We investigate a shallow lake basin for evidence of a large historic intraplate earthquake in western North America. Henrys Lake, Idaho is an atypical candidate for lacustrine paleoseismic study given its shallow depth (∼7 m) and low relief (≤2° slopes). Here, we test the earthquake-recording capacity of this basin type by showing sedimentological evidence of the 1959 M7.3 Hebgen Lake earthquake within sediment cores, using anthropogenically produced ¹³⁷Cs activity to constrain timing. In addition to expanding the morphologic range of basins targeted for lacustrine paleoseismic studies, this work has implications for sediment response in dam-enhanced basins. Lack of sedimentological evidence for other earthquakes coupled with radiocarbon chronology reveals that the 1959 event is the only clearly recorded earthquake within Henrys Lake since the mid-Holocene. Henrys Lake offers a proxy for paleo-earthquake signatures within similar lacustrine environments and underscores the importance of further paleoseismic studies in the region.

中文翻译：

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浅湖，强烈震动：1959 年爱达荷州亨利斯湖内 M7.3 赫布根湖地震地震触发的湖浆沉积记录


我们调查了一个浅湖盆地，以寻找北美西部历史上一次大型板块内地震的证据。爱达荷州亨利斯湖因其较浅的深度 （∼7 m） 和低起伏 （≤2° 的坡度） 而成为湖泊古地震研究的非典型候选者。在这里，我们通过展示 1959 年 M7.3 赫布根湖地震的沉积学证据来测试这种盆地类型的地震记录能力在沉积物岩芯内，使用人为产生的 ¹³⁷Cs 活动来限制时间。除了扩大湖泊古地震研究所针对的盆地的形态范围外，这项工作还对大坝增强盆地的沉积物响应具有影响。缺乏其他地震的沉积学证据，再加上放射性碳年代学，表明 1959 年的事件是自全新世中期以来亨利湖内唯一明确记录的地震。亨利湖为相似湖泊环境中的古地震特征提供了代理，并强调了该地区进一步古地震研究的重要性。