The effectiveness of high-resolution LiDAR data combined with PSInSAR data in landslide study

Andrea Ciampalini,William Frodella,Federico Raspini,Federica Bardi,Silvia Bianchini,Sandro Moretti

doi:10.1007/s10346-015-0663-5

Andrea Ciampalini, William Frodella + Show 4 more

Open Access

https://doi.org/10.1007/s10346-015-0663-5

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Journal: Landslides	Publication Date: Dec 5, 2015
Citations: 64	License type: CC BY 4.0

Affiliation: University of Florence

Abstract

The spatial resolution of digital elevation models (DEMs) is an important factor for reliable landslide studies. Multi-interferometric techniques such as persistent scatterer interferometric synthetic aperture radar (PSInSAR) are used to evaluate the landslide state of activity and its ground deformation velocity, which is commonly measured along the satellite line of sight (LOS). In order to compare velocities measured by different satellites in different periods, their values can be projected along the steepest slope direction, which is the most probable direction of real movement. In order to achieve this result, DEM-derived products are needed. In this paper, the effectiveness of different DEM resolutions was evaluated in order to project ground deformation velocities measured by means of PSInSAR technique in two different case studies in the Messina Province (Sicily, southern Italy): San Fratello and Giampilieri. Three DEMs were used: (i) a 20-m resolution DEM of the Italian Military Geographic Institute (IGM), (ii) a 2-m resolution DEM derived from airborne laser scanning (ALS) light detection and ranging (LiDAR) data for the San Fratello 2010 landslide, and (iii) a 1-m resolution DEM derived from ALS LiDAR data for the area of Giampilieri. The evaluation of the applied method effectiveness was performed by comparing the DEMs elevation with those of each single permanent scatterer (PS) and projecting the measured velocities along the steepest slope direction. Results highlight that the higher DEM resolution is more suitable for this type of analysis; in particular, the PS located nearby the watershed divides is affected by geometrical problems when their velocities are projected along the steepest slope.

Highlights

Spaceborne synthetic aperture radar (SAR) images are currently used to detect, monitor, and forecast active geological processes leading to ground deformation
The directions of the projected permanent scatterer (PS) velocity, by using both digital elevation models (DEMs), are in agreement with the average slope direction, except for the area characterized by a higher terrain roughness, where the 2-m resolution DEM resulted more accurate. This agreement strongly decreases in correspondence with the divide, especially in the previously mentioned area where the aspect derived from the 20-m resolution DEM shows a different orientation with respect to the real morphology
The comparison among the PS heights and the elevations measured with the available DEM show a good correlation for both the 20-m and the 1-m resolution DEMs,but, in this case, the DEM having the higher resolution shows a better R2=0.9992, whereas R2 for Conclusion In this work, the reliability of high spatial resolution DEMs was tested in order to provide new opportunities and challenges for mapping landslide morphology with high accuracy, both through visual interpretation and statistical analysis

Summary

Introduction

Spaceborne synthetic aperture radar (SAR) images are currently used to detect, monitor, and forecast active geological processes leading to ground deformation. In order to compare different sensors data, characterized by different look angles and wavelengths, and different LOS, Notti et al (2014) suggested to project the velocity, measured along the LOS, along the steepest slope (Eq 1).

Results

Conclusion