Landslide Monitoring and Deformation Interpretation base on InSAR and Geological Analysis

Abstract:

Landslides are widespread in the mountainous areas of western China and their formation conditions are often highly concealed and complex, which greatly increases the difficulty of early identification and monitoring of regional landslide hazards. The spaceborne InSAR technique is a powerful tool to detect the surface deformation and has obvious advantages in the identification and monitoring of potentially unstable slopes at a catchment scale.

However, in areas with significant topographic relief, the phase error caused by the vertical stratification of the atmospheric and the residual phase of the undulating terrain can not be ignored, Besides, decorrelations caused by complex terrain and vegetation coverage in southwest mountainous areas of China, make it impossible for conventional time series InSAR methods to identify sufficient measurement points to get desired monitoring results.

In this paper, we are intended to deeply analyze the temporal and spatial distribution of the information, such as amplitude, phase and coherence of SAR images to improve the error-signal model of InSAR time series analysis; besides, we will make a joint exploitation of persistent scatterers (PS) and distributed scatterers (DS) to depict the landslide surface displacement in detail to improve the InSAR ability in mapping landslide deformation feature by combining multi-source and multi-orbit SAR dataset.

In our study, archived L-band ALOS PALSAR and C-band Sentinel IW datasets will be analyzed to detect the potentially unstable slopes. Case study of Danba County using both ALOS PALSAR images (2006–2011) and Sentinel IW images (2017-2018) have demonstrated the effectiveness of our propose method in monitoring the activity of potential landslide in China's mountainous west.

Later, a joint analysis of the existing terrestrial observations, the InSAR measurements, and the field surveys will be conducted to give validation and geological interpretation of the InSAR derived results. In order to explore the relations between the InSAR deformation results and the internal failure mechanism, the deformation evolution characteristic, the triggering factors, and the deformation failure modes of typical landslide will be analyzed and discussed.