A Review of Geological Evidence for Recurrence Times of Large Earthquakes
A Review of Geological Evidence for Recurrence Times of Large Earthquakes
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DOI：
10.1029/me004p0181
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发表时间：
2013-03
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影响因子：
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通讯作者：
K. Sieh
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文献类型：
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作者：
K. Sieh
过去几千年的地质记录包含了评估地球主要断层系统地震潜力的宝贵信息。地质学家已经开始通过研究 1）隆起的海洋阶地，2）断层陡坡形态，3）沿断层偏移的地貌特征，以及 4）断层或其他变形的年轻沉积物来表征活动断层的过去和未来的行为以及大地震的复发间隔。例如，沿着阿拉斯加和日本的汇聚板块边缘，对隆起海洋阶地的研究有助于评估两个地震间隙中断层即将破裂的可能性。在内华达州、犹他州和加利福尼亚州东部，对盆地和山脉省正断层沿线的陡坡形态的详细研究开始揭示史前地震的复发间隔、规模和模式。对沿圣安德烈亚斯断层的偏移河道的研究表明，长达10 m的右旋事件在过去曾多次发生，平均频率约为200年。在沿着圣安德烈亚斯河的其他地方以及加利福尼亚州和日本的其他断层上，对断层和变形的年轻沉积物的研究使得能够确定特定史前地震的年代，或者至少确定地层沉积期间发生的最小事件数量。在美国西部和日本，或许还有其他地震活跃地区，我们有充分的理由相信，在十年内，我们将了解多个地点过去大型地震事件的平均复发间隔、规律性和规模。希望这将能够预测未来一些具有几十年而不是几个世纪的不确定性的大地震，并为减轻灾害和指导短期预测工作到那些面临即将破裂危险的断层段提供坚实的基础。
The geological record of the past several thousand years contains valuable information for evaluating the earthquake potential of the earth's major fault systems. Geologists have begun to characterize past and, presumably, future behavior of active faults and recurrence intervals for large earthquakes by studying 1) uplifted marine terraces, 2) fault‐scarp morphology, 3) physiographic features offset along faults, and 4) faulted or otherwise deformed young sediments. Along the convergent plate margins of Alaska and Japan, for example, studies of uplifted marine terraces have aided in evaluating the likelihood of imminent rupture of faults in two seismic gaps. In Nevada, Utah, and eastern California, detailed studies of scarp morphology along normal faults of the Basin and Range Province are beginning to reveal the recurrence intervals, sizes, and patterns of prehistoric earthquakes. Studies of offset stream channels along the San Andreas fault have shown that right‐lateral events of as much as 10 m have occurred repeatedly in the past with an average frequency of about two hundred years. Elsewhere along the San Andreas and on other faults in California and Japan, studies of faulted and deformed young sediments have enabled dating of specific prehistoric earthquakes or, at least, a determination of the minimum number of events that occurred during the deposition of the strata. In the western U.S. and Japan and perhaps in other seismically active regions as well, there is good reason to believe that within the decade we will know the average recurrence intervals, regularity, and sizes of past large seismic events at several localities. Hopefully, this will enable forecasts of some future large earthquakes with uncertainties measured in decades rather than centuries and will provide a sound basis for hazard mitigation and for directing short‐term predictive efforts to those fault segments in imminent danger of rupture.