Absolute and relative gravity values were measured in the northern part of Kumamoto Prefecture in August 2018, in order to calibrate the scale factors of relative gravimeters and to observe spatiotemporal gravity variations in this area. Absolute gravity data were collected at two gravity points, Mashiki and HondoA (184 and 1166 m altitude, respectively), and both absolute gravity values were determined with about 2.6 μGal precision. The absolute gravity values and simultaneously measured relative gravity data were utilized in estimating the scale factors of five relative gravimeters under the least-square approach; accordingly, the scale factors were determined in the range of 0.996992 (LaCoste & Romberg D58) to 1.002390 (Scintrex CG6-18010054) within about 8×10(-5) precision. By comparing the gravity values with past values, the absolute gravity at Mashiki was found to have decreased by 27 μGal since August 2016 because of ground uplift after the 2016 Kumamoto earthquake and hydrological mass decrease. In contrast, the gravity values at HondoA were found to have increased by 85 μGal since 2000, mainly because of ground subsidence associated with the 2016 Kumamoto earthquake and magma chamber deflation under Aso volcano.
雑誌名
東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo
巻
94
号
1-4
ページ
13 - 28
発行年
2019
ISSN
00408972
書誌レコードID
AN00162258
著者版フラグ
publisher
出版者
東京大学地震研究所
出版者別名
Earthquake Research Institute, The University of Tokyo
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熊本県北部における絶対重力測定および相対重力計のスケールファクター検定（2018年8月）
IHO941402.pdf
(2.99MB)
