Geoinformatics Unit

Paper accepted for publication in Remote Sensing

February 5, 2020

Our paper entitled "A Semiautomatic Pixel-Object Method for Detecting Landslides Using Multitemporal ALOS-2 Intensity Images" led by Bruno Adriano has been accepted for publication in Remote Sensing.

The rapid and accurate mapping of large-scale landslides and other mass movement disasters is crucial for prompt disaster response efforts and immediate recovery planning. As such, remote sensing information, especially from synthetic aperture radar (SAR) sensors, has significant advantages over cloud-covered optical imagery and conventional field survey campaigns. In this work, we introduced an integrated pixel-object image analysis framework for landslide recognition using SAR data. The robustness of our proposed methodology was demonstrated by mapping two different source-induced landslide events, namely, the debris flows following the torrential rainfall that fell over Hiroshima, Japan, in early July 2018 and the coseismic landslide that followed the 2018 Mw6.7 Hokkaido earthquake. For both events, only a pair of SAR images acquired before and after each disaster by the Advanced Land Observing Satellite-2 (ALOS-2) was used. Additional information, such as digital elevation model (DEM) and land cover information, was employed only to constrain the damage detected in the affected areas. We verified the accuracy of our method by comparing it with the available reference data. The detection results showed an acceptable correlation with the reference data in terms of the locations of damage. Numerical evaluations indicated that our methodology could detect landslides with an accuracy exceeding 80%. In addition, the kappa coefficients for the Hiroshima and Hokkaido events were 0.30 and 0.47, respectively.

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(a) Locations of the target areas where the studied events occurred. (b,c) show the target regions (black dashed rectangles) encompassing the Hokkaido and Hiroshima regions, respectively. (d) Hokkaido study area. The red star shows the location of the epicenter. The blue rectangle shows the footprint covered by Advanced Land Observing Satellite-2 (ALOS-2). (e) Hiroshima study area. The blue rectangles show the footprints covered by ALOS-2.