[S-SS15] 地震発生の物理・断層のレオロジー

[SSS15-P13] 石英・滑石混合ガウジの摩擦特性から検証するスロースティック・スリップの発生メカニズム

*日比 涼多¹、白髭 里彩子¹、平内 健一¹、竹村 貴人² (1.静岡大学理学部地球科学科、2.日本大学文理学部地球科学科)

キーワード：層状珪酸塩鉱物、スロースティック・スリップ、速度状態依存摩擦則、スティッフネス、摩擦すべり実験、摩擦係数

In order to understand effects of phyllosilicate content on stick-slip behavior of fault zones, we conduct frictional sliding experiments on mixed quartz/talc gouges, using a direct shear apparatus. The experiments are carried out at room temperature, a normal stress of 10 MPa, and sliding velocities of 0.66–2.00 μm/s. Values of the steady-state friction coefficient and (a−b) for the quartz/talc gouges decrease with increasing talc content from 0.69 to 0.18 and from 0.0039 to −0.0032, respectively. For the gouges with talc contents of 0–8 wt.%, fast or slow stick slips occur. In slow stick-slip events, duration increases with increasing slip distance (up to 76.8 s), while stress drop decreases with increasing duration (down to 0.0046 MPa). The ratio K = k/k_c, where k is the elastic loading stiffness and k_c is the critical rheologic stiffness, slightly increases from 3.88 to 19.76 with increasing talc content. The range of K values (5.81–15.74) obtained for slow stick-slip events is above theoretically estimated K values of ~1 producing them.