New Perspectives in Landslide Displacement Detection Using Sentinel-1 Datasets

Matteo Mantovani,Gianluca Marcato,Giacomo Tedesco,Giacomo Titti,Giulia Bossi,Luca Schenato,Alessandro Pasuto

doi:10.3390/rs11182135

Abstract

Space-borne radar interferometry is a fundamental tool to detect and measure a variety of ground surface deformations, either human induced or originated by natural processes. Latest development of radar remote sensing imaging techniques and the increasing number of space missions, specifically designed for interferometry analyses, led to the development of new and more effective approaches, commonly referred to as Advanced DInSAR (A-DInSAR) or Time Series Radar Interferometry (TS-InSAR). Nevertheless, even if these methods were proved to be suitable for the study of a large majority of ground surface dynamic phenomena, their application to landslides detection is still problematic. One of the main limiting factors is related to the rate of displacement of the unstable slopes: landslides evolving too fast decorrelate the radar signal making the interferometric phase useless. This is the reason why A-DInSAR techniques have been successfully applied exclusively to measure very slow landslides (few centimetres per year). This study demonstrates how the C-band data collected since 2014 by the Sentinel-1 (S1) mission and properly designed interferometric approaches can pull down this restriction allowing to measure rate of displacements ten times higher than previously done, thus providing new perspectives in landslides detection. The analysis was carried out on a test site located in the Cortina d’Ampezzo valley (Eastern Italian Alps), which is affected by several earth flows characterized by different size and kinematics.

Highlights

The application of imaging radar remote sensing to geosciences is nowadays a fast moving field
This study demonstrates how the C-band data collected since 2014 by the Sentinel-1 (S1) mission and properly designed interferometric approaches can pull down this restriction allowing to measure rate of displacements ten times higher than previously done, providing new perspectives in landslides detection
The developments of radar remote sensing led to the study of ground surface dynamic phenomena and in 1993, Massonet [1] reported the first successful application of space-borne differential interferometic Synthetic Aperture Radar (SAR) (DInSAR) to map the co-seismic deformation of the Landers earthquake

Summary

Introduction

The application of imaging radar remote sensing to geosciences is nowadays a fast moving field. A-DInSAR offers the possibility to map and measure small ground displacements over large temporal and spatial scales with sub-centimetre accuracy, combining the high precision of classical geodetic surveys with the imaging property of remote sensing techniques These approaches have been successfully applied to monitor ground deformations of different origins, both natural and anthropic e.g., [1,6,7,8]. S1 satellites were designed to provide the scientific community with data continuity after the operational end of ERS and ENVISAT missions with enhanced temporal and spatial resolution, along with small orbital baselines These characteristics certainly favor the application of A-DInSAR analysis to landslides by loosening two major bonds such as the small dimensions and, occasionally, the high velocity of the mass movements. Mass movements different in size and rate of displacement by an order of magnitude have been discriminated, mapped and measured, establishing new boundaries for the application of radar remote sensing to landslides hazard assessment

Study Area

Interferometric Point Target Analysis

DInSAR Analysis

Discussion

Conclusions