5:15 PM - 6:45 PM
[STT35-P03] Monitoring volcanic activity at Kuchino-Erabujima using ALOS-2 data
Keywords:ALOS-2, InSAR time series analysis, Kuchino-Erabujima, crustal deformation, volcano
Kuchino-Erabujima is a volcanic island located northwest of Yakushima, and is one of the most active volcanoes, with an explosive eruption accompanied by pyroclastic flows occurring most recently in February 2020. Since mid-June 2023, volcanic earthquakes with epicenters in shallow areas near the crater of Shindake and near Furudake have increased. Due to a further increase in volcanic earthquakes with epicenters in shallow areas near Furudake in late June 2023, the volcanic alert level for Kuchino-Erabujima was raised to 3 on June 27. For this reason, observations by ALOS-2 were conducted. Since then, intermittent volcanic earthquakes have continued, and ALOS-2 observations have been conducted more than 30 times by January 2024.
GSI conducts analysis immediately after the observations by ALOS-2 in order to monitor the transition of volcanic activities. The results of the analysis are provided to the Coordinating Committee for Prediction of Volcanic Eruption and other related organizations. ALOS-2 observations were conducted on June 30, immediately after the volcanic alert level was raised. InSAR analysis was conducted using the observation data. As a result, we detected a displacement approaching the satellite of about 4 cm within a range of several hundred meters around the crater of Furudake. The 2.5-dimensional analysis (Fujiwara et al, 2000) was performed using the results of the InSAR analysis with June 30 observing data and the another analysis with July 7 data. The results of the 2.5-dimensional analysis revealed an expansion trend around the Furudake crater. Furthermore, an InSAR time series analysis conducted using data from more than 30 observations, which have conducted since December 2021, detected displacements approaching the satellite of about 12 cm around the Furudake crater during the period from May to September 2023. In addition, a 2.5-dimensional analysis was conducted using the results of InSAR analysis and InSAR time series analysis. As a result, we detected an uplift of about 13 cm around the Furudake crater, a westward movement of about 10 cm on the west side of the Furudake crater, and an eastward movement of about 6 cm on the east side of the Furudake crater until September 2023.
All recorded eruptions on Kuchino-Erabujima have occurred in and around Shindake, and the last eruption in and around Furudake is thought to have occurred about 200 years ago (AIST, 2007). The crustal deformation detected by ALOS-2 had been limited to the Shindake area, and no clear deformation had been detected in the Furudake area prior to last year's volcanic activity. We believe that this analysis has yielded valuable results.
In this presentation, we will report and discuss the results of InSAR analysis and InSAR time series analysis using a series of observation data by ALOS-2, and the position and volume changes of the underground pressure sources of volcanoes estimated using these analysis results.
Acknowledgments: ALOS-2 data were provided based on the joint research agreement with Japan Aerospace Exploration Agency (JAXA) and under a cooperative research contract between GSI and JAXA. The ownership of ALOS-2 data belongs to JAXA.
GSI conducts analysis immediately after the observations by ALOS-2 in order to monitor the transition of volcanic activities. The results of the analysis are provided to the Coordinating Committee for Prediction of Volcanic Eruption and other related organizations. ALOS-2 observations were conducted on June 30, immediately after the volcanic alert level was raised. InSAR analysis was conducted using the observation data. As a result, we detected a displacement approaching the satellite of about 4 cm within a range of several hundred meters around the crater of Furudake. The 2.5-dimensional analysis (Fujiwara et al, 2000) was performed using the results of the InSAR analysis with June 30 observing data and the another analysis with July 7 data. The results of the 2.5-dimensional analysis revealed an expansion trend around the Furudake crater. Furthermore, an InSAR time series analysis conducted using data from more than 30 observations, which have conducted since December 2021, detected displacements approaching the satellite of about 12 cm around the Furudake crater during the period from May to September 2023. In addition, a 2.5-dimensional analysis was conducted using the results of InSAR analysis and InSAR time series analysis. As a result, we detected an uplift of about 13 cm around the Furudake crater, a westward movement of about 10 cm on the west side of the Furudake crater, and an eastward movement of about 6 cm on the east side of the Furudake crater until September 2023.
All recorded eruptions on Kuchino-Erabujima have occurred in and around Shindake, and the last eruption in and around Furudake is thought to have occurred about 200 years ago (AIST, 2007). The crustal deformation detected by ALOS-2 had been limited to the Shindake area, and no clear deformation had been detected in the Furudake area prior to last year's volcanic activity. We believe that this analysis has yielded valuable results.
In this presentation, we will report and discuss the results of InSAR analysis and InSAR time series analysis using a series of observation data by ALOS-2, and the position and volume changes of the underground pressure sources of volcanoes estimated using these analysis results.
Acknowledgments: ALOS-2 data were provided based on the joint research agreement with Japan Aerospace Exploration Agency (JAXA) and under a cooperative research contract between GSI and JAXA. The ownership of ALOS-2 data belongs to JAXA.