Groundwater helium anomaly reflects strain change during the 2016 Kumamoto earthquake in Southwest Japan

• DOI: 10.1038/srep37939
• Publication Date: 2016-11-29T10:22:01Z
• Authors: Yuji Sano; Naoto Takahata; Takanori Kagoshima; Tomo Shibata; Tetsuji Onoue; Dapeng Zhao
• Keywords: Hypocenter; Strain gauge; Noble gas; Anomaly (physics)

Abstract Geochemical monitoring of groundwater and soil gas emission pointed out precursor and/or coseismic anomalies noble gases associated with earthquakes, but there was lack plausible physico-chemical basis. A laboratory experiment rock fracturing conducted, is no quantitative connection between the results observation in field. We report here deep helium related to 2016 Kumamoto earthquake, which an inland crustal earthquake a strike-slip fault shallow hypocenter (10 km depth) close highly populated areas Southwest Japan. The observed isotope changes, soon after are quantitatively coupled volumetric strain changes estimated from model, can be explained by experimental studies degassing during compressional loading samples. Groundwater considered as effective gauge. This suggests first linkage geochemical seismological observations may open possibility develop new system detect possible change prior hazardous regions where conventional borehole meter not available.