日本-インドネシア国際重力結合とジャワ島西部における重力測定

Abstract

International gravimetric connection between Japan, Singapore and Indonesia was carried out with two LaCoste & Romberg gravimeters (model G) during the period from October 11 to November 2, 1993. In Singapore, gravity measurements were performed at three gravity stations registered on IGSN 71 (International Gravity Standardization Net 1971) and at another seven stations in this investigation. In Indonesia domestic gravimetric connection was carried out along the route of Jakarta-Bogor-Bandung by measuring gravity at nine gravity stations: Three stations belong to BAKOSURTANAL (National Agency for Surveys and Mapping of Indonesia), gravity values at two stations which belong to Geological Survey of Indonesia had been linked to IGSN 71, one station is GPS observation site which belongs to GPS survey network established in November 1991 by DPRI and ITB (Bandung Technological Institutes) in order to monitor crustal movements associated with active volcanoes and with active faults in West Jawa, and the other three are temporal stations for the convenience in the present study.Precise gravity measurements were performed along the base (or calibration) line which had been arranged by BAKOSURTANAL from Bandung to Subang at about 40km north-north-eastward from Bandung, in the range of gravity difference of 276 mgal.In this investigation, three GPS observation sites, which belong to the same GPS network mentioned above, along or near the route were connected gravimetrically to the base line. And another gravity measurements were performed at the other eight GPS observation sites which belong to also the same GPS network mentioned above.Obtained results will contribute to improve the accuracy of gravity measurements in Indonesia.