Stress triggering and field observations of the 2016 central Italy earthquake sequence

Three M≥6 earthquakes struck central Italy between August and October in 2016. The earthquake sequence ruptured the Mt Vettore and Laga faults and culminated in a M6.6 event that re-ruptured parts of the Mt Vettore fault that broke in the first two events. We present initial field observations made in the aftermath of each event including structural measurements of fault offsets in addition to photogrammetry and terrestrial laser scans of the fault ruptures that document the co-seismic and immediate post-seismic evolution of the surface ruptures. Surface observations showed visible ruptures on the Mt Vettore fault for all three events with different surface rupture lengths and surface offsets recorded in each event
We use slip inversion models derived from InSAR and seismology observations to calculate the stress changes caused by each event on both the Laga and Mt Vettore faults and also the surrounding faults in the central Apennines. We show the changes in Coulomb stress on the Mt Vettore fault caused by the fault two events prior to the M=6.6 event on 30th October.