Comparison Research on Gravity Changes in Indonesia, China and Japan by Employing Superconducting Gravimeters

利用超导重力仪进行精确的重力测量有望成为探测地球流体核振荡或与地震和火山活动有关的构造运动引起的长期重力变化所引起的非常微弱的信号的有效措施。全球地球动力学计划（GGP）是在IUGG和IAG的赞助下建立的一个全球性的SG网络，该计划是一个观测地球重力场时间变化的国际计划。该网络的数据分发始于1997年。当然，利用SG全球网络的数据改进以地球深部为重点的全球地球动力学研究也很重要。另一方面，利用印度尼西亚、中国和日本的SG资料，通过比较海潮对这些地区固体潮观测的负荷效应，研究东亚地区地壳上地幔物理性质和结构的区域特征。京都大学继续 ...更多信息 自1988年以来使用两个SG进行精确的重力观测。1997年，我们将两个全球战略之一从京都转移到印度尼西亚的万隆。从那时起，在京都大学和印度尼西亚火山调查局的密切合作下，在万隆继续进行SG观测。在这项研究中，我们，日本调查人员每半年访问万隆的SG维护，和印度尼西亚调查人员每年访问京都分析SG数据和讨论的重力变化问题，在构造活动区沿着岛弧。首席研究员（S。竹本一行访问了中国科学院大地测量与地球物理研究所。Sci. 1999年11月在武汉与中方研究人员讨论了利用超导重力仪和绝对重力仪进行东亚地球动力学合作研究的问题。我们可以建立一个万隆、武汉和京都超导重力仪的数据集。通过对这些资料的比较，可以看出海潮对固体潮观测负荷效应的区域差异。少

Precise gravity measurements using superconducting gravimeters (SGs) are expected to be an effective measure for detection of very weak signals caused by oscillations in the Earth's fluid core, or long-term gravity changes due to tectonic motions related to seismic and volcanic activities. A global network of SGs was set up by Global Geodynamic Project (GGP), an international program of observations of temporal variations in the Earth's gravity field, under the sponsorship of IUGG and IAG. Data distribution of the network began in 1997. It is of course important to improve global geodynamic studies focused on Earth's deep interior using data of the SG global network. On the other hand, it is desired to investigate regional characteristics of physical properties and structures in crust and upper mantle in East Asia using SG data in Indonesia, China and Japan by means of comparison of loading effects of ocean tides on Earth tide observation in these areas. Kyoto University has carried on … More precise gravity observation using two SGs since 1988. In 1997, we shifted one of the two GSs from Kyoto to Bandung, Indonesia. Since then, SG observation in Bandung has been continued under close cooperation between Kyoto Univ. and Volcanological Survey of Indonesia. In this study, we, Japanese investigators visited Bandung every half a year for maintenance of the SG, and Indonesian investigators visited Kyoto every year to analyze the SG data and to discuss problems on gravity changes in tectonically active regions along island arcs. The head investigator (S. Takemoto) visited the Institute of Geodesy and Geophysics, Chinese Acad. Sci. in Wuhan in November 1999 and discussed with Chinese investigators our cooperative research of geodynamics in East Asia using superconducting gravimeters and absolute gravimeters. We could establish a data set of the superconducting gravimeters in Bandung, Wuhan and Kyoto. As a result of comparison of these data, regional difference of loading effects of ocean tides on Earth tide observation can be indicated. Less