Shallow Fault Detection Using Seismic Reflection Methods: A Case Study from Moriago della Battaglia, Veneto, Italy

Shallow fault detection is critical for seismic-hazard assessment along the active front of the Venetian Southern Alps. This thesis presents a high-resolution 2-D reflection survey acquired on the Piave alluvial plain near Moriago della Battaglia (Montello foreland, NE Italy) and develops a reproducible processing workflow tailored to noisy, near-surface conditions. Four partially overlapping ~300-m profiles were recorded with dense receiver coverage and a portable hammer source. To stabilise near-surface velocities and guide early processing decisions, first arrivals were picked in Geogiga Frontend Express and inverted in Geogiga DW Tomo (10 iterations; final RMS misfit ≈ 7.9 ms), providing a shallow velocity model used to justify a water-table time cut and to inform reflection statics. Reflection processing in Shearwater Reveal comprised geometry assignment and CMP sorting, attenuation of surface waves by f–k filtering and low-cut, first-arrival muting, velocity analysis (semblance), NMO correction, and stacking. Despite persistent ground roll and cultural noise, the final stacked section is interpretable between ~200 and 600 ms TWT, where several subhorizontal reflectors are resolved together with two zones of disrupted continuity (near CMP ~120 and ~230) that are consistent with shallow deformation. Outside this window, imaging deteriorates due to reduced fold, low signal-to-noise ratio, and rapid amplitude decay from the low-energy source. The results show that even in challenging urban-proximal settings, integrating refraction tomography with a disciplined reflection workflow yields actionable constraints on shallow structure. Methodological lessons include: maximise near-surface fold and bandwidth; shorten pre-trigger to preserve record length; apply targeted ground-roll suppression early; and confine interpretation to intervals where acquisition and velocity control support the λ/4 resolution limit. Future work should increase source energy and channel count, acquire complementary surface-wave data for Vs control, and replicate profiles along the Montello front to test lateral continuity of the candidate fault zones.