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西雅图大都市地区的多重地震威胁被大规模树木死亡率所揭示
Bryan A Black1, Jessie K Pearl2, Charlotte L Pearson1
1Laboratory of Tree Ring Research, University of Arizona, Tucson, AZ 85701, USA.
Science advances
|September 27, 2023
概括
华盛顿州西雅图附近的复合地震发生在公元923-924年之间. 这种关联的断层事件,可能是一次7.8级地震或两次较小的地震,影响了地震危险模型.
科学领域:
- 古代地震学 (paleoseismology) 是一种古地震学.
- 地质物理学 地质物理学
- 地震科学 地震科学 地震科学
背景情况:
- 在多个断层上发生的复合地震可以表明一个地区的最大强度潜力.
- 由于记录历史中此类事件的罕见性,理解链接故障是具有挑战性的.
- 地质记录提供了长期的洞察力,但对于多断层断裂,往往缺乏精确的时间解析.
研究的目的:
- 通过古地震数据,精确地确定与故障事件相关的日期.
- 为了确定多个断层是否同时或相继破裂.
- 评估这些发现对普吉特湾地区地震危险评估的影响.
主要方法:
- 地震杀死的树木的登德罗年代测算.
- 对宇宙辐射脉冲的分析.
- 约束性树木死亡可以追溯到公元923-924年之间的6个月窗口.
主要成果:
- 关于华盛顿州西雅图附近连接断层破裂的确证据.
- 预计单次地震的地震强度为7.8级,单次地震的地震强度为7.5级,双重地震的地震强度为7.3级.
- 这一事件发生在公元923-924年的生长季节.
结论:
- 这些发现证明了相关的断层破裂,挑战了现有的地震危险模型.
- 这些场景需要对普吉特湾地区的最大地震强度进行上升的修订.
- 加强地震准备和工程设计对于受影响地区的400多万居民至关重要.
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