Reflection seismic sections across the Geothermal Province of Tuscany from reprocessing CROP profiles

Abstract

We processed the seismic lines CROP-18 and the Tuscany segment of CROP-03, acquired in Southern Tuscany. The analyzed transects were originally designed to highlight deep crustal structures between the major reflector characterizing the geothermal fields (the K-horizon) and the Moho discontinuity. Our main target was to better depict the upper crustal structures, reprocessing the first 4–6s reflection times with the application of advanced techniques (wave equation datuming), improving signal/noise ratio and extracting information previously hidden by approximate static corrections and surface noise. We choose the wave equation datuming technique, a process of upward or downward continuation of the wave-field between two arbitrarily shaped surfaces. The wave equation datuming was applied to move shots and receivers to a given datum plane, removing time shifts related to topography and to near-surface velocity variations. The datuming procedure largely contributed to attenuate ground roll, enhance higher frequencies, increase resolution and improve the signal/noise ratio.The time migrated output sections show new evidence of regional continuity of high amplitude horizons, a better fitting with the surface geological setting and with well data resembling the local industry investigations. The interpretation confirms the fluids role, the contribution to the crustal reflectivity mostly by thermo-metamorphic processes and defines the tectonic setting.