A new method to identify the source vent location of tephra fall deposits: development, testing, and application to key Quaternary eruptions of Western North America
A new method to identify the source vent location of tephra fall deposits: development, testing, and application to key Quaternary eruptions of Western North America
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一种识别火山灰沉积物源喷口位置的新方法：开发、测试和在北美西部第四纪关键喷发中的应用
DOI：
10.1007/s00445-019-1310-0
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发表时间：
2019
影响因子：
3.5
通讯作者：
Pitman, E. Bruce
中科院分区：
文献类型：
--
作者：
Yang, Qingyuan;Bursik, Marcus;Pitman, E. Bruce
本文提出了一种基于碎屑厚度或最大碎屑尺寸测量来确定火山碎屑堆积物源喷口位置的新方法。它耦合一阶梯度下降法与火山灰厚度分布的两个常用的半经验模型之一。该方法被应用到三个火山灰厚度和一个最大碎屑大小数据集的北莫诺和福戈A火山灰矿床。这些数据集的随机选择和本地化的子集被用作输入，以评估其性能。结果表明，该方法的实用性，并表明，估计的扩散轴是一个更强大的方式来约束通风口的位置相比，直接估计通风口坐标稀疏观测。在局部观测的情况下，可以检测到扩散方向的局部变化。该方法采用Bootstrap聚合和可视化代价函数曲面的方法来分析认知不确定性。我们的讨论集中在火山灰沉积物的不同特征和方法的技术方面将如何影响方法的性能。给出了在有限观测条件下如何使用该方法的建议。北单床1厚度数据集和Trego温泉和罗克兰tephras的厚度数据集的一个子集被用作案例研究。然后，该方法被应用到威尔逊溪地层内的相关火山灰子单元，以估计其喷口的位置和体积。该方法的简单性和灵活性使其成为分析火山灰瀑布沉积物的潜在有用工具。
A new method to identify the source vent location of tephra fall deposits based on thickness or maximum clast size measurements is presented in this work. It couples a first-order gradient descent method with either one of two commonly used semi-empirical models of tephra thickness distribution. The method is applied to three tephra thickness and one maximum clast size datasets of the North Mono and Fogo A tephra deposits. Randomly selected and localized subsets of these datasets are used as input to evaluate its performance. The results suggest the utility of the method and show that estimating the dispersal axis is a more robust way to constrain the vent location compared with directly estimating the vent coordinates given sparse observations. Local change in dispersal direction can be detected given localized observations. Bootstrap aggregating and visualizing the surface of the cost function are used to analyze epistemic uncertainty for the method. Our discussion focuses on how different features of tephra deposits and technical aspects of the method would affect the performance of the method. Suggestions on how to use the method given limited observations are listed. One subset of the North Mono Bed 1 thickness dataset and thickness datasets of the Trego Hot Springs and Rockland tephras are used as case studies. The method is then applied to the well-correlated tephra sub-units within the Wilson Creek Formation to estimate their vent location and volume. The simplicity and flexibility of the method make it a potentially useful tool for analyzing tephra fall deposits.
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影响因子：
2.3
作者：
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DOI：
--
发表时间：
1997
期刊：
The Journal of geology
影响因子：
--
作者：
C. Wilson;W. Hildreth
通讯作者：
W. Hildreth
影响因子：
2.7
作者：
G. Walker;R. Croasdale
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G. Walker;R. Croasdale
影响因子：
3.5
作者：
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通讯作者：
R. Sparks;S. Carey;H. Sigurdsson
影响因子：
3.5
作者：
Engwell, S. L.;Aspinall, W. P.;Sparks, R. S. J.
通讯作者：
Sparks, R. S. J.