15:30 〜 17:00
[SGD01-P02] 富士山の重力観測網の構築とその活用
キーワード：重力、富士山、火山、重力モニタリング、絶対重力測定、重力計検定
Mount Fuji, often recognized as a symbol of Japan, is visited by a large number of tourists and hikers. At the same time, it is also a volcano which is difficult to predict where the crater will appear, so the improvement of the volcano observation system is an issue in order to safely evacuate a large number of people. Although the volcanic activity of Mt. Fuji is currently quiet, Mt. Fuji Research Institute (MFRI) started construction of a gravity observation network in 2018 with the aim of making it easier to understand the volcanic phenomenon through multifaceted observations.
The observation design for detecting volcanic signals is as follows. We set up a reference gravity station in MFRI at the foot of the mountain and installed several gravity stations along the way to the 5th station for campaign observations. By repeating the campaign observations, we may be able to detect changes in gravity around the crater appearance area. The Geospatial Information Authority of Japan conducts absolute gravity measurement at the MFRI reference point, and MFRI station is now operated as a Fundamental Gravity Station. In addition, continuous observation by gPhone gravimeters has been started at MFRI (#163) and the 4th station (SL4ST, #153). We explore changes under the volcano by combining periodic absolute gravity measurements at reference stations, continuous observations and campaign observations with relative gravimeters.
Taking advantage of the characteristics of this Mt. Fuji gravity observation network, various academic efforts are also possible. First, the large gravity difference between the MFRI and SL5ST allows calibration of relative gravimeters. For this purpose, we performed absolute gravity measurements at the SL5ST station last year. In recent years, many researchers have visited Mt. Fuji to use this calibration line. Various verification measurements are possible at the MFRI station with less noise and two measurement bases. We also report on various observation efforts using the Mt. Fuji gravity observation facility.
The observation design for detecting volcanic signals is as follows. We set up a reference gravity station in MFRI at the foot of the mountain and installed several gravity stations along the way to the 5th station for campaign observations. By repeating the campaign observations, we may be able to detect changes in gravity around the crater appearance area. The Geospatial Information Authority of Japan conducts absolute gravity measurement at the MFRI reference point, and MFRI station is now operated as a Fundamental Gravity Station. In addition, continuous observation by gPhone gravimeters has been started at MFRI (#163) and the 4th station (SL4ST, #153). We explore changes under the volcano by combining periodic absolute gravity measurements at reference stations, continuous observations and campaign observations with relative gravimeters.
Taking advantage of the characteristics of this Mt. Fuji gravity observation network, various academic efforts are also possible. First, the large gravity difference between the MFRI and SL5ST allows calibration of relative gravimeters. For this purpose, we performed absolute gravity measurements at the SL5ST station last year. In recent years, many researchers have visited Mt. Fuji to use this calibration line. Various verification measurements are possible at the MFRI station with less noise and two measurement bases. We also report on various observation efforts using the Mt. Fuji gravity observation facility.