摘要
实验变形的含有粘土矿物断层泥的显微结构观察提供了判别自然界断层滑动习性的标志 .含有粘土矿物断层泥的摩擦实验显示了 2种模式 ,一种是稳态滑动 ,另一种是粘滑 ,即有可能发生大地震 .此两种实验产物的显微结构记录了断层的滑动性质 ,均匀变形的断层泥是断层非地震 (稳滑 )的结果 ,局部强烈变形是断层地震 (粘滑 )的产物 .均匀变形使粘土矿物产生优选方位 (S叶理 ) ,在一定程度上它反映了剪应变的大小 ,局部变形形成吕德剪切和Y剪切 ,云南小湾F7断层中具有类似的结构特征 ,计算结果表明F7的稳滑量约 43 %～ 5 2 % .
Structures observed with experimentally deformed clay gouge provide information that may be used to identify the seismic behavior of natural fault zones.In laboratory friction experiments clay gouge exhibits two modes of behavior:one can only result in stable fault creep,and the other may result in stick slip,but has the potential large earthquakes.Microstructures that form during these experiments reflect the deformation style of the clay gouge.Pervaded deformation results from aseismic fault creep,and localized deformation results from seismic slip.Pervaded deformation produces preferred orientation of the clay grain (S foliation).The orientation of the S foliation gives some information on the magnitude of bulk shear strain.Localized defromation forms Riedel and Y shears.Similar structures occur within a natural F 7 fault in Xiao Wan,Yunnan.The resulting shows stagle creep ratio about 43～52 in F 7 fault.
基金
国家自然科学基金!资助项目 (4 9772 16 8)
