Sagami Bay in central Japan is known as the seismogenic and tsunamigenic zone of the 1703 and 1923 Kanto earthquakes that caused devastating damage in the Tokyo metropolitan area. However, the tsunamigenic structure within the frontal wedges of the subduction zone remains unresolved after the last disastrous events. In the present study, the detailed structural features of the shallowest structure of the Sagami Tectonic Line in Sagami Bay were revealed by seismic reflection, a deep-towed high-resolution sub-bottom profiler, and swath bathymetry data. Based on our data, the middle segments of the Sagami Tectonic Line, which is distributed along the southwestern rim of the Miura Knoll, are considered highly likely to be an active fault that has been a repeatedly active feature. The trough-fill sediments of the south Sagami Bay are currently thought to be actively deformed by the compressive stress accompanying northwestward subduction of the tip of Izu-Ogasawara (Bonin) Arc crust on the Philippine Sea plate.

中文翻译：

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伊豆岛弧逼近引发的相模湾活动变形

日本中部的相模湾被称为 1703 年和 1923 年关东地震的发震和海啸带，这些地震对东京都造成了毁灭性的破坏。然而，在最后一次灾难性事件之后，俯冲带锋楔内的海啸结构仍未得到解决。在本研究中，通过地震反射、深拖高分辨率海底剖面仪和条带测深数据揭示了相模湾相模构造线最浅层结构的详细结构特征。根据我们的资料，沿着三浦丘西南缘分布的相模构造线的中段被认为极有可能是一个具有反复活动特征的活动断层。