The analyzes on the satellite data made it possible to measure the movements of the ground generated by the 4 seismic events of magnitude from 5 to 5.5 which occurred on 18 January in the Montereale area, and to identify the source fault of the earthquakes. This activity is coordinated by the Civil Protection Department (DPC) and is carried out by a team of researchers from the National Institute of Geophysics and Volcanology (INGV) and the Institute for Electromagnetic Sensing of the Environment National Research Council (CNR-IREA of Naples), centers of expertise in the sectors of seismology and satellite radar data processing, with the support of the Italian Space Agency (ASI). Thanks to the use of radar data, acquired by the satellites of the Sentinel-1 constellation of the Copernicus European Program and ALOS-2 of the Japanese Space Agency (JAXA) under an agreement with ASI, the CNR-IREA research team was able able to measure the ground movements caused by the earthquakes of 18 January. INGV used the ground displacement maps elaborated by IREA-CNR to generate a model of the fault along which the 8 events of 10 January occurred within a few hours, at depths varying between 4 and 18 km. The maximum sliding of the earth's crust along the fault amounts to about 90 cm and did not reach the surface but stopped at a depth of about 3 km (Figure 1). The reconstructed model is still preliminary but clearly indicates that these earthquakes occurred on the regional fault plane of Monte Gorzano, the same one on which the sequence with the Amatrice event began on 24 August 2016, and on which they occurred in 2009 of the smaller events in the Campotosto area (Figures 2 and 3).
Figure 1 - South-west view of the Monte Gorzano fault with the segments activated from 2009 to 18 January 2017.
Figure 2 - Plan view of the fault segments that have been activated since 2009 with seismic events of different magnitudes. The source of the Montereale earthquakes is indicated.
Figure 3 - Perspective view from the west of the source patterns of the main earthquakes in the area from 6 April 2009 to today. See Figure 3 for geographical references.
