Since explosive and impulsive seismic sources such as dynamite, air guns, gas guns or even vibroseis can have a big impact on the environment, some companies have decided to record ambient seismic noise and use it to estimate the physical properties of the subsurface. Big challenges arise when the aim is extracting body waves from recorded passive signals, especially in the presence of strong surface waves. In passive seismic signals, such body waves are usually weak in comparison to surface waves that are much more prominent. To understand the characteristics of passive signals and the effect of natural source locations, three simple synthetic models were created. To extract body waves from simulated passive signals we propose and test a Radon-correlation method. This is a time-spatial correlation of amplitudes with a train of time-shifted Dirac delta functions through different hyperbolic paths. It is tested on a two-layer horizontal model, a three-layer model that includes a dipping layer (with and without lateral heterogeneity) and also on synthetic Marmousi model data sets. Synthetic tests show that the introduced method is able to reconstruct reflection events at the correct time-offset positions that are hidden in results obtained by the general cross-correlation method. Also, a depth migrated section shows a good match between imaged horizons and the true model. It is possible to generate off-end virtual gathers by applying the method to a linear array of receivers and to construct a velocity model by semblance velocity analysis of individually extracted gathers.

中文翻译：

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使用氡相关从被动地震数据中反演反射波至

由于炸药、气枪、气枪甚至震源等爆炸性和冲击性地震源会对环境产生重大影响，因此一些公司决定记录环境地震噪声并用它来估计地下的物理特性。当目标是从记录的无源信号中提取体波时，尤其是在存在强表面波的情况下，就会出现巨大的挑战。在被动地震信号中，与更为突出的表面波相比，这种体波通常较弱。为了了解无源信号的特征和自然源位置的影响，创建了三个简单的合成模型。为了从模拟的被动信号中提取体波，我们提出并测试了氡相关方法。这是幅度与通过不同双曲线路径的一系列时移狄拉克三角函数的时空相关性。它在两层水平模型、包括倾斜层（有和没有横向异质性）的三层模型以及合成 Marmousi 模型数据集上进行了测试。综合测试表明，所引入的方法能够在正确的时间偏移位置重建反射事件，这些位置隐藏在通过一般互相关方法获得的结果中。此外，深度偏移剖面显示成像层位与真实模型之间的良好匹配。可以通过将该方法应用于线性接收器阵列来生成偏离端的虚拟道集，并通过对单独提取的道集进行相似速度分析来构建速度模型。