2009 Volume 55 Issue 3 Pages 325-339
An ocean bottom gravimeter was developed in 1996 for gravimetry on the deep seafloor. Although the control and logging units were originally installed in a pressure housing separated from the sensor unit, a few sea trials suggested unifying the system. Then the space for the sensor unit was enlarged with an additional cylinder, and all the units were installed in the single pressure housing. Seafloor gravimetry was carried out with the remodeled gravimeter on the shallow bottom off Shimokita Peninsula, Aomori Prefecture, in order to investigate the distribution of the intrusive rock that has not been exposed to surface. Detailed and seamless gravimetry was performed in the coastal area combined with the observation on land. As a result, the horizontal extension of the intrusive rock that has not been exposed to surface was confirmed based on gravity mapping with a precision of 0.05 mgal, and the effectiveness of the seamless gravity investigation became clear.
