【摘要】 为了准确模拟任意主频情况下的初至走时和照明,应用高阶交错网格有限差分法进行了时域双程波动方程正演数值模拟,拾取最大振幅能量节点位置对应的旅行时间作为初至走时。以均匀介质为例,对比研究了本文方法与解析走时和高频近似走时(基于程函方程)在不同主频情况下的双程走时结果,指出在主频较高时三者最为接近。以Marmousi模型为例,计算了不同主频对应的初至走时及其振幅能量。综合分析表明,低主频存在较大的旅行时计算误差,不同的主频可以照明不同尺度的介质变化,从而指导实际地震资料的数字处理。更多还原

【Abstract】 In order to correctly determine the first arrivals and the illumination for arbitrary dominant frequency,we performed forward numerical simulation on time domain two way wave equation using high-order staggered grid finite difference scheme,and took the traveltime corresponding to the maximum amplitude energy as the first arrival time.We compared the two way traveltimes resulted from the proposed method,the analytic method,and the high frequency approximation method which is based on eikonal equation on isotropic medium for different dominant frequency,and concluded that the three methods yield similar results in high dominant frequency.On Marmousi model,we calculated first arrivals and illuminations for different dominant frequency.Large error of travel time occurs at low dominant frequency,and illumination varies with dominant frequency.更多还原