Journal of Geophysical Research: Solid Earth Deformation in the Northern Volcanic Zone of Iceland 2008–2014: An interplay of tectonic, magmatic, and glacial isostatic deformation
Journal of Geophysical Research: Solid Earth Deformation in the Northern Volcanic Zone of Iceland 2008–2014: An interplay of tectonic, magmatic, and glacial isostatic deformation
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地球物理研究杂志：2008-2014 年冰岛北部火山带的固体地球变形：构造、岩浆和冰川等静压变形的相互作用
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通讯作者：
Tom Zentek
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作者：
A. Rashid;M. Müller;Tom Zentek
2008年至2014年的GPS测量用于推导冰岛北方火山区（NVZ）的表面速度场，该火山区是北美和欧亚板块之间分歧边界的陆上部分。在这段时间内，该区域没有发现火山活动或岩浆侵入。我们推断伸展速率为17.4 + 0。2比0。在292.0 + 0方向上3 mm/年。五比零这与前人的研究结果以及MORVEL 2010和GEODVEL 2010等现代板块运动模型的结果一致。水平速度场揭示了由板块分离运动引起的约50 km宽的伸展带。冰川均衡调整（GIA）导致瓦特纳冰盖北方边缘以每年20 mm以上的速度抬升，并导致每年3-4 mm的水平运动远离冰盖。2008年至2014年期间NVZ的变形可以通过与几个不同过程相关的模型组合来再现：（i）Askja和Kra Jena火山的火山和地热变形的Mogi源，（ii）来自冰川均衡模型的速度场的缩放版本，以及（iii）基于简单反正切的长期板块扩张模型。我们找到了板块边界扩张轴的大致位置及其锁定深度。扩张轴穿过克拉伊纳火山、弗雷姆里纳马尔火山和阿斯克亚火山，这些火山是NVZ中最活跃的火山。它似乎并不遵循每个裂缝群的大致方向，而是在中央火山处改变方向。锁定深度平均在7-9公里范围内。
GPS measurements spanning 2008 to 2014 are used to derive the surface velocity field across the Northern Volcanic Zone (NVZ) of Iceland, a subaerial part of the divergent boundary between the North American and Eurasian plates. No volcanic activity nor magmatic intrusions were detected in the zone during this time period. We infer an extensional rate of 17.4 + 0 . 2 − 0 . 3 mm/yr in direction 292.0 + 0 . 5 − 0 . 6 ∘ , consistent with the results of previous studies and current plate motion models including MORVEL2010 and GEODVEL2010. The horizontal velocity field reveals about 50 km wide stretching zone caused by the divergent plate movements. Glacial isostatic adjustment (GIA) induces uplift of over 20 mm/yr at the northern edge of Vatnajökull ice cap and 3–4 mm/yr horizontal motion directed away from the ice cap. Deformation in the NVZ between 2008 and 2014 can be reproduced by a combination of models relating to several different processes: (i) Mogi sources for volcanic and geothermal deformation at the Askja and Krafla volcanoes, (ii) scaled version of a velocity field derived from a glacial isostatic model, and (iii) simple arctangent-based model for secular plate spreading. We find the approximate location of the plate boundary spreading axis as well as its locking depth. The spreading axis lies through the Krafla, Fremrinámar, and Askja central volcanoes, the most active ones in the NVZ. It does not appear to follow the general direction of each fissure swarm but rather to change direction at the central volcanoes. The locking depth is on average within the 7–9 km range.