[S-GD01] Geodesy and Global Geodetic Observing System

[SGD01-P01] Absolute gravity measurements in Mt. Fuji with two FG5 gravimeters in September 2022: establishment of calibration line for relative gravimeters and calibration of instrumental offsets of FG5 gravimeters

*Yuichi Imanishi¹, Ryuichi Nishiyama¹, Ryo Honda² (1.Earthquake Research Institute, The University of Tokyo, 2.Mount Fuji Research Institute, Yamanashi Prefectural Government)

Keywords:Mt. Fuji, absolute gravity measurement, instrumental offset

Absolute gravity measurements were conducted in Mt. Fuji using two sets of FG5 absolute gravimeters (serial numbers #109 and #241) in September 2022. First, the two gravimeters were operated simultaneously at the foot and the halfway point (the 5th station) of the mountain in order to determine the difference in gravity between the two points. Next, the two gravimeters were subject to comparative measurements at the foot of the mountain in order to calibrate relative instrumental offsets. From these experiments, values of gravity difference of (294,745.03 ± 0.25) µGal (at 130.0 cm above the floor) and (294,656.04 ± 4.13) µGal (on the floor) were established between the foot and the halfway point of the mountain. This will provide an ideal opportunity for precisely calibrating the sensitivities of relative gravimeters.