ASSESSING LEVELLING AND DINSAR FOR DEFORMATION MONITORING IN SEISMIC REGION

Abstract

Carrying out monitoring surveys in seismic regions is good practice both for the assessment of land deformation and the evaluation of building structures standing on it. In this work, topographic levelling and DInSAR techniques have been used for displacement measurement. These geomatic techniques are rarely applied in the same context and attempts are made to combine the results obtained for having a complete analysis of the site. The proposed work analyses, compares and discusses topographic levelling and advanced multi-temporal DInSAR techniques used to detect and measure ground deformation when the occurrence of seismic events might have played a role in the displacement. The area of interest had already been under observation through ground-based monitoring surveys, by means of metal bolts attached to façades of buildings detected by topographic level, from 1998 to 2021. The DInSAR analysis was carried out exploiting Sentinel-1A/B data acquired during the period 2014–2021. The goal of the DInSAR processing stage of the procedure is to derive the deformation map of the area of interest from SAR data. A zero date has been set for both survey methods in order to define similar time series for comparison analysis. The results showed that ground displacements measured by levelling and DInSAR have similar trends. On the geomorphological aspect, the same distribution map of terrain subsidence is found in both techniques.