Relaxation processes of a thick granular layer at seismic slip rates

• Project/Area Number: 25800257
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Solid earth and planetary physics
• Research Institution: Japan Agency for Marine-Earth Science and Technology
• Principal Investigator: KUWANO Osamu 国立研究開発法人海洋研究開発機構, 数理科学・先端技術研究分野, 研究員 (30511969)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000); Fiscal Year 2015: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000); Fiscal Year 2014: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000); Fiscal Year 2013: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
• Keywords: 断層 / 粉体 / 摩擦構成則 / 断層形状

Outline of Final Research Achievements

We conducted laboratory experiments designed to explore transient responses of a thick granular layer following a step change in slip velocity at seismic slip rates. Experiments were performed at constant normal stresses of 10- 30kPa using a ring shear apparatus with inner/outer diameters of 15mm/25mm. We measure the friction coefficient and thickness of glass beads layer at sliding velocities between 0.5 and 3 m/s. Experimental results show that the friction coefficient and layer thickness suddenly increases/decrease as sudden increase/decrease of sliding velocity and then exponentially decay to new steady state with characteristic slip length. We found that characteristic slip length is of the order of 10m. The response to a velocity step decreases simply symmetric to that to a velocity step increase.

Research Products

• [Presentation] Friction of granular layer at seismic slip rates - Effect of wall disturbances (2015)
  • Author(s): 桑野修・中谷正生・波多野恭弘・阪口秀
  • Organizer: 日本地球惑星科学連合2015年大会
  • Place of Presentation: 幕張メッセ、千葉県千葉市
  • Year and Date: 2015-05-27
• [Presentation] 粉体層の摩擦応答に及ぼす壁面粗さの影響 (2014)
  • Author(s): 桑野修・中谷正生・波多野恭弘・阪口秀
  • Organizer: 日本地震学会2014年度秋季大会
  • Place of Presentation: 朱鷺メッセ、新潟県新潟市
  • Year and Date: 2014-11-24
• [Presentation] 高速剪断される粉体層の緩和過程と粉体層厚 (2014)
  • Author(s): 桑野修・中谷正生・波多野恭弘・阪口秀
  • Organizer: 日本地球惑星科学連合2014年大会
  • Place of Presentation: パシフィコ横浜、神奈川県横浜市
  • Year and Date: 2014-04-30
• [Presentation] 高速剪断される厚い粉体層の緩和過程
  • Author(s): Osamu Kuwano, Masao Nakatani, Takahiro Hatano, Hide Sakaguchi
  • Organizer: 日本地球惑星科学連合2013年大会
  • Place of Presentation: 幕張メッセ,千葉県千葉市
• [Presentation] 高速すべり速度ステップ実験で観察された長いDc
  • Author(s): 桑野修・中谷正生・波多野恭弘・阪口秀
  • Organizer: 日本地震学会2013年秋季大会
  • Place of Presentation: 神奈川県民ホール,神奈川県横浜市
• [Presentation] Relaxation processes of a thick granular layer at seismic slip rates
  • Author(s): Osamu Kuwano, Masao Nakatani, Takahiro Hatano, Hide Sakaguchi
  • Organizer: 2013 AGU Fall Meeting
  • Place of Presentation: Moscone Center, San Francisco, CA, USA