2:45 PM - 3:00 PM
[STT40-05] Development of a portable radar interferometer for volcano observation (SCOPE): Experimental observations at Mt. Fuji and Sakurajima
Keywords:SAR, SCOPE, Sakurajima, Fuji
In the Next Generation Volcano Research Project Theme B Sub-Theme 2, we are developing a radar interferometer named SCOPE to investigate crustal deformation by transmitting radar waves from the ground. In particular, SCOPE has been designed to enable mobile observation in various locations by selecting a suitable observation method for the conditions of the observation site, such as a rail-based, a car-borne, a cart-borne, and a man-borne methods. Conducting SCOPE observations in the Azuma-yama, the Tokachi-dake, and the Unzen volcanoes, we succeeded to detect volcano deformation and the lava dome deformation. As the effectiveness of SCOPE has been confirmed, we will utilize SCOPE as one of the tools for mobile observation for volcano activity evaluation in the future. In order to utilize SCOPE for such mobile observations, experimental observations were conducted to demonstrate the feasibility of long-distance observations and to investigate issues related to intensive observations to be conducted during emergency situations.
In the first stage of SCOPE development, we aimed to enable to observe an area 4 km away. If it can be able to observe longer-distance area, the usefulness of SCOPE would increase. To demonstrate its possibility, we conducted experimental observation at the Mt. Fuji. Observations were conducted in the morning and afternoon of October 4, 2024. We applied InSAR processing to these data obtained in the morning and afternoon, and confirmed that interferograms were obtained even in the vicinity of 10 km. Although the coherence was slightly lower as the result from the interferometric pair of several hours, this could be due to effects such as heavy rain and multipath. Further investigation is necessary about it.
In situations of emergency observation, intensive observations may be conducted in a short period. In order to clarify the issues involved in such intensive observations, we conducted once-daily observations at three locations on Sakurajima for five consecutive days. To observe crustal deformation with higher temporal resolution, a ground-based real-aperture radar interferometer (GAMMA GPRI2) was installed at one of the sites, and observations were conducted every 5 minutes. The observations were carried out without any problems. In addition, eruptions occurred during the observation period, and there was ash fall at the observation sites, but it was possible to make observations even at such sites, and furthermore, there was no noticeable decorrelation in the resulted interferograms due to the ash fall. We will further analyze and investigate crustal deformation in the future.
In the first stage of SCOPE development, we aimed to enable to observe an area 4 km away. If it can be able to observe longer-distance area, the usefulness of SCOPE would increase. To demonstrate its possibility, we conducted experimental observation at the Mt. Fuji. Observations were conducted in the morning and afternoon of October 4, 2024. We applied InSAR processing to these data obtained in the morning and afternoon, and confirmed that interferograms were obtained even in the vicinity of 10 km. Although the coherence was slightly lower as the result from the interferometric pair of several hours, this could be due to effects such as heavy rain and multipath. Further investigation is necessary about it.
In situations of emergency observation, intensive observations may be conducted in a short period. In order to clarify the issues involved in such intensive observations, we conducted once-daily observations at three locations on Sakurajima for five consecutive days. To observe crustal deformation with higher temporal resolution, a ground-based real-aperture radar interferometer (GAMMA GPRI2) was installed at one of the sites, and observations were conducted every 5 minutes. The observations were carried out without any problems. In addition, eruptions occurred during the observation period, and there was ash fall at the observation sites, but it was possible to make observations even at such sites, and furthermore, there was no noticeable decorrelation in the resulted interferograms due to the ash fall. We will further analyze and investigate crustal deformation in the future.