Climate change in the Arctic has recently become a major scientific issue, and detailed information on the degradation of subsea permafrost on continental shelves in the Arctic is critical for understanding the major cause and effects of global warming, especially the release of greenhouse gases. The subsea permafrost at shallow depths beneath the Arctic continental shelves has significantly higher P‐wave velocities than the surrounding sediments. The distribution of subsea permafrost on Arctic continental shelves has been studied since the 1970s using seismic refraction methods. With seismic refraction data, the seismic velocity and the depth of the upper boundary of subsea permafrost can be determined. However, it is difficult to identify the lower boundary and the internal shape of permafrost. Here, we present two‐dimensional P‐wave velocity models of the continental shelf in the Beaufort Sea by applying the Laplace‐domain full‐waveform inversion method to acquired multichannel seismic reflection data. With the inverted P‐wave velocity model, we identify anomalous high seismic velocities that originated from the subsea permafrost. Information on the two‐dimensional distribution of subsea permafrost on the Arctic continental shelf area, including the upper and lower bounds of subsea permafrost, are presented. Also, the two‐dimensional P‐wave velocity model allows us to estimate the thawing pattern and the shape of subsea permafrost structures. Our proposed P‐wave velocity models were verified by comparison with the previous distribution map of subsea permafrost from seismic refraction analyses, geothermal modeling, and well‐log data.

中文翻译：

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使用拉普拉斯域全波形反演对北极海底多年冻土的P波速度结构进行成像

北极地区的气候变化最近已成为一个重大的科学问题，有关北极大陆架海底多年冻土退化的详细信息对于理解全球变暖的主要原因和影响（尤其是温室气体的释放）至关重要。北极大陆架下方浅层的海底多年冻土的P波速度明显高于周围的沉积物。自1970年代以来，已经使用地震折射方法研究了北极大陆架上的海底多年冻土分布。利用地震折射数据，可以确定海底多年冻土的地震速度和上边界深度。但是，很难确定永久冻土的下边界和内部形状。这里，通过将拉普拉斯域全波形反演方法应用于采集的多通道地震反射数据，我们提出了波弗特海大陆架的二维P波速度模型。利用倒P波速度模型，我们可以确定源自海底多年冻土层的异常高地震速度。介绍了北极大陆架区域海底多年冻土的二维分布信息，包括海底多年冻土的上下边界。同样，二维P波速度模型使我们能够估计海底多年冻土结构的融化模式和形状。我们通过地震折射分析，地热模拟和测井资料与以前的海底多年冻土分布图进行了比较，从而验证了我们提出的P波速度模型。