Combining Sentinel-1 Interferometry and Ground-Based Geomatics Techniques for Monitoring Buildings Affected by Mass Movements

Abstract

Mass movements represent a serious threat to the stability of human structures and infrastructures, and cause loss of lives and severe damages to human properties every year worldwide. Built structures located on potentially unstable slopes are susceptible to deformations due to the displacement of the ground that at worst can lead to total destruction. Synthetic aperture radar (SAR) data acquired by Sentinel-1 satellites and processed by multi-temporal interferometric SAR (MT-InSAR) techniques can measure centimeter to millimeter-level displacement with weekly to monthly updates, characterizing long-term large-scale behavior of the buildings and slopes. However, the spatial resolution and short wavelength weaken the performance of Sentinel-1 in recognizing features (i.e., single buildings) inside image pixels and maintaining the coherence in mountainous vegetated areas. We have proposed and applied a methodology that combines Sentinel-1 interferometry with ground-based geomatics techniques, i.e., global navigation satellite system (GNSS), terrestrial laser scanning (TLS) and terrestrial structure from motion photogrammetry (SfM), for fully assessing building deformations on a slope located in the north-eastern Italian pre-Alps. GNSS allows verifying the ground deformation estimated by MT-InSAR and provides a reference system for the TLS and SfM measurements, while TLS and SfM allow the behavior of buildings located in the investigated slope to be monitored in great detail. The obtained results show that damaged buildings are located in the most unstable sectors of the slope, but there is no direct relationship between the rate of ground deformation of these sectors and the temporal evolution of damages to a single building, indicating that mass movements cause the displacement of blocks of buildings and each of them reacts differently according to its structural properties. This work shows the capability of MT-InSAR, GNSS, TLS and SfM in monitoring both buildings and geological processes that affect their stability, which plays a key role in geohazard analysis and assessment.

Automation of Pan-Sharpening Methods for Pléiades Images Using GIS Basic Functions

“…In addition, the timeframes can be vastly reduced by resorting to the automation of the operations properly programmed in sequence, according to a logic flowchart. To demonstrate this, the following 14 The main characteristics of those methods are reported below, including formulas in view of implementing them by means of GIS tools. However, those formulas are firstly inserted in our proposed GIS-based procedure for Pléiades images, then applied manually to the same dataset to verify their correct in an automatic way.…”

“…If close-range geomatics techniques are useful for the survey and investigation of civil engineering constructions, such as buildings, bridges and water towers [1], satellite remote sensing is traditionally suitable to support studies on geographic areas, e.g., urban growth effects [2,3], glacier inventory [4,5], desertification [6,7], grassland monitoring [8,9], burned area detection [10,11], seismic damage assessment [12,13], land deformations monitoring aims-landslides [14], land subsidence [15], coastal changes [16], etc. However, a detailed investigation of the Earth's surface and land cover can be performed using Very High Resolution (VHR) satellite images, characterised by pixel dimension of panchromatic (PAN) data equal or less than 1 m. Generally, VHR sensors carried on a satellite can capture also multispectral (MS) images that have a lower resolution than PAN [17,18].…”

Editorial for Special Issue “Monitoring Land Subsidence Using Remote Sensing”

“…The monitoring of ground movements made great progress in the last decades with the development of Global Positioning System (GPS)-Global Navigation Satellite System (GNSS) [10] and Interferometric Synthetic Aperture Radar (InSAR) [11] technologies together with the use of different approaches, from analytical to 3D numerical, for the analysis of the involved physical processes [9]. Starting from the 2000s, further advances in the satellite-borne and in-situ technologies made the monitoring of Earth surface motions an easier and more common geodetic task [12].…”

“…The PSI and SBAS approaches can be successfully applied over many different ground targets such as buildings, infrastructures, outcrops, base soils, low-vegetated area, etc. [11], and in several research fields, such as tectonics and volcanology [15], landslides [10,11,16], clay deposits deformations [5,17], and groundwater/oil/natural gas depletion [9,18].…”

“…Despite the large advantages of the multi-temporal DInSAR methodology, the acquisition of ground-based data, mainly from leveling and GNSS techniques, is crucial for validation and integration of the satellite measurements. Nowadays, the land subsidence monitoring mostly relies on the integration between available and reliable InSAR data and sparse, but highly accurate, GNSS measurements, which are often compared to other geodetic observation methods [9][10][11][12]15,19,20].…”