[S-TT39] Synthetic Aperture Radar and its application

[STT39-P09] Development of portable SAR for detection of volcano deformation: application of SAR interferometry to the repeat observation data

*Taku Ozawa¹, Yuji Himematsu¹, Akira Nohmi², Masanori Miyawaki² (1.National Research Institute for Earth Science and Disaster Resilience, 2.Alouette Technology Inc.)

Keywords:SAR, SCOPE, volcano, crustal deformation

Synthetic aperture radar (SAR) transmits radar waves from the ground and can detect crustal deformation with high spatial and temporal resolution. To obtain crustal deformation data useful for evaluating volcanic activity, we are developing a portable SAR that can conduct repeated observations without being fixed to the site, under the Project B of the Integrated Program for Next Generation Volcano Research and Human Resource Development. We named this SAR sensor “SAR for Crustal defOrmation with Portable Equipment (SCOPE).” SCOPE detects crustal deformation over a wide area by repeating mobile observations at several points, thus differing from the general ground-based SAR (GB-SAR). SCOPE has four observation types: GB-SAR, car-borne SAR, cart-borne SAR, man-borne SAR, which are used to conduct such mobile observations efficiently. This study carried out repeat observations with a 1-day interval using GB-SAR and car-borne SAR, and obtained a high coherence and reasonable phase distribution. When using the man-borne SAR type, moderate coherence was obtained. However, the SAR image was not focused sufficiently, and an inappropriate phase slope in the interferogram appeared, suggesting that improvements in the observation method and SAR processing were necessary. We also investigated the temporal persistence of coherence in the application of SAR interferometry to SCOPE data. Sufficient coherence was obtained to detect crustal deformation in the sparsely vegetated areas for a data pair at 1 year interval. Even in densely vegetated areas, sufficient coherence was obtained from a data pair at intervals of several months. These results show that SCOPE has a high potential for crustal deformation detection by the repeated observations.