Long-Term Displacement Monitoring of Slow Earthflows by Inclinometers and GPS, and Wide Area Surveillance by COSMO-SkyMed Data

Abstract

With reference to two slow earthflows in structurally complex clayey formations of the Italian southern Apennines, this paper shows the results of a long-term displacement monitoring using integrated systems of inclinometers and GPS, and their comparison with PSInSAR data. A fixed-in-place and traversal inclinometer system, first installed in 2004, recorded both the shear displacements along the slip bands, and the internal deformations of the landslide masses. A GPS network of permanent stations and benchmarks, installed in 2006–2007 in 23 strategic points of the slope, allowed for the temporal continuity of displacement monitoring. The two long series of data allowed to evaluate the factor scaling of the PSInSAR COSMO-SkyMed data, although the component of the displacement vector along the line of sight (LOS) was small. PSInSAR data allowed for the monitoring extension to houses and rigid structures that acted as reflectors. The joint data analysis allowed for the comprehension of the main features of the landslides’ kinematics.

Long-Term Monitoring of a Tunnel in a Landslide Prone Area by Brillouin-Based Distributed Optical Fiber Sensors

“…The fault has probably been the cause of the first slope failure and subsequent landslide evolution. The landslide is characterized by an average inclination of about 10 • , approximately 1250 m in length, 150 to 300 m in width, and multiple slip surfaces [29]. In the accumulation zone, a local slide occurs in correspondence to a bend of the Basento river.…”

“…Fixed GPS stations with continuous acquisition and benchmarks for periodic measurements were installed in 2006 and have provided displacement data since then. Details about installation, data acquisition, and displacement time series registered from 2006 to 2020 are reported in [29]. SAR COSMO-SkyMed (CSK) satellite images of years 2011-2014 were also processed and interpreted [29].…”

“…Details about installation, data acquisition, and displacement time series registered from 2006 to 2020 are reported in [29]. SAR COSMO-SkyMed (CSK) satellite images of years 2011-2014 were also processed and interpreted [29].…”

“…Details about installation, data acquisition, and displacement time series registered from 2006 to 2020 are reported in [29]. SAR COSMO-SkyMed (CSK) satellite images of years 2011-2014 were also processed and interpreted [29]. CSK satellite SAR data relative to the period 2011-2014 were processed by differential interferometry techniques within the PST-A (in Italian: Piano Straordinario di Telerilevamento Ambientale), i.e., the high precision plan of remote sensing of the Italian Ministry of Environment [30].…”

Hydraulic Conductivity and Pore Water Pressures in a Clayey Landslide: Experimental Data

“…The landslide body, with an average inclination of about 10 • , is approximately 1250 m long, from 100 to 600 m wide; the maximum slip surface depth provided by the inclinometers is about 40 m (Figure 3) and the soil volume is about 3 × 10 6 m 3 . The landslide movements have been monitored by inclinometers since 2004, by GPS since 2006 [23], and recently by Cosmo SkyMed [24]. The interpretation of the experimental data ( Figures 3 and 4) suggests that: 1) sliding localized along a thin slip zone is the current prevailing type of movement, while internal shear strains are important in the shallow soil cover; 2) the displacement rate can be considered uniform in the cross sections of the landslide body; 3) the average yearly rates of deep displacements AB ( Figure 3) can be considered constant over the monitoring time; 4) such average yearly rates decrease in the downslope direction.…”