Wrangell Benioff zone, southern Alaska
Wrangell Benioff zone, southern Alaska
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阿拉斯加南部兰格尔贝尼奥夫地区
DOI：
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发表时间：
1984
期刊：
影响因子：
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通讯作者：
Robert A. Page
中科院分区：
文献类型：
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作者：
C. Stephens;K. Fogleman;J. Lahr;Robert A. Page
贝尼奥夫带可能与第四纪兰格尔火山有关，其存在的第一个明确证据来自一组86个位置良好的震源，这些震源发生在北纬61 °至62.5°之间和西经142 °至145.5°之间的地区，地震震级小于4级。大约有一半的地震发生在25公里或更深的地方，在40公里以下，有一个明显的北-东北倾斜的地震活动带，这里称为“兰格尔贝尼奥夫带”，延伸到大约85公里的深度，并沿着沿着走向延伸大约115公里，与火山走向近似平行。该带的西端可能与活跃得多的阿留申贝尼奥夫带的北方端偏移。在贝尼奥夫带变浅到30至40公里的地方，它几乎变成水平的，无法与上板块的地震活动明确区分开来。目前还不确定包含兰格尔贝尼奥夫带的俯冲板块段在结构上是太平洋板块还是雅库塔特板块的一部分。
The first unequivocal evidence for the existence of a Benioff zone that may be related to the Quaternary Wrangell volcanoes comes from a set of 86 well-located hypocenters for earthquakes smaller than about magnitude 4 in the region between lat 61 and 62.5°N and between long 142 and 145.5°W. About half of the earthquakes occur at depths of 25 km or less. Below 40 km a clearly defined north-northeast–dipping zone of seismicity, here termed the “Wrangell Benioff zone,” extends to a depth of about 85 km and continues for about 115 km along strike, subparallel to the volcanic trend. The western end of the zone may be offset from the northern end of the much more active Aleutian Benioff zone. Where the Benioff zone shoals to 30 to 40 km, it becomes nearly horizontal and cannot be clearly distinguished from upper-plate seismicity. It is uncertain whether the subducted plate segment that contains the Wrangell Benioff zone is structurally part of the Pacific plate or the Yakutat block.