Ultrashallow seismic imaging of the causative fault of the 1980, M6.9, southern Italy earthquake by pre‐stack depth migration of dense wide‐aperture data

摘要: [1] A two-step imaging procedure, including pre-stack depth migration (PSDM) and non-linear multiscale refraction tomography, was applied to dense wide-aperture data with the aim of causative fault 1980, M6.9, Irpinia normal faulting earthquake in a very complex geologic environment. PSDM is often ineffective for ultrashallow (100 m less) laterally heterogeneous media because difficulty estimating correct velocity model migration. Dense profiling allowed us build accurate models across zone by tomography record wide-angle reflections from steep reflectors. provided better respect conventional post-stack migration, improved definition geometry apparent cumulative displacement. Results indicate that this strategy can be effective near-surface detection characterization. Fault location are agreement paleoseismic two nearby trenches. The estimated vertical throw only 29–38 m. This value, combined slip rate determined trench data, suggests young age (97–127 kyr) inception.