Identification of recent fault activity by measurement of hydration thickness using quartz from faults

2016 Fiscal Year Final Research Report

• Project/Area Number: 25350500
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Natural disaster / Disaster prevention science
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: NIWA Masakazu 国立研究開発法人日本原子力研究開発機構, バックエンド研究開発部門 東濃地科学センター, 研究副主幹 (90421685)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: 石英 / 水和 / 断層 / 活動性 / 地質学

Outline of Final Research Achievements

We focused on hydration of quartz in faulted rocks to identify recent fault activity. Fault activity possibly facilitates a growth of the quartz hydration layer, though hydration rate of quartz is generally too slow. In this study, secondary ion mass spectrometry (SIMS) analysis was applied to examine an influence of fault activity on the quartz hydration.
Based on the analyses for quartz from both faulted and unfaulted rocks in chert and granite, significant increase of hydrogen ion concentration along shiny fault planes was clear compared to natural, flat surfaces without fault slip. The SIMS analysis could be applicable for the estimation of hydration thickness of quartz along faults as well as the measurement of obsidian hydration thickness on the archaeological studies. The tests for still more samples should be further studies to examine geochronological application for fault activity.

Free Research Field

地質学