Shear-wave Velocity Structure around Teide Volcano: Results Using Microtremors with the SPAC Method and Implications for Interpretation of Geodetic Results
Shear-wave Velocity Structure around Teide Volcano: Results Using Microtremors with the SPAC Method and Implications for Interpretation of Geodetic Results
复制标题
泰德火山周围的剪切波速度结构：使用 SPAC 方法的微震结果及其对大地测量结果解释的启示
DOI：
10.1007/s00024-007-0184-9
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发表时间：
2007
影响因子：
2
通讯作者：
José Fernández
中科院分区：
文献类型：
--
作者：
F. Chávez;F. Luzón;D. Raptakis;José Fernández
火山建筑物的变形分析和模拟需要建立这些结构的弹性特性模型。本文分析了1994年在泰德火山口东部安装的两个临时地震阵列的性能测试中记录的微震测量结果。我们利用SPAC方法的最新发展，并使用空间互相关计算来估计阵列位置的瑞利波相速度色散。我们证明了标准SPAC方法的扩展在我们的数据中是有效的，证明了它的使用，并支持SPAC方法推广到单站对。对得到的相速度色散曲线进行反演，恢复阵列位置的横波剖面。我们的结果表明，火山口的底土结构在几公里的尺度上是横向均匀的。我们以2 km/s的剪切波速度获得了约315 m的火山沉积物。这些结果是可靠的，并且是进一步模拟该火山大厦永久或短暂变形的起点，这可以用于解释不同的观测场。实际上，两种模型计算了可能的火山侵入引起的变形和重力变化；一种考虑了火山沉积物，另一种不考虑火山沉积物，在近场得到了不同的结果。
Deformation analysis and simulation of volcanic edifices require the construction of models of elastic properties of those structures. In this paper we present an analysis of microtremor measurements recorded during the performance tests of two temporary seismic arrays installed in the eastern portion of the Teide caldera in 1994. We take advantage of recent developments of the SPAC method and use spatial cross-correlation computations to estimate phase velocity dispersion of Rayleigh waves at the location of the arrays. We show that the extension of the standard SPAC method is valid in the case of our data, justifying its use and supporting the generalization of the SPAC method to single station pairs. The phase velocity dispersion curve obtained was inverted to recover the shear-wave profile at the site of the arrays. Our results indicate that the subsoil structure of the caldera is laterally homogeneous at the scale of a few km about the location of the arrays. We obtained about 315 m of volcanic sediments overlying rocks with a shear-wave velocity of 2 km/s. These results are robust and are a starting point to further modelling of deformation, permanent or transient, at this volcanic edifice, which can be useful in the interpretation of different observed fields. In fact, the computation of deformations and gravity changes due to possible volcanic intrusions in two models; one considering the volcanic sediments and the other without considering them, provided different results in the near field.