Andersonian wrench faulting in a regional stress field during the 2010–2011 Canterbury, New Zealand, earthquake sequence
Andersonian wrench faulting in a regional stress field during the 2010–2011 Canterbury, New Zealand, earthquake sequence
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2010-2011 年新西兰坎特伯雷地震序列期间区域应力场中的安德森扳手断层
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发表时间：
2012
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通讯作者：
R. A. Crookbain
中科院分区：
文献类型：
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作者：
R. Sibson;F. Ghisetti;R. A. Crookbain
摘要最初的Mw 7. 1达菲尔德地震序列集中在新西兰南岛的基督城以西，但余震，包括一个高度破坏性的Mw 6. 3事件，最终向东延伸到整个城市的海岸。主震沿085±5°走向的近垂直断层分段破裂痕迹产生了长达5 m的右旋走滑，该断层横跨坎特伯雷平原，持续约100年。30公里，与厄立特里亚协调机制商定。然而，近场数据表明，主震是复合的，开始与反向滑动北部的表面破裂。南岛中部的应力测定表明，最大压应力σ1为水平应力，方向为115±5°。因此，主要的右旋破裂位于c处。30°至区域σ1，低位移扭断层的经典“安德森”方向。一个余震线性构造走向c。145°可能代表共轭左旋走滑构造。该应力场也与沿南阿尔卑斯山脉前锋的NNE-NE断层的主要逆滑动重新激活一致，该断层沿着南阿尔卑斯山脉前锋。主走滑断层似乎有一个低的累积位移，并可能代表一个相当新形成的故障在区域应力场，或现有的近垂直断层，恰好是最佳的摩擦复活的方向。
Abstract The initial Mw7.1 Darfield earthquake sequence was centred west of Christchurch City in the South Island of New Zealand but aftershocks, including a highly destructive Mw6.3 event, eventually extended eastwards across the city to the coast. The mainshock gave rise to right-lateral strike-slip of up to 5 m along the segmented rupture trace of a subvertical fault trending 085±5° across the Canterbury Plains for c. 30 km, in agreement with teleseismic focal mechanisms. Near-field data however suggest that the mainshock was composite, initiating with reverse-slip north of the surface rupture. Stress determinations for the central South Island show maximum compressive stress σ1 to be horizontal and oriented 115±5°. The principal dextral rupture therefore lies at c. 30° to regional σ1, the classic ‘Andersonian’ orientation for a low-displacement wrench fault. An aftershock lineament trending c. 145° possibly represents a conjugate left-lateral strike-slip structure. This stress field is also consistent with predominantly reverse-slip reactivation of NNE–NE faults along the Southern Alps range front. The main strike-slip fault appears to have a low cumulative displacement and may represent either a fairly newly formed fault in the regional stress field, or an existing subvertical fault that happens to be optimally oriented for frictional reactivation.