From depth to surface of the 2016-2017 Central Italy earthquake sequence: integrating subsurface geology, seismicity and satellite observations

The 2016-2017 Central Italy earthquake sequence offers a unique opportunity to investigate the complex interplay between deep crustal structures, seismic activity, and surface deformation. A decade after the event, we attempt to synthesize all the available multidisciplinary observations describing the evolution of the mainshocks: the Mw 6.0 Amatrice earthquake in August 2016, the Mw 6.5 Norcia and Mw 5.9 Visso earthquakes in October 2016 and the Mw 5.5 Campotosto earthquake in January 2017. This cascade of shocks activated an 80-km long system of SW-dipping normal faults, breaking the entire upper crust from 12 km depth to the surface.

We integrate multidisciplinary datasets to observe the fault system from different perspectives, spanning from deep crustal processes (seismicity) and tectonic architecture (subsurface geology) to surface expressions (outcropping geology and surface ruptures), and satellite-based observations (SAR-based techniques). The data are jointly used to investigate the structural framework, fault kinematics and deformation pattern along the fault system.

High-detailed DInSAR-based deformation maps of the three largest earthquakes are reconstructed to characterize both surface ruptures associated with major fault segments and off-fault deformation. The geometry of the main seismogenic faults at depth are reconstructed using seismicity distribution and cross-section balancing, while at surface we retrieve geological constraints including coseismic ruptures. The analysis highlights distinct rupture behaviors of individual fault segments and their specific contributions to the observed ground deformation.

Post-seismic deformation is instead investigated analyzing SBAS-DInSAR time series, together with the spatial distribution of seismicity that occurred following the sequence onset, until 2025. The results show how the hanging wall of the active fault system underwent sustained subsidence during this period, characterized by spatially variable rates.

By bridging insights from the deep subsurface to satellite-based remote sensing, this study provides a comprehensive understanding of the processes driving the 2016-2017 Central Italy earthquakes and its temporal evolution in the last decade.