断层走滑不均匀性对地面变形的影响

Effects on the earth surface deformation by asymmetric strike slip on fault plane

根据塞积群理论导出了走滑断层两端点固定时位移场随位置的不均匀分布解析表示关系,分析和讨论了断层上不同位置的位移场分布特征,采用新导出的断层滑动不均匀分布公式对地面的水平位移场和垂直位移场进行了数值模拟计算,并与传统的Okada位错模型在理论和计算结果上进行了对比分析.理论和计算结果分析表明:断层滑动不均匀分布公式是Okada位错模型在一定条件下理论上的扩展,而Okada位错模型是走滑不均匀公式的零阶近似;断层滑动不均匀分布公式与Okada位错模型计算的地面位移场在走滑方向、垂直于断层走向和垂直于地面方向的近场变形差异最大在50%至65%之间,而最小差异在1%以内.

The formula to express asymmetric strike slip on fault plane are derived by pile-up model when two ends of fault is fixed or locked. The distribution characteristics of slip along fault length are discussed and analyzed by the formula derived. At the same time, the deformation on the earth surface are computed by new derived asymmetric strike slip formula and Okada model respectively. The theory and computed results show that the formulas derived in this study is extended of Okada model, the biggest differences of near-field deformation between new derived asymmetric strike slip formula and Okada model are from 50% to 65% in fault strike slip direction, in direction normal to fault and in vertical direction. The smallest difference between asymmetric strike slip formula and Okada model is in 1%.