Development of the Intelligent Compact Conical-ended Borehole Overcoring method and 3D JAPAN STRESS MAP

本研究的目的是开发高精度的地应力测量方法，揭示地应力状态。我们在2011年东北地震后进行了地应力测量，并与地震前的结果进行了对比。主要研究成果如下：(1)研制了旋风紧凑型数据记录仪和锥端向下紧凑型井眼取心应变片粘接装置。(2)在2011年东北大地震后进行了三次地应力测量。通过与震前结果的对比，得出了非常重要的结果，对编制日本三维地应力图具有重要意义。这项研究的结果表明，在固定位置进行测量，即使是在浅层，也可以有效地研究地壳应力与地震之间的关系。

This study was conducted for purposes of development of high-precision in-situ rock stress measurement method and the information disclosure of the in-situ rock stress state. We carried out the in-situ stress measurement after the 2011 Tohoku-oki earthquake and performed the comparison with the results before the earthquake. The results are summarized as follows:(1) The Cyclone Compact Data logger and the bonding device of the strain-cell unit for the Downward Compact Conical-ended Borehole Overcoring method were developed. (2) The in-situ stress measurements were performed three times after the 2011 Tohoku-oki earthquake. We obtained very important results to develop of 3D JAPAN STRESS MAP from the comparison with the results before the earthquake. The results of this study suggest that measurements at a fixed position, albeit at a shallow depth, can be effective for studying the relation between crustal stress and earthquakes.