Establishment of an Absolute Gravity Network in East-Asia and Precise Monitoring of Gravity Changes

我们参与了IAG的亚太空间地球动力学（APSG）项目合作活动和亚洲及太平洋地理信息系统基础设施常设委员会（PCGIAP）的工作计划，合作建立了东亚和东南亚绝对重力标准站网络（AGSSN-ESEA），配备FG-5绝对重力仪。在2002 - 2005年期间，我们已经在中国的武汉、南宁、上海、北京、昆明、拉萨、香港乌鲁木齐、Xi和西宁，台湾的新竹，印度尼西亚的万隆、日惹芝比农和坤甸，马来西亚的吉隆坡和亚庇，泰国的曼谷和澄迈，以及日本的京都、江ashi、松代、神冈、室户、阿索、米祖伊和那霸。在此次活动中，我们在印度尼西亚、马来西亚和菲律宾进行了首次AG测量，并为这些国家建立国家重力标准做出了贡献。2003- 2004年，我们在澳大利亚的珀斯和堪培拉以及南极的昭和站进行了绝对重力测量，并将武汉、北京、香港、新竹和京都等地FG-5型重力仪的绝对重力值进行了比较。结果表明，各仪器的测量值差异最大为11μGal。在武汉、万隆、京都、江ashi、松代和神冈等地，我们通过SG和AG的相互比对，确定了精度在0.1%以内的SG校准因子，我们期望通过AGSSN-ESEA各站每隔5 ~ 10年的重复AG测量，可以探测到大陆和岛弧之间1cm量级的相对垂直运动。

Taking part in the Asia-Pacific Space Geodynamics (APSG) Project cooperation campaigns in IAG and the work plan in the Permanent Committee on GIS Infrastructure for Asia & the Pacific (PCGIAP), we have collaborated to establish the Absolute Gravity Standard Station Network in East Asia and South-East Asia (AGSSN-ESEA) with FG-5 absolute gravimeters. During the period from 2002 to 2005, we have already determined absolute gravity values in the order of μGal at Wuhan, Nanning, Shanghai, Beijing, Kunming, Lhasa, Hong-Kong Wulumuqi, Xi'an and Xining in China, Hsinchu in Taiwan, Bandung, Yogyakarta Cibinong and Pontianak in Indonesia, Kuala Lumpur and Kota Kinabalu in Malaysia, Bangkok and Cheng-Mai in Thailand, and Manila in Philippines as well as Kyoto, Esashi, Matsushiro, Kamioka, Muroto, Aso, Mizunami and Naha in Japan. In this campaign, we performed first AG measurements in Indonesia, Malaysia and Philippines and contributed to establish national gravity standards in these countries. As an extension of this campaign in the southern hemisphere, we have conducted absolute gravity measurements in Perth and Canberra in Australia, and the Syowa Station in Antarctica in 2003-2004.As a result of comparison of AG values obtained from different FG-5 meters in Wuhan, Beijing, Hong Kong, Hsinchu and Kyoto, it was revealed that difference in measured values depending on each instrument is 11μGal at the most. In Wuhan, Bandung, Kyoto, Esashi, Matsushiro and Kamioka, we have determined SG calibration factors within the accuracy of the order of 0.1% from inter-comparison of SG and AG meters.We are expecting that relative vertical movements between the continent and island arc can be detected in the order of 1cm by the repeated AG measurements at stations in AGSSN-ESEA at interval of 5 to 10 years.