Investigation to clarify a mechanism of anomalous uplift on the Izu peninsula

伊豆半岛东北部自1967年以来持续隆起。总抬升量达30 cm。伊豆半岛东部近海经常发生震群。伊豆半岛位于相模海槽和骏河海槽之间，位于菲律宾海板块、太平洋板块和大陆板块三大板块碰撞部位之上，地壳活动十分活跃。探讨隆升机制及其与震群的关系是本研究的目的。主要结果如下：1.当隆起峰位于东海岸时，发生震群2.在1987年以来的抬升加速和喷发前靠近喷发点的点的加速之后，7月13日发生了海底喷发，1989.3.研制了新型多分量小钻孔应变仪和新型平行板簧便携式倾斜仪，并在多个台站安装。随着从这些仪器获得的数据的积累，预期会有良好的结果。

Northeast part of Izu peninsula continues to uplift since 1967. And total uplift reaches to 30 cm. Earthquake swarms often happen at off eastern part of the Izu peninsula. The Izu peninsula is located between the Sagami trough and the Suruga trough and above the place of collision of three plates ,namely Philippine sea plate, Pacific ocean plate and Continental plate so that crustal activity is very active. To investigate a mechanism of uplifting and relationship with earthquake swarm is the purpose of this study. The main results is as follows.1.An earthquake swarm occurs when the uplift peak is located at the east coast (Futo area) and does not occur when it is located elsewhere.2.After acceleration of the uplift from 1987 and more acceleration at points close to the erupted point before a eruption, a submarine eruption occurred on July 13,1989.3.New multi-component small borehole strain meters and new portable tiltmeters with parallel plate springs are developed and set up at several stations. Well results will be expected with accumulation of data obtained from those instruments.