Late Holocene great earthquakes in the eastern part of the Aleutian megathrust
Late Holocene great earthquakes in the eastern part of the Aleutian megathrust
复制标题
阿留申巨型逆冲断层东部发生全新世晚期大地震
DOI：
10.1016/j.quascirev.2013.11.010
复制
发表时间：
2014
影响因子：
4
通讯作者：
Emma P. Hocking
中科院分区：
文献类型：
--
作者：
I. Shennan;R. Bruhn;N. Barlow;K. Good;Emma P. Hocking
公元 1964 年发生的 Mw9.2 大地震可能不是过去 4000 年来该地区发生的其他特大地震的典型特征。我们提供了来自三个地点的新现场数据：库珀河三角洲、卡塔拉河下游河谷和帕菲斯劳，以提高多次大地震的古地震记录的时间和空间分辨率。同震隆起和沉降的空间模式的差异表明板块边界的科迪亚克、威廉王子湾和西雅库塔特段的不同破裂组合。最长、最全面的记录均来自威廉王子湾部分。这里的大多数地点都显示出多个地震周期的净沉降，但可能的上板块断层活动在局部造成净隆起的情况除外，相距仅几公里的地点之间存在可测量的差异。我们将卡塔拉地区确定为当地地震灾害的来源，类似于雅库塔特微板块西部的其他位置，包括公元 1899 年的两次 Mw8+ 破裂。我们使用贝叶斯放射性碳建模方法来估计巨型逆冲断层威廉王子湾段的多次大地震的年龄和复发间隔。倒数第二次地震与公元 1964 年之间的间隔很长，为 883 ± 34 (2σ) 年，而较早的地震的间隔范围为 ∼420 到 ∼610 年，平均为 ∼535 年。
The great earthquake, Mw9.2, of AD 1964 may not be typical of other megathrust earthquakes in the region during the last 4000 years. We present new field data from three sites: Copper River Delta, the lower Katalla River valley and Puffy Slough, to enhance the temporal and spatial resolutions of the paleoseismic records of multiple great earthquakes. Differences in the spatial patterns of coseismic uplift and subsidence suggest different rupture combinations of the Kodiak, Prince William Sound and western Yakutat segments of the plate boundary. The longest and most comprehensive records all come from the Prince William Sound segment. Most sites here reveal net subsidence over multiple earthquake cycles except where probable upper plate faulting contributes locally to net uplift, with measurable differences between sites only a few kilometres apart. We identify the Katalla area as a source of local seismic hazard, similar to other locations in the western part of the Yakutat microplate, including the two Mw8+ ruptures in AD 1899. We use a Bayesian radiocarbon modelling approach to estimate the age and recurrence intervals of multiple great earthquakes for the Prince William Sound segment of the megathrust. The long interval, 883 ± 34 (2σ) years, between the penultimate earthquake and AD 1964 contrasts with the older earthquakes that have intervals ranging from ∼420 to ∼610 years, with a mean of ∼535 years.