TanDEM‐X Time Series Analysis Reveals Lava Flow Volume and Effusion Rates of the 2012–2013 Tolbachik, Kamchatka Fissure Eruption
TanDEM‐X Time Series Analysis Reveals Lava Flow Volume and Effusion Rates of the 2012–2013 Tolbachik, Kamchatka Fissure Eruption
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DOI：
10.1002/2017jb014309
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发表时间：
2017-10
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影响因子：
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通讯作者：
J. Kubanek;M. Westerhaus;B. Heck
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作者：
J. Kubanek;M. Westerhaus;B. Heck
评估喷发量是火山研究的主要挑战之一，但它提供了对喷发动力学和相关危害的宝贵见解。估计这一重要参数的一种方法是在喷发之前、期间和之后获取数字高程模型（DEM）的生成和差分。卫星使命TanDEM‐X能够使用合成孔径雷达卫星图像生成DEM的时间序列。我们使用这些数据来研究2012-2013年堪察加半岛Tolbachik的喷发。我们开发了一种处理方案，用于从TanDEM-X图像生成18个DEM，该方案依赖于用于处理同生喷发和后喷发数据对的喷发前DEM的生成。区别每个DEM与喷发前DEM，使映射的熔岩流和测量熔岩流量随时间的推移，并估计熔岩挤出速率。我们发现最终的熔岩流体积为0.53立方公里，覆盖面积为36平方公里的喷发结束。在分析预计不会发生地形变化的地区的DEM差异时，进行了不确定性分析，导致最终熔岩流量的误差为±0.01 km 3。火山喷发初期熔岩流量高达247.92 m3/s，并在喷发结束时迅速衰减。虽然许多玄武岩喷发遵循指数衰减流动模型，但托尔巴奇克的挤出率更符合1/t模型。这一特殊的特征可能有助于进一步了解托尔巴奇克的喷发过程。
Assessing eruption volumes is one of the major challenges in volcano research but provides valuable insights into the dynamics of an eruption and the associated hazard. One way to estimate this important parameter is the generation and differencing of digital elevation models (DEMs) acquired before, during, and after an eruption. The satellite mission TanDEM‐X enables generation of time series of DEMs using synthetic aperture radar satellite imagery. We use these data to study the 2012–2013 eruption of Tolbachik in Kamchatka. We developed a processing scheme for generation of 18 DEMs from TanDEM‐X imagery that relies on the generation of a preeruption DEM which is used to process the syneruption and posteruption data pairs. Differencing each DEM with the preeruption DEM enables mapping the lava flows and measuring lava flow volume over time and to estimate lava extrusion rates. We find a final lava flow volume of 0.53 km3 covering an area of 36 km2 by the end of the eruption. An uncertainty analysis is performed while analyzing the DEM differences in areas where no topographic change is expected, leading to an error of ±0.01 km3 for the final lava flow volume. The lava effusion was with 247.92 m3/s very high in the first days of the eruption and rapidly decayed toward its end. While many basaltic eruptions follow an exponentially decaying flow model, the extrusion rates at Tolbachik are more compatible with a 1/t model. This special characteristic might be useful to gain further insight into the eruption process at Tolbachik.