Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy)
Radial interpolation of GPS and leveling data of ground deformation in a resurgent caldera: application to Campi Flegrei (Italy)
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DOI：
10.1007/s00190-020-01355-x
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发表时间：
2020-02-05
影响因子：
4.4
通讯作者：
Vitale, Stefano
中科院分区：
文献类型：
--
作者：
Bevilacqua, Andrea;Neri, Augusto;Vitale, Stefano
这项研究提出了一种新的方法，称为径向插值法，以相对受限的中心地带为特征的近似径向模式为特征的数据进行内插，例如在许多活跃的火山地区显示的地面变形模式。该方法能够基于空间稀疏的地面形变测量数据快速生成短期形变图，并可提供内插值的不确定性量化，为灾害评估和形变源重建奠定了基础。该方法不依赖于关于源的几何、位置和物理性质的先验假设，除了局部辐射方向图的要求，即允许多个对称中心。我们在一个合成点源实例上测试了新方法，然后，我们将该方法应用于过去39年在Campi Flegrei火山口收集的实际大地数据的选定时间间隔，包括水准测量、大地精密导线测量和全球定位系统的例子。内陆计算的水平位移图显示，最大值位于半径约2-3公里的半圆形环状区域。这个半环状地区以断层、砂岩和裂缝等中尺度结构为标志。垂直位移图描述了测得的最大垂直隆起与体积变化之间的线性关系。如果我们估计陆地GPS网捕获的增量V的比例，并用它来估计完整的增量V，那么线性关系中的乘数约为0.3×10(6)m(3)/cm。在这种情况下，线性回归对K的95%可信区间为+/-5%。最后，我们简要讨论了如何在实时测量水平位移和垂直位移的基础上，将新方法用于生成短期喷口开度图。
This study presents a new method, called the Radial Interpolation Method, to interpolate data characterized by an approximately radial pattern around a relatively constrained central zone, such as the ground deformation patterns shown in many active volcanic areas. The method enables the fast production of short-term deformation maps on the base of spatially sparse ground deformation measurements and can provide uncertainty quantification on the interpolated values, fundamental for hazard assessment purposes and deformation source reconstruction. The presented approach is not dependent on a priori assumptions about the geometry, location and physical properties of the source, except for the requirement of a locally radial pattern, i.e., allowing multiple centers of symmetry. We test the new method on a synthetic point source example, and then, we apply the method to selected time intervals of real geodetic data collected at the Campi Flegrei caldera during the last 39 years, including examples of leveling, Geodetic Precise Traversing measurements and Global Positioning System. The maps of horizontal displacement, calculated inland, show maximum values lying along a semicircular annular region with a radius of about 2-3 km in size. This semi-annular area is marked by mesoscale structures such as faults, sand dikes and fractures. The maps of vertical displacement describe a linear relation between the maximum vertical uplift measured and the volume variation. The multiplicative factor in the linear relation is about 0.3 x 10(6) m(3)/cm if we estimate the proportion of the Delta V that is captured by the GPS network onland and we use this to estimate the full Delta V. In this case, the 95% confidence interval on K because of linear regression is +/- 5%. Finally, we briefly discuss how the new method could be used for the production of short-term vent opening maps on the base of real-time geodetic measurements of the horizontal and vertical displacements.