Time-dependent deformation of Uturuncu volcano, Bolivia, constrained by GPS and InSAR measurements and implications for source models
Time-dependent deformation of Uturuncu volcano, Bolivia, constrained by GPS and InSAR measurements and implications for source models
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玻利维亚乌图伦库火山随时间的变形，受 GPS 和 InSAR 测量的约束以及对源模型的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
M. Pritchard
中科院分区：
文献类型：
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作者：
S. Henderson;M. Pritchard
在玻利维亚乌图伦库火山山顶附近进行的新的连续GPS观测表明，2010年4月至2015年11月期间的平均抬升速率为2.4 ± 1.9毫米/年，而1992年5月至2011年1月期间的先前干涉合成孔径雷达（干涉合成孔径雷达）观测预测的平均垂直抬升速率为7 ± 2毫米/年。然而，GPS时间序列与时间相关函数更好地拟合，因此2010年的抬升速率小于2 mm/年，2015年可能高达9 mm/年。在连续的GPS时间序列中的非恒定速率的指示的动机，我们研究在何种程度上过去的干涉合成孔径雷达测量可能已经暂时混叠。我们提出的证据表明，自2004年以来，隆起的减少是允许的可用干涉合成孔径雷达，并与较低的平均GPS速率自2010年以来。我们讨论了这些可变的速率可能会影响以前提出的岩浆模型在Uturuncu，包括底辟上升和水库增压。特别是，我们探讨了一个“偶极子”水库模型，包括岩浆源在下地壳和下沉中地壳的岩浆供应的变化可以解释变形速率的次十年波动。使用均质模型反演多个干涉合成孔径雷达数据集，将较深储层限制在55-80 km深度（下地壳和上地幔），将较浅储层限制在20-35 km。与之前的工作一致，源与汇之间体积变化的推断比率（即，深：浅）储层高达10：1。我们还将新的地震层析成像的结果在三维有限元模型，探索多个源和材料的异质性对地表变形的综合影响。从我们的建模工作中得出的一个重要结论是，变形源形状的最大径向与垂直表面位移的常用诊断比受多个储层和地下非均质性的存在的影响。最后，偶极子和底辟模型有未解决的缺点，提供了整套可用的地球物理数据，但都提供了宝贵的洞察力的条件，岩浆上升在中央安第斯山脉。
New continuous GPS observations near the summit of Uturuncu volcano, Bolivia, indicate an average uplift rate of 2.4 ± 1.9 mm/yr between April 2010 and November 2015, while previous interferometric synthetic aperture radar (InSAR) observations between May 1992 and January 2011 predict an average vertical uplift rate of 7 ± 2 mm/yr. However, the GPS time series is better fit with a timedependent function, such that the uplift rate in 2010 is less than 2 mm/yr and in 2015 may be as high as 9 mm/yr. Motivated by indications of a non-constant rate in the continuous GPS time series, we examine to what extent past InSAR measurements may have been temporally aliased. We present evidence that decreased uplift since 2004 is permitted by available InSAR and is consistent with a lower average GPS rate since 2010. We discuss how these variable rates may affect previously proposed magmatic models at Uturuncu including diapir ascent and reservoir pressurization. In particular, we explore a “dipole” reservoir model consisting of a magma source in the lower crust and sink in the middle crust for which variation in magma supply could explain sub-decadal fluctuations in deformation rate. Inversion of multiple InSAR data sets using homogeneous models constrains the deeper reservoir to 55–80 km depth (lower crust and upper mantle) and the shallower reservoir to 20–35 km. Consistent with previous work, the inferred ratio of volume change between the source:sink (i.e., deep:shallow) reservoirs is up to 10:1. We also incorporate new seismic tomography results in a 3D finite-element model to explore the combined effects of multiple sources and material heterogeneity on surface deformation. An important conclusion from our modeling efforts is that the commonly used diagnostic ratio of maximum radial to vertical surface displacements for shape of the deformation source is affected by both the presence of multiple reservoirs and subsurface heterogeneity. Ultimately, the dipole and diapir models have unresolved shortcomings given the entire suite of available geophysical data, but both provide valuable insight into the conditions for magmatic ascent in the Central Andes.
影响因子：
2.8
作者：
T. Walter;M. Motagh
通讯作者：
T. Walter;M. Motagh
高原-普纳变形异常的热机械建模：岩浆糊重组的多参数见解
影响因子：
2.5
作者：
Gottsmann J
通讯作者：
Gottsmann J
影响因子：
5.2
作者：
del Potro, Rodrigo;Diez, Mikel;Gottsmann, Joachim
通讯作者：
Gottsmann, Joachim