日本小笠原群岛火山岛的地下电性结构。

Subterranean electrical structure of Kozu-shima volcanic island, Japan.

机构信息

Earthquake Prediction Research Center, Tokai University, Shizuoka, Japan.

出版信息

Proc Jpn Acad Ser B Phys Biol Sci. 2010;86(9):914-9. doi: 10.2183/pjab.86.914.

DOI:10.2183/pjab.86.914

PMID:21084774

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC3035923/

Abstract

Following the electric current injection experiment carried out in 2009, a VLF-MT (Very Low Frequency Magnetotelluric) survey has been conducted in Kozu-shima Island to obtain further information on the subterranean electrical structure that might help understanding the results of our monitoring of geoelectric potentials. A number of VAN-type pre-seismic geoelectric potential anomalies were observed in 1997-2000, even showing a remarkable "Selectivity". However, similar pre-seismic anomalies were not observed during the Izu-Island volcano-seismic swarm 2000. All these observations would require extremely high degree of heterogeneity in the subterranean electrical structure of the volcanic island and its possible time changes. Several correlations between the results of this survey and the volcanic geology of the island and ground water distribution were found. Further investigation is needed for a complete explanation of the observed phenomena.

摘要

在 2009 年进行了电流注入实验之后，我们在小笠原群岛进行了甚低频大地电磁（VLF-MT）测量，以获取有关地下电性结构的进一步信息，这有助于我们理解对大地电势能监测的结果。在 1997 年至 2000 年期间，观测到了许多 VAN 型地震前兆地电场异常，甚至表现出显著的“选择性”。然而，在 2000 年伊豆群岛火山地震群期间，并没有观测到类似的地震前兆异常。所有这些观测结果都需要火山岛及其地下电性结构的高度非均质性及其可能的时间变化。在这次调查的结果与该岛的火山地质和地下水分布之间发现了一些相关性。需要进一步研究才能对所观察到的现象做出完整的解释。