Polarimetric decomposition analysis of ALOS PALSAR observation data before and after a landslide event

Chinatsu Yonezawa, Manabu Watanabe, Genya Saito

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60 Citations (Scopus)


Radar scattering mechanisms over landslide areas were studied using representative full polarimetric parameters: Freeman-VDurden decomposition, and eigenvalue-Veigenvector decomposition. Full polarimetric ALOS (Advanced Land Observation Satellite) PALSAR (Phased Array type L-band Synthetic Aperture Radar) datasets were used to examine landslides caused by the 2008 Iwate-Miyagi Nairiku Earthquake in northern Japan. The Freeman-VDurden decomposition indicates that areas affected by large-scale landslides show dominance of the surface scattering component in both ascending and descending orbit data. The polarimetric parameters of eigenvalue-Veigenvector decomposition, such as entropy, anisotropy, and alpha angle, were also computed over the landslide areas. Unsupervised classification based on the H-α plane explicitly distinguishes landslide areas from others such as forest, water, and snow-covered areas, but does not perform well for farmland. A landslide area is difficult to recognize from a single-polarization image, whereas it is clearly extracted on the full polarimetric data obtained after the earthquake. From these results, we conclude that 30-m resolution full polarimetric data are more useful than 10-m resolution single-polarization PALSAR data in classifying land coverage, and are better suited to detect landslide areas. Additional information, such as pre-landslide imagery, is needed to distinguish landslide areas from farmland or bare soil.

Original languageEnglish
Pages (from-to)2314-2328
Number of pages15
JournalRemote Sensing
Issue number8
Publication statusPublished - 2012 Aug


  • Earthquake
  • Landslide
  • Polarimetric SAR
  • Scattering component disaster monitoring


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