Assessing Urban Landslide Dynamics through Multi-Temporal InSAR Techniques and Slope Numerical Modeling

Nicușor Necula,Simone Fiaschi,Mihai Niculiță,Paolo Riccardi,Rinaldo Genevois,Mario Floris

doi:10.3390/rs13193862

Abstract

Landslides threaten more than before the urbanized areas and are a worldwide growing problem for the already affected communities and the local authorities committed to landslide risk management and mitigation. For this reason, it is essential to analyze landslide dynamics and environmental conditioning factors. Various techniques and instruments exist for landslide investigation and monitoring. Out of these, Multi-temporal Synthetic Aperture Radar Interferometry (MT-InSAR) techniques have been widely used in the last decades. Their capabilities are enhanced by the availability of the active Sentinel-1 mission, whose 6-day revisiting time enables near real-time monitoring of landslides. Interferometric results, coupled with ground measurements or other approaches such as numerical modeling, significantly improve the knowledge of the investigated surface processes. In this work, we processed the C-band SAR images of the available European Space Agency (ESA) satellite missions, using MT-InSAR methods to identify the surface deformations related to landslides affecting the Iași Municipality (Eastern Romania). The results (i.e., velocity maps) point out the most active landslides with velocities of up to 20 mm/year measured along the satellite Line of Sight (LOS). Following, we focused on the most problematic landslide that affects the Țicău neighborhood and is well-known for its significant implications that it had. To better understand its behavior and the sensitivity of the displacements to the environmental factors (i.e., rainfall), we carried out 2D numerical modeling using a finite difference code. The simulated displacement field is consistent with the InSAR displacements and reveals the most active sectors of the landslide and insights about its mechanism.

Highlights

The human impact, through topographic and hydrologic modifications, is a triggering and preparatory factor for landslides
The application of Multi-temporal SAR Interferometry techniques (MT-InSAR) and numerical modeling of slope failures in urban areas is a must in the current context of urban territorial expansion to successfully identify and monitor possible slope deformations that might threaten the infrastructure and people
For the case of Ias, i Municipality, the benefits of coupling MT-InSAR results and slope numerical simulations allowed us: (1) to identify the potentially dangerous areas affected by slope instabilities; (2) to properly delimitate the extent of the active sector tampering the T, icău neighborhood’s integrity; (3) to monitor the landslide activity and its behavior related to the rainfall amount and water level changes; (4) to argue the landslide typology based on its velocity and failure mechanism

Summary

Introduction

The human impact, through topographic and hydrologic modifications, is a triggering and preparatory factor for landslides. As landslides evolve, they will control human activities, and a feedback loop will occur. Landslides limit and interfere with the infrastructure development, utility networks or may obstruct the expansion of urbanized areas. In the worst-case scenario, they destroy and inflict damages to buildings, infrastructure, and city heritage [1] and generate substantial economic losses [2,3,4,5,6,7]. Tools, and instruments are developing to detect, monitor, and analyze landslide processes. The Multi-temporal Interferometric Synthetic Aperture Radar (MTInSAR) techniques are one of them, and more and more, they are used to investigate

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Discussion

Conclusion