The 1976 Friuli (NE Italy) thrust faulting earthquake: A reappraisal 23 years later

Abstract

We revisit the 1976 Friuli earthquake sequence by combining hypocenters relocation, long period surface wave inversion, field geology and strong motion modelling. We show that fault-related folding is the main active deformation by which the seismic energy was released during the main shock (Ms=6.5) and that some of the surface effects reported in 1976 correspond to widespread bedding planes displacements induced by flexural-slip folding. The fault evolved from blind to semi-blind along strike showing the control of the inherited structural geology on the fault surface break and rupture arrest. Our fault model produces waveforms that fit the accelerograms recorded in the area.