油壼における水管傾斜計観測と水準測量との比較

抄録

Water-tube tiltmeter observations have been conducted at the Aburatsubo Crustal Movement Observatory since 1949. The present paper reviews the data accumulated in the past twenty years in order to examine if the station observation of this type can monitor the crustal movements satisfactorily or not. The Miura Peninsula area, in which the Aburatsubo station is located, is particularly suitable for this purpose, because the G. S. I's data of frequent relevelling and of mareographic observation are available for comparison. Following are the conclusions thus obtained: (i) Gradual westward tilting of the ground, which was recorded at Aburatsubo for the peiriod 1949-1960, turn to active eastward tilting about 1961. The basic mode of this movements, particularly the active eastward tilting since 1961, is witnessed by the levellings in the southern part of the peninsula. Similar mode of land movements is also noticed on the mareographic records at Aburatsubo and Mera as well as on the tiltmeter record at Nokogiriyama, where the latter two stations are located at an adjacent peninsula. (ii) As to the detailed features, however, tiltmeter data do not agree with the geoditic data necessarily. The writer can hardly explain the causes of disagreement, but he tenta-tively considers that it might be attributed partly to sea level anomalies which result in local tilting of the coastal ground by loading.