Block modeling of crustal deformation in Tierra del Fuego from GNSS velocities
Block modeling of crustal deformation in Tierra del Fuego from GNSS velocities
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DOI：
10.1016/j.tecto.2015.03.013
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发表时间：
2015-05
期刊：
影响因子：
2.9
通讯作者：
L. Mendoza;A. Richter;M. Fritsche;J. Hormaechea;R. Perdomo;R. Dietrich
中科院分区：
文献类型：
--
作者：
L. Mendoza;A. Richter;M. Fritsche;J. Hormaechea;R. Perdomo;R. Dietrich
火地岛（TDF）主岛被南美洲和斯科舍构造板块之间的主要转换边界所分割。利用块体模型，我们根据全球导航卫星系统观测数据反演的站点速度推断出TDF活动断层的滑动速率、锁定深度和倾角。我们使用了48个地点的震间速度，这些速度是通过20年的现场测量获得的。对每个区块进行了与简单地震周期一致的欧拉矢量估计。此外，通过对主要构造板块欧拉向量的约束，将远场信息引入到模型中。在正演模型中考虑有限倾角，减小了模型与观测到的Magallanes Fagnano断裂系统（MFS）附近地表变形的差异。对于这一构造边界，全球板块回路模型预测相对运动在7 ~ 9 mm yr - 1之间，而我们的区域模型表明，整个MFS的走滑速率为5.9±0.2 mm yr - 1。我们的结果表明，断层向南倾斜66−4+ 6°，锁定在11−5+ 5km的深度，这与MFS的地质模型一致。然而，在整个MFS东部，正滑也主导着断层垂直运动，沿Fagnano湖的速度最大。
The Tierra del Fuego (TDF) main island is divided by a major transform boundary between the South America and Scotia tectonic plates. Using a block model, we infer slip rates, locking depths and inclinations of active faults in TDF from inversion of site velocities derived from Global Navigation Satellite System observations. We use interseismic velocities from 48 sites, obtained from field measurements spanning 20 years. Euler vectors consistent with a simple seismic cycle are estimated for each block. In addition, we introduce far-field information into the modeling by applying constraints on Euler vectors of major tectonic plates. The difference between model and observed surface deformation near the Magallanes Fagnano Fault System (MFS) is reduced by considering finite dip in the forward model. For this tectonic boundary global plate circuits models predict relative movements between 7 and 9 mm yr− 1, while our regional model indicates that a strike-slip rate of 5.9 ± 0.2 mm yr− 1is accommodated across the MFS. Our results indicate faults dipping 66− 4+ 6°southward, locked to a depth of 11− 5+ 5km, which are consistent with geological models for the MFS. However, normal slip also dominates the fault perpendicular motion throughout the eastern MFS, with a maximum rate along the Fagnano Lake.