活断層の重力調査(3) : 越生-高麗本郷断層と立川断層北部

概要

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埼玉県南西部と束京都西部に約360点の重力測定を実施し,越生-高麗本郷断層と立川断層に関連する重力異常リニアメン卜を検出した.とくに立川断層付近の稠密な重力探査によって,同断層北部は北東側隆起・南西側沈降の可能性があると指摘した.Gravity measurements were made at about 360 points in the southwestern part of Saitama Prefecture and in the western part of Tokyo City for the purpose of finding anomalous gravity field disturbances regarding the Ogose-Komahongo and the Tachikawa faults. We extracted lineaments parallel to the Ogose-Komahongo fault from the highpass-filtered Bouguer anomaly map. The Tachikawa fault is considered to be the source of a destructive earthquake which will cause much damage to the western part of Tokyo City. It is important from this point of view to intensify geophysical observations for monitoring the fault movements. One of the most fundamental prediction-oriented studies is to clarify the fault structure by gravity as well as geological surveys. The present gravity survey concludes that the Tachikawa fault is a normal fault dipping southwestwards.
東京大学地震研究所,Earthquake Research Institute, University of Tokyo,地震研究所の論文
1988-06-30