Mechanism of transient electric activities associated with rock failure

岩石破坏瞬态电活动机制

• 批准号: 13640459
• 负责人: TSUTSUMI Akito
• 金额: $ 2.62万
• 依托单位: KYOTO UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640459/
• 关键词: Fracto-emission; Electromagnetic anomaly; Rock fracture; Tri-axial experiment; 三軸試験機; 圧力容器

Despite the increasing interest in fracto-emission phenomena in rocks, particularly in connection with the electromagnetic anomalies observed possibly related to earthquakes, experimental data reported on the topic has so far been limited. In this study, uni-axial and tri-axial compression tests of rocks have been conducted and fracture induced electric signals were measured as a transient electric charge signal and as an electric potential difference between two electrodes of thin copper plates, between which the tested rock specimens sit. Our experimental results showed that in both types of the experiments : (1) Electric charge signals that appeared prior to the main failure of rock specimens were detected only for granitic rocks of which main constituent mineral is quartz, and (2) At the moment of the main failure, however, electric charge signal and intense electric field change were observed for all tested specimens irrespective to the existence of quartz grains. For quartz-bearing rocks such as granite, the piezoelectric behavior of quartz should contribute to some extent to the electric signals observed during the precursory period prior to fracture of dry rocks. Our results, however, confirmed that there are other important contributing factors.

尽管人们对岩石中的破碎发射现象越来越感兴趣，特别是与观察到的可能与地震有关的电磁异常有关，但迄今为止报告的有关该主题的实验数据仍然有限。在这项研究中，进行了岩石的单轴和三轴压缩试验，并以瞬态电荷信号和薄铜板两个电极之间的电势差的形式测量了断裂引起的电信号，测试的岩石样本位于两个电极之间。我们的实验结果表明，在两种类型的实验中：（1）仅在主要成分矿物为石英的花岗岩中检测到岩石样本主要破坏之前出现的电荷信号，以及（2）然而，在主要破坏瞬间，无论是否存在石英颗粒，所有测试样本都观察到电荷信号和强烈的电场变化。对于花岗岩等含有石英的岩石，石英的压电行为应该在一定程度上有助于在干燥岩石破裂之前的前兆时期观察到的电信号。然而，我们的结果证实还有其他重要的影响因素。

项目成果

Tsutsumi, A., Tanaka, S., Shirai, N., Enomoto, Y: "Electric signals accompanying fracture of granite"Japanese Journal of Applied Physics. (印刷中).

Tsutsumi, A.、Tanaka, S.、Shirai, N.、Enomoto, Y：“伴随花岗岩断裂的电信号”日本应用物理学杂志（正在出版）。

Hashimoto, H., Enomoto, Y., Tsutsumi, A., Kasahara, M.: "Anomalous geo-electric signals associated with recent seismic activities in Tsuluba and volcanic activity at Mt.Usu in Hokkaido"Seismic Electromagnetics, Lithosphere-Atmosphere-Ionosphere Coupling,

Hashimoto, H.、Enomoto, Y.、Tsutsumi, A.、Kasahara, M.：“与近期津鲁巴地震活动和北海道有珠山火山活动相关的异常地电信号”地震电磁学、岩石圈-大气-

A., Tsutsumi, S., Tanaka, N., Shirai, and Y., Enomoto: "Electric signals accompanying fracture of granite"Japanese Journal of Applied Physics. ess.

A.、Ttsutsumi, S.、Tanaka, N.、Shirai 和 Y.、Enomoto：“伴随花岗岩断裂的电信号”日本应用物理学杂志。