Analysis of urban areas affected by the 2011 off the Pacific coast of Tohoku earthquake and tsunami with L-Band SAR full-polarimetric mode

Manabu Watanabe, Takeshi Motohka, Yousuke Miyagi, Chinatsu Yonezawa, Masanobu Shimada

Research output: Contribution to journalArticlepeer-review

50 Citations (Scopus)

Abstract

The 2011 off the Pacific coast of Tohoku earthquake was observed using phased array type L-band synthetic aperture radar (PALSAR) and polarimetric and interferometric airborne synthetic aperture radar (PiSAR) full-polarimetric data. Representative polarimetric parameters were calculated from full-polarimetric data for urban areas, where most of the buildings were destroyed by the subsequent tsunami, in order to identify the radar scattering mechanism in these areas. These parameters were compared with the ones observed before the disaster. The full-polarimetric data analysis shows that the affected areas were represented by surface scattering with high entropy, indicating that a complex scattering mechanism with nonreflection symmetry is involved. The coherence between HH and VV and that between RR and LL are the most important factors in distinguishing the disaster areas from the data. Alpha angle and anisotropy are also important factors in this respect; however, anisotropy derived from PiSAR data does not show the difference between areas with collapsed and still-standing buildings. This may be because the azimuth slope angle for the target urban area is different before and after the disaster for both PALSAR and PiSAR data. Owing to the double-bounce scattering from azimuthally rotated targets in the urban areas, the power estimated from the four-component decomposition model is distributed within a wide range not only for double-bounce scattering but also for volume and surface scatterings. Additionally, the model does not show a systematic change between before and after the disaster, and σ 0 for four polarizations with 30-m resolution does not show a systematic difference.

Original languageEnglish
Article number6145738
Pages (from-to)472-476
Number of pages5
JournalIEEE Geoscience and Remote Sensing Letters
Volume9
Issue number3
DOIs
Publication statusPublished - 2012

Keywords

  • Coherence
  • decomposition
  • earthquake
  • tsunami

ASJC Scopus subject areas

  • Geotechnical Engineering and Engineering Geology
  • Electrical and Electronic Engineering

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