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タイトル: | Groundwater oxygen isotope anomaly before the M6.6 Tottori earthquake in Southwest Japan |
著者: | Onda, Satoki Sano, Yuji Takahata, Naoto Kagoshima, Takanori Miyajima, Toshihiro Shibata, Tomo https://orcid.org/0000-0002-2416-1541 (unconfirmed) Pinti, Daniele L. Lan, Tefang Kim, Nak Kyu Kusakabe, Minoru Nishio, Yoshiro |
著者名の別形: | 柴田, 智郎 |
発行日: | 19-Mar-2018 |
出版者: | Springer Nature |
誌名: | Scientific Reports |
巻: | 8 |
論文番号: | 4800 |
抄録: | Geochemical monitoring of groundwater in seismically-active regions has been carried out since 1970s. Precursors were well documented, but often criticized for anecdotal or fragmentary signals, and for lacking a clear physico-chemical explanation for these anomalies. Here we report – as potential seismic precursor – oxygen isotopic ratio anomalies of +0.24‰ relative to the local background measured in groundwater, a few months before the Tottori earthquake (M 6.6) in Southwest Japan. Samples were deep groundwater located 5 km west of the epicenter, packed in bottles and distributed as drinking water between September 2015 and July 2017, a time frame which covers the pre- and post-event. Small but substantial increase of 0.07‰ was observed soon after the earthquake. Laboratory crushing experiments of aquifer rock aimed to simulating rock deformation under strain and tensile stresses were carried out. Measured helium degassing from the rock and ¹⁸O-shift suggest that the co-seismic oxygen anomalies are directly related to volumetric strain changes. The findings provide a plausible physico-chemical basis to explain geochemical anomalies in water and may be useful in future earthquake prediction research. |
著作権等: | © The Author(s) 2018. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. |
URI: | http://hdl.handle.net/2433/234718 |
DOI(出版社版): | 10.1038/s41598-018-23303-8 |
PubMed ID: | 29555988 |
出現コレクション: | 学術雑誌掲載論文等 |
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