抄録
The Fujigawa Crustal Movement Observatory has worked out continuous observation of crustal deformation since July 1970. The observation vault, which is adjacent to the southern end of the Itoigawa-Shizuoka tectonic line, is equipped with three components of silica-tube extensometers (40 m in length), two components of water-tube tiltmeters (manual reading type, 40 m in length) and a set of small-size borehole tiltmeters. These instruments, except the water-tube tiltmeters of manual reading type, are sensed with differential transformers and are connected to analogue chart recorders as well as to a digital recording system. Later, in April 1975, a set of ultrasonic watertube tiltmeters (40 m in length) were added for the purpose of automatizing tilt observation. Details of the instrumentation together with structures of the vault are given in the first half of the paper. The recording system consists of a digital data acquisition system and three analogue recorders, one of which is used as a recorder of strainseismogram. Processing of the obtained data for derivation of secular change of the earth's strain and tilt is achieved by following three steps. First step is to debug the original paper tape which is obtained from the digital recording system. Second is to produce the edited monthly paper tape using data-typewriter referring to the result in the first step and, if necessary, to analogue records. Last step is to process the edited paper tape to obtain final result. The observational results, thus obtained, will be given in the next paper.
