JDR Vol.17 No.5 pp. 609-619
doi: 10.20965/jdr.2022.p0609


Development of Portable SAR for Detection of Volcano Deformation: Application of SAR Interferometry to the Repeated Observation Data

Taku Ozawa*,†, Yuji Himematsu*, Akira Nohmi**, and Masanori Miyawaki**

*National Research Institute for Earth Science and Disaster Resilience (NIED)
3-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan

Corresponding author

**Alouette Technology Inc., Mitaka, Japan

February 1, 2022
June 6, 2022
August 1, 2022
volcano deformation, SCOPE, GB-SAR, car-borne, man-borne

Synthetic aperture radar (SAR), which transmits radar waves from the ground, 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 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 observations at several points, which differs from the general ground-based SAR (GB-SAR). SCOPE has four observation types: GB-SAR, car-borne SAR, cart-borne SAR, and man-borne SAR, which are used to conduct such mobile observations efficiently. This study performed repeated observations with a 1-day interval using GB-SAR and car-borne SAR and obtained high coherence and reasonable phase distribution. When using the man-borne SAR type, moderate coherence was obtained. However, focusing on the SAR image was insufficient, and an inappropriate phase slope appeared in the interferogram, suggesting that improvements in the observation and analysis methods remained. We also investigated the temporal persistence of coherence when applying SAR interferometry to the SCOPE data. Sufficient coherence was obtained to detect crustal deformation in sparsely vegetated areas for a data pair at a 1-year interval. Even in densely vegetated areas, sufficient coherence was obtained from the data pair at intervals of several months. These results show that SCOPE has high potential for detecting crustal deformation based on repeated observations.

Cite this article as:
T. Ozawa, Y. Himematsu, A. Nohmi, and M. Miyawaki, “Development of Portable SAR for Detection of Volcano Deformation: Application of SAR Interferometry to the Repeated Observation Data,” J. Disaster Res., Vol.17, No.5, pp. 609-619, 2022.
Data files:
  1. [1] Y. Miyagi, T. Ozawa, T. Kozono, and M. Shimada, “Long-term lava extrusion after the 2011 Shinmoe-dake eruption detected by DInSAR observations,” Geophys. Res. Lett., Vol.41, No.16, pp. 5855-5860, doi: 10.1002/2014GL060829, 2014.
  2. [2] F. Amelung, S. Jónsson, H. Zebker, and P. Segall, “Widespread uplift and ‘trapdoor’ faulting on Galápagos volcanoes observed with radar interferometry,” Nature, Vol.407, No.6807, pp. 993-996, doi: 10.1038/35039604, 2000.
  3. [3] H. Ueda, E. Fujita, M. Ukawa, E. Yamamoto, M. Irwan, and F. Kimata, “Magma intrusion and discharge process at the initial stage of the 2000 activity of Miyakejima, Central Japan, inferred from tilt and GPS data,” Geophs. J. Int., Vol.161, No.3, pp. 891-906, 2005.
  4. [4] D. Tarchi, N. Casagli, S. Moretti, D. Leva, and A. J. Sieber, “Monitoring landslide displacements by using ground-based synthetic aperture radar interferometry: Application to the Ruinon landslide in the Italian Alps,” J. Geophys. Res. Solid Earth, Vol.108, Issue B8, Article No.2387, doi: 10.1029/2002JB002204, 2003.
  5. [5] F. D. Traglia, M. Battaglia, T. Nolesini, D. Lagomarsino, and N. Casagli, “Shifts in the eruptive styles at Stromboli in 2010–2014 revealed by ground-based InSAR data,” Scientific Reports, Vol.5, Article No.13569, doi: 10.1038/srep13569, 2015.
  6. [6] T. Ozawa, Y. Aoki, S. Okuyama, X. Wang, Y. Miyagi, and A. Nohmi, “Database of crustal deformation observed by SAR: Improving atmospheric delay mitigation for satellite SAR interferometry and developing L-band multi-type portable SAR,” J. Disaster Res., Vol.14, No.5, pp. 713-727, doi: 10.20965/jdr.2019.p0713, 2019.
  7. [7] T. Ozawa and H. Nohmi, “Effect of vegetation on surface deformation measurement using InSAR investigated from laboratory experiments,” J. Geod. Soc. Japan, Vol.64, pp. 81-88, doi: 10.11366/sokuchi.64.81, 2019 (in Japanese with English abstract).
  8. [8] D. E. Barrick, “FM/CW radar signals and digital processing,” National Oceanic and Atmospheric Administration Technical Report, 283-WPL 26, Accession No.AD0774829, 1973.
  9. [9] L. M. H. Ulander, H. Hellsten, and G. Stenstrom, “Synthetic-aperture radar processing using fast factorized back-projection,” IEEE Trans. Aerospace Elect. Sys., Vol.39, No.3, pp. 760-776, 2003.
  10. [10] Y. Himematsu and T. Ozawa, “Intermittent uplift on Azuma volcano detected by PALSAR-2 and Sentinel-1 data,” Abst. Fall Meeting Volcanol. Soc. Japan, p. 11, 2021 (in Japanese).
  11. [11] S. Narita, T. Ozawa, Y. Aoki, M. Shimada, M. Furuya, Y. Takada, and M. Murakami, “Precursory ground deformation of the 2018 phreatic eruption on Iwo-Yama volcano, revealed by four-dimensional joint analysis of airborne and spaceborne InSAR,” Earth, Planets and Space, Vol.72, Article No.145, doi: 10.1186/s40623-020-01280-5, 2020.
  12. [12] T. Ozawa and S. Shimizu, “Atmospheric noise reduction in InSAR analysis using numerical weather model,” J. Geod. Soc. Japan, Vol.56, No.4, pp. 137-147, 2010 (in Japanese with English abstract).
  13. [13] P. Wessel and W. H. F. Smith, “New, improved version of Generic Mapping Tools released,” EoS Trans. AGU, Vol.79, Issue 47, p. 579, 1998.

*This site is desgined based on HTML5 and CSS3 for modern browsers, e.g. Chrome, Firefox, Safari, Edge, Opera.

Last updated on Aug. 05, 2022