Railways' stability observed in Campania (Italy) by InSAR data

Campania region is characterized by intense urbanization, active volcanoes, subsidence, and landslides; therefore, the stability of public transportation structures is highly concerned. We have applied DInSAR technique to a stack of 25 X-band radar images of Cosmo-SkyMed (CSK) satellites collected over an area in Campania, in order to monitor the railways' stability. The study area was already investigated with older, low-resolution sensors like ERS1/2 and ENVISAT-ASAR before, but the number of obtained persistent scatterers (PSs) was too limited to get useful results. Here, for the first time we apply CSK high resolution imagery to this study area, so obtaining a number of PSs sufficient to detect possible deformations on the railways. We focused on a bridge at Triflisco, over the Volturno River. Our results demonstrate a stable condition. Comparison with the local thermal data shows that the main deformation on the bridge is limited to periodical deformation of the steel structure.