Interpretation of the generation mechanisms of slow earthquakes examined by friction experiments on subduction zone materials

2015 Fiscal Year Final Research Report

• Project/Area Number: 25800279
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Geology
• Research Institution: Shizuoka University
• Principal Investigator: Hirauchi Ken-ichi 静岡大学, 理学部, 講師 (10633290)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: 岩塩 / 沈み込み帯 / スティック・スリップ / スロー地震 / 断層ガウジ

Outline of Final Research Achievements

I conducted stick-slip experiments on halite gouges, using a large biaxial friction machine, at a range of normal stresses (10-120 MPa). with increasing normal stress, the halite gouge exhibited a transition from brittle to semi-brittle behavior. The brittle to semi-brittle transition resulted in the emergence of slow stick slip. The duration of slow slip is two orders of magnitude longer than that of normal fast slip, consistent with the difference in duration between regular and slow (e.g., tremor) earthquakes. Textural analyses also indicate that the generation of deep slow earthquakes are attributed to the heterogeneity of frictional properties on the plate interface at the semi-brittle regime.

Free Research Field

構造地質学