Landslide-Induced Damage Probability Estimation Coupling InSAR and Field Survey Data by Fragility Curves

Matteo Del Soldato,Riccardo Fanti,Federico Raspini,Nicola Casagli,Francesco Poggi,Lorenzo Solari,Roberto Tomás

doi:10.3390/rs11121486

Abstract

Landslides are considered to be one of the main natural geohazards causing relevant economic damages and social effects worldwide. Italy is one of the countries worldwide most affected by landslides; in the Region of Tuscany alone, more than 100,000 phenomena are known and mapped. The possibility to recognize, investigate, and monitor these phenomena play a key role to avoid further occurrences and consequences. The number of applications of Advanced Differential Interferometric Synthetic Aperture Radar (A-DInSAR) analysis for landslides monitoring and mapping greatly increased in the last decades thanks to the technological advances and the development of advanced processing algorithms. In this work, landslide-induced damage on structures recognized and classified by field survey and velocity of displacement re-projected along the steepest slope were combined in order to extract fragility curves for the hamlets of Patigno and Coloretta, in the Zeri municipality (Tuscany, northern Italy). Images using ERS1/2, ENVISAT, COSMO-SkyMed (CSK) and Sentinel-1 SAR (Synthetic Aperture Radar) were employed to investigate an approximate 25 years of deformation affecting both hamlets. Three field surveys were conducted for recognizing, identifying, and classifying the landslide-induced damage on structures and infrastructures. At the end, the damage probability maps were designed by means of the use of the fragility curves between Sentinel-1 velocities and recorded levels of damage. The results were conceived to be useful for the local authorities and civil protection authorities to improve the land managing and, more generally, for planning mitigation strategies.

Highlights

Landslides are considered to be one of the main natural geohazards causing relevant economic damages and indirect social effects worldwide
The period December 2003–June 2010 covered by ENVISAT data shows a slightly different situation (Figure 5b) in the northern portion of the hamlet, where velocity along the slope (Vslope) velocities are always lower than −10 mm/year
Sentinel-1 data, spanning between March 2015 and June 2018, confirm the Vslope distribution of the other interferometric products, with velocities increasing from NW to SE, with Vslope passing from −15 mm/year in the northern portion of the hamlet, to −53 mm/year in the landslide toe area (Figure 5d)

Summary

Introduction

Landslides are considered to be one of the main natural geohazards causing relevant economic damages and indirect social effects worldwide. Landslides can be triggered by natural (e.g., intense rainfalls) or anthropogenic (e.g., deforestation or poor urban planning) factors [2,3,4,5,6]. In both cases, they can impact structures and infrastructures causing considerable socio-economic damages, direct (e.g., maintenance or reconstruction of damaged structures) and indirect (e.g., difficulties to evaluate, losses of services) [1,7,8,9,10,11,12], as well as fatalities. Unlike ground-based monitoring systems, Earth-observation techniques allow measuring land motion of wide areas with millimetre to centimetre accuracy with a much higher frequency of acquisition and decreasing costs (with respect to reach similar precision with conventional techniques) [40]

Methods

Results

Conclusion