Abstract
Using template matching and GPS data, we investigate the evolution of
seismicity and observable deformation in Central Apennines. Seismicity
appears more persistent at the base of the seismogenic layer than in the
shallower crust. Diffuse activity is reported on segments at depth,
alternating along strike with apparent quiescence on segments that
experienced one or more Mw6+ earthquakes in 1997, 2009 and 2016. Central
Apennines are likely underlain by a sizeable shear zone with areas of
diffuse seismicity bounding shallow normal faults where Mw6+ earthquakes
occurred. The deformation observed at the surface seems to follow the
seismicity variations at the base of seismogenic layer along the
Apenninic chain. Principal and independent component analysis of GPS
data exhibits a transient when the 2016 foreshock sequence starts. This
transient propagated northward from the Campotosto fault up to the Alto
Tiberina fault system and has likely loaded the Mw6+ 2016 earthquake
sequence.