Subsidence Detected by Multi-Pass Differential SAR Interferometry in the Cassino Plain (Central Italy): Joint Effect of Geological and Anthropogenic Factors?

In the present work, the Differential SAR Interferometry (DInSAR) technique has
been applied to study the surface movements affecting the sedimentary basin of Cassino
municipality. Two datasets of SAR images, provided by ERS 1-2 and Envisat missions, have
been acquired from 1992 to 2010. Such datasets have been processed independently each other
and with different techniques nevertheless providing compatible results. DInSAR data show a
subsidence rate mostly located in the northeast side of the city, with a subsidence rate
decreasing from about 5–6 mm/yr in the period 1992–2000 to about 1–2 mm/yr between 2004
and 2010, highlighting a progressive reduction of the phenomenon. Based on interferometric
results and geological/geotechnical observations, the explanation of the detected movements
allows to confirm the anthropogenic (surface effect due to building construction) and
geological causes (thickness and characteristics of the compressible stratum)