日向灘地殻活動総合観測線による地殻変動連続観測

Abstract

Results of continuous observations of crustal movements at 6 observatories in observation network of crustal activities around the Hyuganada region of Kynshu, Southwest Japan, are described.Secular variations free from seasonal variation and shorter period disturbances of observed strains and tilts at each observatories are revealed with 365 days running mean procedure. At newly constructed stations, the initial drift in the continuous records of ground-strain and -tilt have decreased gradually. At Miyazaki Observatory, where the precipitation exceeds 3000 mm/year, the effects of rainfall cannot be removed completely, and averaged strain changes (365 days running mean) depend on annual precipitaion. Strain rates and principal strains are calculated from this secular variations.Principal strains at 2 observatories, Miyazaki and Isa, are coincident in direction with each other, which are extension in N-S and contraction in E-W direction.