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[SVC31-P12] Deformations Detected by Precise Levelling and GNSS Campaign Surveys in the Hakone volcano (2015-2021)
Keywords:Hakone Volcano, Precise Leveling Survey, GNSS
We conducted the precise leveling and the GNSS campaign surveys in the Hakone volcano. and discussed deformations in the period from 2015 to 2021.
The leveling routes of about 11 km with 41 benchmarks were established on the northern flank of central cone of Hakone volcano in 2015. The main route was extended from GEONET Hakone (Ninodaira) to the Togendai ropeway station. In order to improve the spatial layout of the benchmarks, a branched leveling route extended to Owakudani was established. We conducted the precise leveling surveys in December 2015, September 2016, December 2017, December 2018, December 2019, December 2020 and December 2021.
The GNSS campaign surveys were conducted on the four observation points around the leveling route in December 2017, December 2018, December 2019, December 2020 and December 2021. Deformations of not only the four campaign sites but also two continuous GNSS stations (Owakudani and Hakone) were calculated using the RTKLIB (Takasu et al.,2007).
In the period of December 2020- September 2021, the subsidence of 8mm was detected with respect to the GEONET Hakone on the Owakudani, and the small uplift of 2mm was detected around the junction of Owakudani.
Then, in the period between December 2015 and December 2021, the subsidence of 65mm and the uplift of 12mm were detected in the Owakludani and the junction of Owakudani, respectively.
Since GEONET Hakone is too close to accept as a reference point for the vertical deformation in Hakone volcano, we used GEONET Atsugi as the reference point. The GEONET Hakone showed the uplift of 10mm with respect to the GEONET Atsugi in the period from December 2020 to September 2021. Therefore, the uplift of 12mm was detected with respect to the GEONET Atsugi around the junction of Owakudani in this period.
The time series of the vertical deformations with respect to the GEONET Atsugi shows upward trend in the periods of 2016-2019 and 2020-2021. Slight increases of seismic activity were observed in 2019 and 2020.
Although subsidence was continued at the Owakudani in the period of 2016-2020, the small uplift was detected in period from December 2020 to December 2021.
In Owakudani, horizontal deformation of 42mm with East-Southeast direction was calculated with respect to the GEONET Atsugi in the period of 2017-2020. In other stations, horizontal deformations with the East-Southeast direction were also detected.
The leveling routes of about 11 km with 41 benchmarks were established on the northern flank of central cone of Hakone volcano in 2015. The main route was extended from GEONET Hakone (Ninodaira) to the Togendai ropeway station. In order to improve the spatial layout of the benchmarks, a branched leveling route extended to Owakudani was established. We conducted the precise leveling surveys in December 2015, September 2016, December 2017, December 2018, December 2019, December 2020 and December 2021.
The GNSS campaign surveys were conducted on the four observation points around the leveling route in December 2017, December 2018, December 2019, December 2020 and December 2021. Deformations of not only the four campaign sites but also two continuous GNSS stations (Owakudani and Hakone) were calculated using the RTKLIB (Takasu et al.,2007).
In the period of December 2020- September 2021, the subsidence of 8mm was detected with respect to the GEONET Hakone on the Owakudani, and the small uplift of 2mm was detected around the junction of Owakudani.
Then, in the period between December 2015 and December 2021, the subsidence of 65mm and the uplift of 12mm were detected in the Owakludani and the junction of Owakudani, respectively.
Since GEONET Hakone is too close to accept as a reference point for the vertical deformation in Hakone volcano, we used GEONET Atsugi as the reference point. The GEONET Hakone showed the uplift of 10mm with respect to the GEONET Atsugi in the period from December 2020 to September 2021. Therefore, the uplift of 12mm was detected with respect to the GEONET Atsugi around the junction of Owakudani in this period.
The time series of the vertical deformations with respect to the GEONET Atsugi shows upward trend in the periods of 2016-2019 and 2020-2021. Slight increases of seismic activity were observed in 2019 and 2020.
Although subsidence was continued at the Owakudani in the period of 2016-2020, the small uplift was detected in period from December 2020 to December 2021.
In Owakudani, horizontal deformation of 42mm with East-Southeast direction was calculated with respect to the GEONET Atsugi in the period of 2017-2020. In other stations, horizontal deformations with the East-Southeast direction were also detected.