Great earthquakes of variable magnitude at the Cascadia subduction zone
Great earthquakes of variable magnitude at the Cascadia subduction zone
复制标题
卡斯卡迪亚俯冲带发生不同震级的大地震
DOI：
10.1016/j.yqres.2006.02.009
复制
发表时间：
2005
影响因子：
2.3
通讯作者：
R. Witter
中科院分区：
文献类型：
--
作者：
A. Nelson;H. Kelsey;R. Witter
在8个沿海地点的大地震和伴随的海啸的历史比较表明不同长度的板块边界破裂，这意味着在卡斯卡迪亚俯冲带的可变规模的大地震。破裂长度的推断依赖于地震和海啸放射性碳年龄范围的重叠程度，以及同震沉降和海啸高度的相对量。日本海啸的书面记录为1700年1月26日地震期间大部分板块边界破裂提供了最确凿的证据。卡斯卡迪亚的地层证据可以追溯到大约1600 cal yr B. P.，类似于1700年的地震，意味着类似的长期破裂，伴随着大量的沉降和高海啸。相关性与其他约1350 cal yr B. P.的长期破裂一致，2500卡/年血压，3400卡/年血压，3800卡/年血压，4400卡/年血压，700-1100 cal yr B. P.左右的破裂仅限于俯冲带的北方和中部，而北方2900 cal yr B. P.左右的破裂也可能同样受到限制。卡斯卡迪亚南部可能的短期破裂时间包括大约1100 cal yr B. P.，1700卡/年血压，3200卡/年血压，4200卡/年血压，4600卡/年血压，破裂模式表明，在最大的地震期间，北方卡斯卡迪亚的板块边界通常以长破裂的形式破裂。最南端卡斯卡迪亚的破裂长度和复发间隔比北方卡斯卡迪亚的破裂更长。
Comparison of histories of great earthquakes and accompanying tsunamis at eight coastal sites suggests plate-boundary ruptures of varying length, implying great earthquakes of variable magnitude at the Cascadia subduction zone. Inference of rupture length relies on degree of overlap on radiocarbon age ranges for earthquakes and tsunamis, and relative amounts of coseismic subsidence and heights of tsunamis. Written records of a tsunami in Japan provide the most conclusive evidence for rupture of much of the plate boundary during the earthquake of 26 January 1700. Cascadia stratigraphic evidence dating from about 1600 cal yr B.P., similar to that for the 1700 earthquake, implies a similarly long rupture with substantial subsidence and a high tsunami. Correlations are consistent with other long ruptures about 1350 cal yr B.P., 2500 cal yr B.P., 3400 cal yr B.P., 3800 cal yr B.P., 4400 cal yr B.P., and 4900 cal yr B.P. A rupture about 700–1100 cal yr B.P. was limited to the northern and central parts of the subduction zone, and a northern rupture about 2900 cal yr B.P. may have been similarly limited. Times of probable short ruptures in southern Cascadia include about 1100 cal yr B.P., 1700 cal yr B.P., 3200 cal yr B.P., 4200 cal yr B.P., 4600 cal yr B.P., and 4700 cal yr B.P. Rupture patterns suggest that the plate boundary in northern Cascadia usually breaks in long ruptures during the greatest earthquakes. Ruptures in southernmost Cascadia vary in length and recurrence intervals more than ruptures in northern Cascadia.