Estimation of three-dimensional crustal movements in the 2011 Tohoku-Oki, Japan, earthquake from TerraSAR-X intensity images

• Published in: Natural hazards and earth system sciences Vol. 15; no. 3; pp. 637 - 645
• Main Authors: Liu, W, Yamazaki, F, Matsuoka, M, Nonaka, T, Sasagawa, T
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 27.03.2015; Copernicus Publications
• Subjects: Accuracy; Analysis; Coasts; Crust (Geology); Crustal movement; Displacement; Earthquakes; Ground stations; Radar; Radar imaging; SAR (radar); Seismic activity; Synthetic aperture radar; Three dimensional models; Tsunamis; Japan
• ISSN: 1684-9981; 1561-8633; 1684-9981
• DOI: 10.5194/nhess-15-637-2015

The Tohoku-Oki earthquake on 11 March 2011 caused significant widespread crustal movements. In a previous study, we proposed a method for capturing two-dimensional (2-D) surface displacements from a pair of pre- and post-event TerraSAR-X (TSX) intensity images. However, it is impossible to detect three-dimensional (3-D) displacements from one pair of TSX images. In this study, three pairs of pre- and post-event TSX images taken on different paths were used to estimate 3-D crustal movements. The relationship between the actual 3-D displacements and the converted 2-D movements in the synthetic-aperture radar (SAR) images was derived based on the observation model of a SAR sensor. The 3-D movements were then calculated from three sets of detected 2-D movements that occurred within a short time period. Compared with GPS observations, the proposed method was found to be capable of detecting the 3-D crustal movements with sub-pixel accuracy.