5:15 PM - 7:15 PM
[STT40-P06] Monitoring of the Azumayama Volcano by InSAR Analysis and Estimation of Pressure Source
Keywords:Azumayama volcano, InSAR, 2.5 dimentional analysis, pressure source estimation
The Azumayama volcano is one of the active volcanoes in Fukushima Prefecture. A phreatic eruption occurred in 1977. Continuous gas emissions and volcanic earthquakes are observed even now. The Volcanic Alert Level 2 has been issued for the Azumayama volcano three times during the past 11 years.
We have been working on monitoring the crustal deformation around the Azumayama volcano by using ALOS2/PALSAR-2 data. In this study, we conducted InSAR analysis using SAR data obtained from ALOS-2/PALSAR2 for September 2021 - August 2024. We used RINC (Ozawa et al., 2016) for the analysis. Additionally, we utilized the results of InSAR analysis for September 2020 - August 2023 (including data analyzed by Yabuki, 2023, UoA, GT) to perform 2.5D analysis and pressure source estimation. This allowed us to estimate crustal deformation of Azumayama volcano in quasi east-west and quasi up-down directions around the Azumayama volcano. Furthermore, based on the results of the 2.5D analysis, the position, volume and volume change of the pressure source were analyzed using the Mogi model (Mogi, 1958). The analysis was performed using MaGCAP-V (JMA, Earthquake and Volcano Research Department, Meteorological Research Institute, 2008).
The InSAR analysis results indicated a slight uplift of a few centimeters from September 2021 to July 2023. In contrast, a slight subsidence by a few centimeters was estimated for the period from July 2023 to November 2023. The results of the 2.5D analysis suggested that, from September 2020 to August 2023, crustal deformation occurred quasi-westward and quasi-upward directions by about 1-3 cm and 1-2 cm, respectively. On the other hand, the pair from August 2021 to August 2022 exhibited inconsistent crustal deformation, where further improvement of InSAR is expected for corresponding analysis pairs.
The pressure source estimation based on the results from 4 InSAR pairs among 6 pairs for September 2020 - August 2023 indicated the magma chamber locates within a radius of approximately 200-300 m from the Oana Crater. The estimated depths of the magma chamber were mostly within 150 m. As for volume change, expansions of variable amounts are estimated, while only one result based on the InSAR pair from August 2022 to August 2023 showed a very subtle contraction.
Acknowledgement:
PALSAR-2 SLC data are shared among PIXEL (PAL-SAR Interferometry Consortium to Study our Evolving Land surface) and provided from JAXA under a coop-erative research contract with ERI, Univ., Tokyo. Theownership of PALSAR-2 data belongs to JAXA.
The Meteorological Research Institute has provided us with MaGCAP-V (Earthquake and Volcano Research Department, Meteorological Research Institute, 2008), a software program to support analysis of crustal activity of volcanoes.
We have been working on monitoring the crustal deformation around the Azumayama volcano by using ALOS2/PALSAR-2 data. In this study, we conducted InSAR analysis using SAR data obtained from ALOS-2/PALSAR2 for September 2021 - August 2024. We used RINC (Ozawa et al., 2016) for the analysis. Additionally, we utilized the results of InSAR analysis for September 2020 - August 2023 (including data analyzed by Yabuki, 2023, UoA, GT) to perform 2.5D analysis and pressure source estimation. This allowed us to estimate crustal deformation of Azumayama volcano in quasi east-west and quasi up-down directions around the Azumayama volcano. Furthermore, based on the results of the 2.5D analysis, the position, volume and volume change of the pressure source were analyzed using the Mogi model (Mogi, 1958). The analysis was performed using MaGCAP-V (JMA, Earthquake and Volcano Research Department, Meteorological Research Institute, 2008).
The InSAR analysis results indicated a slight uplift of a few centimeters from September 2021 to July 2023. In contrast, a slight subsidence by a few centimeters was estimated for the period from July 2023 to November 2023. The results of the 2.5D analysis suggested that, from September 2020 to August 2023, crustal deformation occurred quasi-westward and quasi-upward directions by about 1-3 cm and 1-2 cm, respectively. On the other hand, the pair from August 2021 to August 2022 exhibited inconsistent crustal deformation, where further improvement of InSAR is expected for corresponding analysis pairs.
The pressure source estimation based on the results from 4 InSAR pairs among 6 pairs for September 2020 - August 2023 indicated the magma chamber locates within a radius of approximately 200-300 m from the Oana Crater. The estimated depths of the magma chamber were mostly within 150 m. As for volume change, expansions of variable amounts are estimated, while only one result based on the InSAR pair from August 2022 to August 2023 showed a very subtle contraction.
Acknowledgement:
PALSAR-2 SLC data are shared among PIXEL (PAL-SAR Interferometry Consortium to Study our Evolving Land surface) and provided from JAXA under a coop-erative research contract with ERI, Univ., Tokyo. Theownership of PALSAR-2 data belongs to JAXA.
The Meteorological Research Institute has provided us with MaGCAP-V (Earthquake and Volcano Research Department, Meteorological Research Institute, 2008), a software program to support analysis of crustal activity of volcanoes.