To understand steeply dipping events in seismic reflection interferometry (SRI), we derived an expression that describes the difference in travel time (Δ τ ) from a diffractor to two receivers in two dimensions. For a fixed receiver interval, the expression shows that Δ τ is zero when the diffractor is at the midpoint of the paired receivers, increases with an apparent velocity of half the medium velocity as the diffractor moves toward either receiver, and remains constant for a diffractor located on the same side of both receivers. The horizontal portion of Δ τ is slightly skewed during the normal moveout correction, yielding a maximum peak of the horizontally stacked trace at a slightly smaller time than Δ τ . Accordingly, the diffracted waves have an apparent velocity slightly higher than half of the medium velocity in a horizontally stacked image. This conformed to virtual data for an elastic two-layer model with a vertical boundary. We then generalized the expression to three dimensions, in which listric travel time curves were predicted for an oblique edge diffractor, a vertex diffractor offline from the receiver pair, or a buried diffractor. Based on both two- and three-dimensional analyses of the edge diffractor, we tentatively interpreted the linear and listric dipping events observed in the passive SRI image across the Korean Peninsula to have been caused by diffractors near the intersection of the profile and geologic boundaries.

中文翻译：

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边缘衍射器在地震反射干涉测量中的不利影响

为了理解地震反射干涉测量 (SRI) 中的陡倾事件，我们导出了一个表达式，该表达式描述了从衍射器到两个接收器的二维传播时间差异 (Δτ)。对于固定的接收器间隔，该表达式表明当衍射器位于配对接收器的中点时 Δ τ 为零，当衍射器向任一接收器移动时以中速一半的视速度增加，并且对于衍射器保持恒定位于两个接收器的同一侧。Δ τ 的水平部分在正常时差校正期间略微偏斜，在略小于Δ τ 的时间产生水平叠加轨迹的最大峰值。因此，在水平叠加的图像中，衍射波的表观速度略高于中等速度的一半。这符合具有垂直边界的弹性两层模型的虚拟数据。然后，我们将表达式推广到三个维度，其中为斜边缘衍射器、接收器对离线的顶点衍射器或埋藏衍射器预测了列表行进时间曲线。基于边缘衍射器的二维和三维分析，我们初步解释了在朝鲜半岛被动 SRI 图像中观察到的线性和列表倾斜事件是由剖面和地质边界相交处附近的衍射器引起的。然后，我们将表达式推广到三个维度，其中为斜边缘衍射器、接收器对离线的顶点衍射器或埋藏衍射器预测了列表行进时间曲线。基于边缘衍射器的二维和三维分析，我们初步解释了在朝鲜半岛被动 SRI 图像中观察到的线性和列表倾斜事件是由剖面和地质边界相交处附近的衍射器引起的。然后，我们将表达式推广到三个维度，其中为斜边缘衍射器、接收器对离线的顶点衍射器或埋藏衍射器预测了列表行进时间曲线。基于边缘衍射器的二维和三维分析，我们初步解释了在朝鲜半岛被动 SRI 图像中观察到的线性和列表倾斜事件是由剖面和地质边界相交处附近的衍射器引起的。