屯鶴峯地殻変動観測所における地殻変動観測-1980-1989-

At the Donzurubo Crustal Movement Observatory, continuous observations of ground strainsand tilts were interrupted by civil engineering work in vault. After civil engineering work,anomalous variations of ground strains and tilts appeared for about three years.It appears that trend of secular variations of strains changed in 1985 to 1986. Variationsof extention were showed in all direction till 1985-1986. Its variations of extensions disappearedafter that and variations of contructions appeared in east-west direction. This is consistent withthe result of erectro-optical distance measurements.