The processing carried out by CNR-IREA on the radar images acquired by the Japanese sensor ALOS 2 (operating in L band), relating to the earthquake of 30 October 2016, confirms the results obtained from the previous analyzes based on data from the Sentinel-1 and COSMO-SkyMed sensors , adding new details.
In particular, the co-seismic deformation map (fig. 1), calculated using the pre-event and post-event ALOS 2 images (acquired respectively on August 24 and November 2, 2016), highlights two main deformation lobes. The first, which affects the Norcia area, shows a westerly shift and uplift which, in the radar line of sight, correspond to about 35 cm of deformation. The second highlights a significant subsidence of the ground in the Castelluccio area (more than 60 cm in line of sight of the sensor) and an eastward shift of the Montegallo area.
Figure 1 Co-seismic deformation map (in the radar line of sight), obtained with the differential radar interferometry technique, starting from the ALOS 2 radar data acquired on 24/08/2016 and 02/11/2016, from ascending orbits
High definition image downloadable at the following link
A highlighting animation is also available the temporal evolution of the surface deformations detected by the Japanese satellite ALOS 2 following the seismic events of 24 August 2016 and 26/30 October 2016, and can be downloaded at following link
The ALOS 2 interferogram elaborated by the National Institute of Geophysics and Volcanology - INGV (fig. 2) once again shows the complexity of deformation at a local scale. The two profiles (fig. 3) traced through the zones of maximum deformation in the areas affected by the two earthquakes of Visso M 5.9 and Norcia M 6.5, show the movement of the earth's surface caused by the sliding in depth of the two sides of the fault plane, which occurred during the two seismic events. Thanks to their lower sensitivity to vegetation cover compared to data from other satellites, ALOS 2 data provide very important information for reconstructing the geometry and position of seismic sources.
Figure 2 ALOS 2 interferogram. The ellipse shows where the terrain has moved away from the satellite along the line of sight. This direction is inclined to the vertical by 34° to the west.
The lines that cut the interferogram from west to east are the outline traces in figure 3.
Figure 3 Ground movement values caused by the two events in Visso and Norcia, measured on two profiles whose traces are shown in fig. 2.
The data obtained from the ALOS 2 satellite are the result of existing agreements between the Italian and Japanese Space Agency (JAXA). The data obtained from the ALOS 2 satellite are the result of existing agreements between the Italian and Japanese Space Agency (JAXA), a further demonstration of the international cooperation which is the basis of space activity, as already highlighted with the Cosmo SkyMed and Sentinel satellites in multiple occasions.