Seismological evidence for a tsunami earthquake recorded four centuries ago on historical documents
Seismological evidence for a tsunami earthquake recorded four centuries ago on historical documents
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DOI：
10.1093/gji/ggt270
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发表时间：
2013-11-01
影响因子：
2.8
通讯作者：
Nakamura, Mamoru
中科院分区：
文献类型：
--
作者：
Ando, Masataka;Nakamura, Mamoru
历史文献记载，南开海槽近1400年来每隔100-150年就发生一系列大地震。这些文件结合最近的地震学数据表明，最近的五次大地震是发生在菲律宾海板块上界面的巨型逆冲事件。然而，1605年的Keicho地震(M-t=8.2)与这五次地震不同：日本西海岸发生了广泛的海啸破坏，尽管由于强烈的地面运动而相对缺乏破坏。根据这些数据，这场地震被认为是一场“海啸地震”，与其地震波相比，海啸产生了不成比例的大海啸。在这项研究中，我们仔细检查了一篇日记，作者在日记中描述了41年来京都感受到的地震。详细的分析表明，作者极不可能没有在日记中记录这一事件。假设这一事件发生在海沟轴线附近的浅板界面上，根据历史文件中记录的数据进行了海啸模拟。如果1605年的地震是一次“海啸地震”，那就不能认为这是一次沿南开海槽每隔100-150年就发生在板块界面孕震带上的普通冲断事件。如果我们将这一事件排除在这一组之外，两次地震的间隔将增加到大约200-400年，这意味着大地震的发生间隔范围很大。
Historical documents reveal that a series of large earthquakes occurred in the past 1400 yr along the Nankai Trough at an interval of 100-150 yr. These documents, combined with recent seismological data, show that the five most recent large earthquakes are megathrust events that occurred on the upper interface of the Philippine Sea Plate. However, the 1605 Keicho earthquake (M-t = 8.2) differs from these five events: extensive tsunami damage occurred along the western coast of Japan, despite a relative lack of damage due to strong ground motions. Based on these data, the earthquake is thought to be a 'tsunami earthquake', which generates a disproportionally large tsunami compared to its seismic waves. In this study, we carefully examined a diary in which the writer described earthquakes felt in Kyoto over 41 yr. Detailed analysis shows that it is extremely unlikely that the writer did not record the event in the diary. Assuming that this event occurred on the shallower plate interface near the trench axis, a tsunami simulation was performed based on the data recorded in historical documents. If the 1605 earthquake is a 'tsunami earthquake', this earthquake cannot be considered an ordinary thrusting event on the seismogenic zone of the plate interface that occurs at an interval of 100-150 yr along the Nankai Trough. If we exclude this event from such a group, the interseismic interval increases to approximately 200-400 yr, which implies that large earthquakes occur with a wide range of interval.