismic P- and S-wave attenuation. To this end, we simulate the seismic energy propagation from the first arrival to the late coda using energy transfer theory. This allows us to distinguish between intrinsic absorption and scattering attenuation to gain new perspectives on subsurface processes and structures. We apply geophysical imaging to the entire Adriatic region covered by AdriaArray as well as to the key areas of the Dinarides-Hellenides transition and the Kefalonia Transform Fault System. 1-D depth-dependent attenuation models are developed, which are required for correct modeling of the amplitudes in seismic wave propagation. Based on the derived attenuation models, we investigate earthquake source spectra to determine moment magnitudes, corner frequencies and stress drops to improve the source characterization of small events compared to empirical magnitudes. This will provide the basis for physics based ground motion modeling for seismic hazard analysis in the second phase of DEFORM. 2D and 3D attenuation models derived from earthquake data and environmental noise provide new information about the structure of the subsurface that is not contained in seismic velocity models. Seismic absorption is an indicator of temperature and fluid content. Seismic texture or heterogeneity, quantified by scattering attenuation, is an indicator of the density of cracks and faults and of small-scale changes in mineralogical composition. We use seismic scattering tomography as a geophysical imaging technique that provides evidence of heat flow and plate deformation, particularly vertical mixing and uplift of heterogeneous lower crustal material. Our methods, based on seismic scattering theory and high-frequency wavefield information, thus provide a high-resolution spatial representation of the viscosity of the crust, and with lower accuracy that of the mantle lithosphere and asthenosphere. In combination with other geoscientific methods used in DEFORM, we determine the intrinsic frequency dependence of viscoelastic behavior over time scales from seismic wave propagation to lithospheric deformation. In this way, we are making an important contribution to the understanding of the dynamic processes of the eastern Adriatic.
DFG Programme
Priority Programmes
