地震研究

以断层下盘左端点为旋转基点,定义断层扭张(W1)、扭转(W2)、扭翘(W3)3种旋转模式,将其与断层走滑(U1)、倾滑(U2)、张裂(U3)3种平移模式相结合共同描述断层在空间中的运动。利用三维角点法计算直立断层平移和旋转在不同组合模式下引起的地表同震重力变化。结果表明:断层在单一转动模式下产生的重力变化分布以断层为轴线对称分布,断层在同一转动模式与不同平移模式组合的重力变化的响应程度不同。当断层处于W1转动模式时,与U2平移组合模式引起的重力变化最为显著; 当断层处于W2转动模式时,与U3平移组合模式的重力变化最为显著; 而断层在转动W3模式时,与U3平移组合模式的重力变化分布形态由U3模式向外扩张运动原因所致。断层在混合转动与混合平动组合运动模式下引起的地表重力变化分布,其主体分布与混合转动模式的分布一致,同时呈现出混合平动模式的响应。

In this paper,three rotation modes of fault twist(W1),torsion(W2),and warp(W3)are defined by the rotation basis of the left end point of the footwall,and with three translation modes of fault strike-slip(U1),dip-slip(U2),and extension/press(U3)together to describe the movement of faults in space.The three-dimensional corner point method is used to calculate the gravity changes caused by different combinations of translation and rotation of vertical faults.The conclusion is that the variation distribution of the gravity change field produced by the fault in the single rotation mode is symmetrically distributed along the fault axis.The response of the fault in the same rotational mode is different from that of the different translation modes.When the fault is in the W1 rotation mode,the gravity changes caused by the combination mode with U2 is most significant.When the fault is in the W2 rotation mode,the gravity changes caused by the combination mode with U3 is most significant,But in the W3 mode,the gravity distribution of the U3 translation combined mode is caused by the outward expansion of the U3 model.The distribution of the ground gravity changes caused by the combined movement mode of the mixed rotation and the mixed translation,and its distribution of the principal distribution is consistent with that of the mixed rotation mode,while exhibiting a hybrid translational mode response.

引言
1 基本理论与方法
2 直立断层转动产生的重力变化数值模拟
3 直立断层平移和旋转运动产生的重力变化
4 讨论与结论

图1 任意四面体的示意图<br/>Fig.1 Schematic representation of an arbitrary tetrahedron

图1 任意四面体的示意图
Fig.1 Schematic representation of an arbitrary tetrahedron

图2 直立断层模型描述断层转动示意图<br/>Fig.2 The disclination described by a vertical fault model

图2 直立断层模型描述断层转动示意图
Fig.2 The disclination described by a vertical fault model

图3 断层单一模式转动引起的地面重力变化(单位:10-8m/s2)<br/>Fig.3 Gravity changes caused by single rotational movement mode(unit:10-8m/s2)

图3 断层单一模式转动引起的地面重力变化(单位:10-8m/s2)
Fig.3 Gravity changes caused by single rotational movement mode(unit:10-8m/s2)

图4 断层的组合转动引起的地面重力变化(单位:10-8m/s2)<br/>Fig.4 Gravity changes caused by mixed rotational movements modes(unit:10-8m/s2)

图4 断层的组合转动引起的地面重力变化(单位:10-8m/s2)
Fig.4 Gravity changes caused by mixed rotational movements modes(unit:10-8m/s2)

图5 断层平移和运转组合模式引起的地面重力变化(单位:10-8m/s2)<br/>Fig.5 Gravity changes caused by single rotational and mixed translational movements modes(unit:10-8m/s2)

图5 断层平移和运转组合模式引起的地面重力变化(单位:10-8m/s2)
Fig.5 Gravity changes caused by single rotational and mixed translational movements modes(unit:10-8m/s2)

图6 断层混合转动模式与混合平动模式组合引起的地面重力变化(单位:10-8m/s2)<br/>Fig.6 Gravity changes caused by mixed rotational and mixed translational movements modes(unit:10-8m/s2)

图6 断层混合转动模式与混合平动模式组合引起的地面重力变化(单位:10-8m/s2)
Fig.6 Gravity changes caused by mixed rotational and mixed translational movements modes(unit:10-8m/s2)

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备注

引言

1 基本理论与方法

2 直立断层转动产生的重力变化数值模拟

3 直立断层平移和旋转运动产生的重力变化

4 讨论与结论

期刊信息