Experimental challenge to estimate frictional properties of a plate boundary based on microseismicity

2017 Fiscal Year Final Research Report

• Project/Area Number: 15K05259
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Solid earth and planetary physics
• Research Institution: Tohoku University
• Principal Investigator: Yabe Yasuo 東北大学, 理学研究科, 准教授 (30292197)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: AE活動 / 断層摩擦 / 速度依存性 / 累積すべり量依存性 / 法線応力依存性

Outline of Final Research Achievements

Normal stress dependencies of evolution of the rate effect on frictional strength and AE activity were examined by laboratory experiments using granite specimens. For cumulative sliding distance smaller than a critical distance, the rate dependency of friction is positive, while that of the b-value of AE activity is negative. When the cumulative sliding distance reaches the critical distance, the rate dependence of friction turns to negative. At the same time, the rate dependence of the b-value of AE activity becomes negative. Higher the normal stress, the critical distance becomes smaller.
The evolutions of rate effects on the friction and the AE activity can be approximated by an exponential function to estimate a characteristic sliding distance required to reach a steady state. The characteristic sliding distance is inversely proportional to the normal stress, suggesting a work done by external force to evolve fault surface topographies by wear is independent of the normal stress.

Free Research Field

岩石力学