复杂近地表弹性波波场特征研究

 本文采用任意起伏地表二维弹性波方程交错网格高阶有限差分法模拟，通过地震波波场快照、单炮记录以及合成的近似叠加记录，分析了不同倾角斜层模型、起伏基岩面模型以及起伏地表下简单构造模型等3个简化模型弹性波场特征、弹性波主要类型以及弹性波传播规律。模型试验结果表明，近地表斜层、起伏基岩面以及速度横向非均匀引起折射波的不连续。近地表速度结构和地形不仅引起地下反射波同相轴弯折、畸变，而且产生严重的规则干扰。

Study on feature of elastic wavefield in complex near surface

Through snap shots of seismic wavefield,single-shot records and approximately synthetic stack section,the paper used 2-D elastic wave equation staggering grid high-order finite-difference simulation on arbitrarily relief surface to analyze the feature of elastic wavefield,main type and propagation rule of elastic wave for three simplified model as inclined strata with different dips,relief surface of base rock and simple structure under relief surface.It is shown by model tests that inclined strata in near surface,relief surface of base rock and lateral non-uniformity of velocity can cause non-continuity of refractions.The near-surface velocity structure and geomorphology resulted in not only bend and distortion of events of underground reflections,but also producing severe regular interference.