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

伊豆半岛东北部自1967年以来持续隆升。总隆升达30厘米。地震群经常发生在伊豆半岛的东部。伊豆半岛位于相模海槽和鹤河海槽之间，位于菲律宾海板块、太平洋板块和大陆板块三个板块的碰撞位置之上，地壳活动十分活跃。本研究的目的在于探讨隆升的机制及其与地震群的关系。主要结果如下：1。当隆升峰位于东部海岸（Futo地区）时就会发生地震群，而当隆升峰位于其他地方时则不会发生地震群。1987年以来，隆升加速，在喷发前靠近喷发点的地方加速加速，1989年7月13日发生了一次海底喷发。研制了新型多分量小型钻孔应变仪和新型便携式平行板弹簧倾斜仪，并在多个测点安装。随着从这些仪器中获得的数据的积累，预计将获得良好的结果。

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.