抄録
The summary of distance measurements of six base-line networks in the western Japan, made with a Geodimeter model 6 since 1968, is presented. Precise measurements of three lines in a tunnel of the Amagase crustal deformation observatory were repeatedly made during 1970-1978. As a result of these measurements, strain accumulations exhibited the rates of (2.6-1.5)×10-6/year for the length of 400-1700 m. And the strain accumulation obtained from continuous records of a super-invar bar extensometer installed at the same turnnel exhibited the rate of 1.9×10-6/year for the length of 40 m. Both results are consistent within the observational error. At the Donzurubo and Wakayama networks, trend of strain accumulations obtained from electro-optical distance measurements are also consistent with those from continuous observations by extensometers.
