Full Papers
Gravity Measurement in Oshima Island
1985 November
1986 Volume 37 Issue 4 Pages 271-280
Details
1986 Volume 37 Issue 4 Pages 271-280
A precise gravity survey in Izu-Oshima Island was carried out in November 1985 using the LaCoste & Romberg Model D gravity meter No.109. The measurements were made on the bench marks of the leveling route rounding the island which was established by the Geographical Survey Institute (GSI) in 1979 and on gravity points of the Earthquake Research Institute (ERI) and GSI as well as other several newly established stations. The accuracy of the measurements is estimated to be within ±10 μgal for the leveling route around the island and about ± 20 μgal for the inland mountainous route.
By comparing the results with the measurements made by GSI and ERI, it is found that gravity values in the island have a general tendency to decrease in the past several to 15 years. This is concordant with the fact that volcanic activity at Mt. Miharayama has been quiet in recent years.
