Oceanic transform faults (OTFs) represent an attractive tectonic environment to investigate how slip is accommodated within the crust. However, as most of these fault systems grow in the deep ocean, where few local seismic observations are available, characterizing their earthquake behavior is complicated and remains a formidable challenge. Here we present a novel approach for retrieving precise centroid locations of submarine earthquakes that is based on the modeling of water phases in teleseismic records. Using a hybrid method for simulating far‐field body waves with 3D source‐side structures, we demonstrate that the scattered energy generated by the continuous bounces of an earthquake's P‐wave trapped in the ocean is modelable and carries information about its source location. As a case study, we use a realistic bathymetry model of the Gofar transform fault on the East Pacific Rise and simulate the seismic wavefield at US Array stations for four of its moderate‐sized (Mw5.0+) earthquakes. Our modeling results show that water phases are sensitive to a ∼5 km change in the earthquake's horizontal location and that a remarkable agreement between observed and synthetic water phases is achieved when the location of an event is close to its true one. We then relocate three of these events by systematically computing their water phases in candidate locations until a satisfactory waveform fit is achieved. This analysis technique paves a new route for studying earthquake source properties in isolated marine environments and serves as a mean to investigate the seismic behavior of OTFs on a global scale.

中文翻译：

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从水混响的3D波形建模看海底地震的绝对质心位置

海洋转换断层（OTF）代表了一个有吸引力的构造环境，可研究地壳内部如何容纳滑移。但是，由于大多数断层系统生长在深海中，而当地几乎没有地震观测资料，因此表征其地震行为十分复杂，并且仍然是一个艰巨的挑战。在这里，我们提出一种基于远震记录中水相建模的海底地震精确质心位置的新颖检索方法。通过使用一种混合方法模拟具有3D源侧结构的远场体波，我们证明了被困在海洋中的地震P波的连续弹跳所产生的散射能量是可建模的，并且承载了有关其震源位置的信息。作为案例研究 我们使用东太平洋上升带Gofar变换断层的现实测深模型，并针对其中度（Mw5.0 +）地震中的四次，模拟了US Array站的地震波场。我们的模拟结果表明，水位对地震水平位置约5 km的变化敏感，并且当事件的位置接近其真实位置时，观测到的和合成的水相之间会达成显着的一致性。然后，我们通过系统地计算它们在候选位置的水相来重新定位这些事件中的三个，直到获得令人满意的波形拟合为止。这项分析技术为研究孤立海洋环境中的震源特性开辟了一条新途径，并为在全球范围内研究OTF的地震行为提供了一种手段。