Analysis and Modeling of hvsr in the Presence of a Velocity Inversion: The Case of Venosa, Italy
Analysis and Modeling of hvsr in the Presence of a Velocity Inversion: The Case of Venosa, Italy
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存在速度反演时的 hvsr 分析和建模：以意大利韦诺萨为例
DOI：
10.1785/0120040242
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发表时间：
2005
影响因子：
3
通讯作者：
S. Richwalski
中科院分区：
文献类型：
--
作者：
D. Giacomo;M. Gallipoli;M. Mucciarelli;S. Parolai;S. Richwalski
这项工作的目的是检查在Venosa站（意大利）计算的水平-垂直光谱比的稳定性。该场地位于地震基岩上方的一层人为填土（4 m厚）、一层坚硬的砾岩（15 m厚）和一层厚粘土（约300 m厚）之上。在砾岩-粘土界面上发生的速度反演对场地的放大特性具有重要意义。我们分析了近两年的数据，包括244个触发噪声记录和44个地震。两个数据集得到的结果显示出不同的场地响应特征。特别地，地震HVSR在1- 8Hz的频率范围内不像触发噪声HVSR那样被去放大。为了找出这种差异的根源，我们模拟了触发噪声和地震，利用一个改进的版本的Sparkson-Haskell传播矩阵方法。触发噪声放大函数和地震放大函数之间的差异可以用地震波场的组成和传播的差异来解释。此外，我们表明，非线性行为的人为填充可能解释存在的共振频率的失配归因于这一层之间的触发噪声和地震。
The aim of this work is to check the stability of the horizontal-to-vertical spectral ratios (HVSRs) calculated at the Venosa station site (Italy). This site lies over a layer of anthropogenic fill (4 m thick), a rigid layer of conglomerates (15 m thick), and a thick layer of clays (about 300 m thick) above the seismic bedrock. The velocity inversion, which takes place at the conglomerates-clays interface, is of main importance for the amplification behavior of this site. We have analyzed nearly 2 years of data, composed of 244 triggered noise records and 44 earthquakes. The results obtained by the two data sets show different site-response characteristics. In particular, the earthquake HVSR is not deamplified in the frequency range 1-8 Hz like the triggered noise HVSR. To find out the origin of this difference, we modeled both the triggered noise and the earthquakes, taking advantage of an improved ver- sion of the Thompson-Haskell propagation matrix method. The differences between triggered-noise- and earthquake-amplification functions might be explained by the difference in composition and propagation of the seismic wave fields. Moreover, we show that the nonlinear behavior of the anthropogenic fill might explain the presence of the misfit of the resonance frequency attributed to this layer between triggered noise and earthquakes.