Integration of Satellite Interferometric Data in Civil Protection Strategies for Landslide Studies at a Regional Scale

Silvia Bianchini,Patrick Thuegaz,Davide Bertolo,Lorenzo Solari,Filippo Catani

doi:10.3390/rs13101881

Abstract

Multi-Temporal Satellite Interferometry (MTInSAR) is gradually evolving from being a tool developed by the scientific community exclusively for research purposes to a real operational technique that can meet the needs of different users involved in geohazard mitigation. This work aims at showing the innovative operational use of satellite radar interferometric products in Civil Protection Authority (CPA) practices for monitoring slow-moving landslides. We present the example of the successful ongoing monitoring system in the Valle D’Aosta Region (VAR-Northern Italy). This system exploits well-combined MTInSAR products and ground-based instruments for landslide management and mitigation strategies over the whole regional territory. Due to the critical intrinsic constraints of MTInSAR data, a robust regional satellite monitoring integrated into CPA practices requires the support of both in situ measurements and remotely sensed systems to guarantee the completeness and reliability of information. The monitoring network comprises three levels of analysis: Knowledge monitoring, Control monitoring, and Emergency monitoring. At the first monitoring level, MTInSAR data are used for the preliminary evaluation of the deformation scenario at a regional scale. At the second monitoring level, MTInSAR products support the prompt detection of trend variations of radar benchmarks displacements with bi-weekly temporal frequency to identify active critical situations where follow-up studies must be carried out. In the third monitoring level, MTInSAR data integrated with ground-based data are exploited to confirm active slow-moving deformations detected by on-site instruments. At this level, MTInSAR data are also used to carry out back analysis that cannot be performed by any other tool. From the example of the Valle D’Aosta Region integrated monitoring network, which is one of the few examples of this kind around Europe, it is evident that MTInSAR provides a great opportunity to improve monitoring capabilities within CPA activities.

Highlights

Geohazard management and mitigation practices involve the correct choice of the monitoring system, the selection of the geohazards to be prioritized, and the development of a real-time or nearreal-time monitoring service with ad hoc alerts based on thresholds
MTInSAR is nowadays a technique validated by a high number of successful applications, and in many cases, it has been testified as accurate as other sources of ground displacement measurements (e.g., GNSS)
From the Civil Protection Authority (CPA) perspective, this screening activity has the advantage of providing regularly updated estimates of terrain deformation at relatively low cost on large areas where in situ data cannot be acquired for different reasons, which implies a reduction in human efforts in terms of ground surveys and can allow the a priori detection of the most moving areas where to allocate additional resources

Summary

Introduction

Since the last decade of the twentieth century, the use of satellite remote sensing techniques for geohazard prevention, mapping, and monitoring has grown significantly, contributing to landslide risk reduction, impact assessments, and disaster responses in urban areas. It is crucial to have a tool enabling the CPA to investigate the largest possible extension of the territory and to detect new deformation phenomena or accelerations of the existing ones as early as possible. This screening capability provides the CPA with the opportunity to perform a fullscale regional assessment of the landslide phenomena, with a proper allocation of human and financial resources. From an operational point of view, MTInSAR allows the investigation of uninhabited areas (in the case of VAR, the high mountainous environment) in any climatic condition, with an appreciable and positive impact on the safety of the personnel

Objectives

Discussion

Conclusion