Deformation rates estimated from earthquakes in the northern Cordillera of Canada and eastern Alaska
Deformation rates estimated from earthquakes in the northern Cordillera of Canada and eastern Alaska
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根据加拿大北部科迪勒拉山脉和阿拉斯加东部地震估算的变形率
DOI：
10.1029/2007jb005456
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发表时间：
2008
影响因子：
--
通讯作者：
R. Hyndman
中科院分区：
文献类型：
--
作者：
L. Leonard;S. Mazzotti;R. Hyndman
[1]我们估计变形率从地震目录统计调查目前的应变分布所造成的雅库特块与北美的碰撞。碰撞是在阿拉斯加和加拿大西北部的广泛地区，在各种构造制度。我们的估计有显着的不确定性，但结果一般与其他变形率估计（GPS和地质数据），并提供有用的一阶约束当地长期的构造变形和地震危险性。我们估计，50-75%的相对板块运动是由雅库特/北美边界的地震，横向地壳挤压，其他远场应变，并可能适应其余的地震蠕变。我们计算的右旋走滑4.5-10.2毫米/年的德纳里断层系统在阿拉斯加，非常相似的晚更新世/全新世速率从地貌偏移。右旋运动基本上绕过了阿拉斯加最东端和育空地区最西端的迪纳利断层，而是沿着托特顺达和杜克河断层系统。5-10 mm/a的右移挤压表明阿拉斯加前弧不具有完全的块状行为。在阿拉斯加的Denali和Tintina-Kaltag断层之间，10-20 mm/a的右旋剪切被几个NE向的“书架”断层所容纳。显着的地震变形（在高于预期的情况下，从GPS数据）表示在东北科迪勒拉，预先存在的断层有很强的控制模式和机制，目前的变形。
[1] We estimate deformation rates from earthquake catalog statistics to investigate current strain distribution resulting from the collision of the Yakutat block with North America. The collision is accommodated over a broad region of Alaska and NW Canada in a variety of tectonic regimes. Our estimates have significant uncertainties, but the results are generally in agreement with other deformation rate estimates (GPS and geological data) and provide useful first-order constraints on local long-term tectonic deformation and seismic hazard. We estimate that 50–75% of relative plate motion is taken up by earthquakes on the Yakutat/North America boundaries, with lateral crustal extrusion, other far-field strain, and possibly aseismic creep accommodating the remainder. We calculate dextral strike slip of 4.5–10.2 mm/a on the Denali fault system in Alaska, remarkably similar to late Pleistocene/Holocene rates from geomorphic offsets. Right-lateral motion essentially bypasses the Denali fault in easternmost Alaska and westernmost Yukon, passing instead along the Totschunda and Duke River fault systems. Right-lateral transpression of 5–10 mm/a suggests that the Alaskan fore arc does not have fully block-like behavior. Between the Denali and Tintina-Kaltag faults in Alaska, 10–20 mm/a of dextral shear is accommodated by several NE trending “bookshelf” faults. Significant seismic deformation (in cases higher than expected from GPS data) is indicated in the NE Cordillera, where preexisting faults have a strong control on the pattern and mechanisms of current deformation.