Structural development of an accretionary prism by thrust and strike-slip faulting: Shumagin region, Aleutian Trench
Structural development of an accretionary prism by thrust and strike-slip faulting: Shumagin region, Aleutian Trench
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由逆冲和走滑断层引起的增生棱柱的构造发育：阿留申海沟舒马金地区
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发表时间：
1988
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影响因子：
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通讯作者：
T. R. Bruns
中科院分区：
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作者：
S. D. Lewis;J. Ladd;T. R. Bruns
SEABEAM条带测深数据、密集的单道地震反射剖面图和舒马金群岛区域的多道地震反射剖面图的综合结果表明，阿留申海沟这一部分的增生棱柱体的大规模变形是通过几个阶段逐步发生的：（1）在该区域内沿垂直于板块会聚方向的轴线沿着折叠，（2）板块汇聚方向的逆冲断层;（3）沿沿着共轭的西-北西向右旋和北北东向左旋断层的斜向走滑断层。走滑断层出现在不同的区域，在161°W处的一个主要横向断层以西存在右旋斜断层。161°W以东为左旋斜断层。现代阿留申海沟弧前在这一地区的结构发展可能是受前始新世继承的结构，仍然活跃在今天的应力状态。一条主要的区域边界断层位于161°W。可能是走滑断层系统的一部分，该断层系统也将Sanak盆地进一步限制在Shumagin大陆架上。该断裂带与Shumagin地震空区西部边缘的测绘位置几乎一致。这些横向结构在Shumagin前弧可能影响的空间分布的应力积累有关的俯冲，因此，大板间地震破裂带的位置，沿着这段阿留申海沟。
A combination of SEABEAM swath bathymetric data, closely spaced single-channel seismic reflection profiles, and multichannel seismic reflection profiles from the Shumagin Islands region indicates that the large-scale deformation of the accretionary prism in this segment of the Aleutian Trench occurs progressively through several stages: (1) folding along axes perpendicular to the plate-convergence direction in the region, (2) thrust faulting in the direction of plate convergence and (3) oblique strike-slip faulting along conjugate west-northwest-trending right-lateral and north-northeast-trending left-lateral faults. Strike-slip faults occur in distinct domains, with right-lateral oblique faults present west of a major transverse fault at long 161°W. and left-lateral oblique faults prevalent east of 161°W. The structural development of the modern Aleutian Trench fore arc in this region is probably affected by pre-Eocene inherited structures that are still active in the present-day stress regime. A major domain boundary fault located at long 161°W. is probably part of a strike-slip fault system that also bounds Sanak Basin farther landward on the Shumagin shelf. This fault zone is nearly coincident with the mapped position of the western edge of the Shumagin seismic gap. These transverse structures in the Shumagin fore arc probably influence the spatial distribution of stress buildup related to subduction, and hence the locations of rupture zones of great interplate earthquakes, along this segment of the Aleutian Trench.