The 2004–2009 caldera uplift is the largest instrumentally recorded episode of unrest at Yellowstone caldera. We use GPS and Interferometric Synthetic Aperture Radar (InSAR) time series spanning 2004–2015, with a focus in the aforementioned event to understand the mechanisms of unrest. InSAR data recorded ∼25 and ∼20 cm of uplift at the Sour Creek (SCD) and Mallard Lake (MLD) resurgent domes during 2004–2009, and ∼8 cm of subsidence at the Norris Geyser Basin (NGB) during 2004–2008. The SCD/MLD uplift was followed by subsidence across the caldera floor with a maximum at MLD of ∼1.5–2.5 cm/yr, and no deformation at NGB. The best-fit source models for the 2004–2009 period are two horizontal sills at depths of ∼8.7 and 10.6 km for the caldera source and NGB, respectively, with volume changes of 0.354 and −0.121 km³, and an overpressure of ∼0.1 MPa. The InSAR and GPS time series record exponentially increasing followed by exponentially decreasing uplift between 2004 and 2009, which is indicative of magma injection into the caldera reservoir, with no need for other mechanisms of unrest. However, magma extraction from NGB to the caldera is unable to explain the subsidence coeval with the caldera uplift. Models of magma injection can also explain other episodes of caldera uplift like that in 2014–2015. Distributed sill opening models show that magma is stored across the caldera source with no clear boundary between MLD and SCD. Since the magma overpressure is orders of magnitude below the tensile strength of the encasing rock, historical episodes of unrest like these are very unlikely to trigger an eruption.

中文翻译：

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黄石火山口的偶发岩浆注入和迁移动力学：用 InSAR 和 GPS 数据重新审视 2004-2009 年的火山口隆起事件

2004-2009 年的火山口隆起是黄石火山口有仪器记录的最大的动乱事件。我们使用跨越 2004-2015 年的 GPS 和干涉合成孔径雷达 (InSAR) 时间序列，重点关注上述事件以了解动荡的机制。InSAR 数据记录了 2004-2009 年 Sour Creek (SCD) 和 Mallard Lake (MLD) 回潮穹顶约 25 cm 和约 20 cm 的隆起，以及 2004-2008 年 Norris Geyser Basin (NGB) 约 8 cm 的沉降。SCD/MLD 隆起之后是穿过火山口底部的下沉，MLD 的最大值约为 1.5-2.5 cm/yr，NGB 没有变形。2004-2009 年期间最适合的源模型是火山口源和 NGB 深度分别为~8.7 和 10.6 公里的两个水平地基，体积变化分别为 0.354 和 -0.121 公里³和 0.1 MPa 的超压。InSAR 和 GPS 时间序列记录在 2004 年和 2009 年之间呈指数增长，然后呈指数下降，这表明岩浆注入火山口储层，不需要其他动荡机制。然而，从 NGB 到火山口的岩浆提取无法解释与火山口隆起同时期的沉降。岩浆注入模型还可以解释 2014 年至 2015 年的其他火山口隆起事件。分布的窗台开口模型表明，岩浆存储在火山口源上，MLD 和 SCD 之间没有明确的边界。由于岩浆超压比包裹岩石的抗拉强度低几个数量级，历史上像这样的动荡事件不太可能引发火山喷发。