Comparing single-station 6C measurements and array measurements for seismic microzonation in Munich, Germany
Comparing single-station 6C measurements and array measurements for seismic microzonation in Munich, Germany
复制标题
比较德国慕尼黑地震微分区的单站 6C 测量和阵列测量
DOI：
10.1093/gji/ggac273
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发表时间：
2022
影响因子：
2.8
通讯作者：
S. Kremers
中科院分区：
文献类型：
--
作者：
Sabrina Keil;Alexander Wilczek;J. Wassermann;S. Kremers
地震微区划的基本目标是估算浅层速度结构，以表征局部地震的震动特征。这在人口密集、土壤条件不利的地区尤为重要。常用的方法是使用频率-波数（FK）或空间自相关（SPAC）技术分析环境噪声阵列数据。然而，阵列的安装是困难的，特别是在城市环境中，使单站方法更可取。在这项研究中，我们直接比较了最近发展的使用单站六分量（6C）测量，结合三个平移和三个旋转运动的速度估计方法，以及已建立的FK和SPAC分析方法。我们分别使用检波器阵列和iXblue blueSeis-3A旋转运动传感器以及nanomeics Trillium紧凑型地震仪在慕尼黑内城进行测量。从阵列数据以及6C数据中，估计并进一步反演了一维纵波和横波速度剖面的Love和Rayleigh色散曲线。我们发现所有的方法都给出了相似的结果，这表明了新型6C方法的潜力。此外，增加水平-垂直谱比可以在更大的深度反演结构，并提高速度结构的分辨率。此外，我们测试了不同的阵列几何形状，以评估传感器配置对结果的影响。作为最后一步，我们将估计的速度模型与岩性剖面进行比较，发现两者总体正相关，这支持了我们的反演结果。
The essential goal of seismic microzonation is the estimation of the shallow velocity structure in order to characterise the local earthquake shaking characteristics. This is of special importance in densely inhabited areas with unfavorable soil conditions. The common approach is the analysis of ambient noise array data using frequency-wavenumber (FK) or spatial autocorrelation (SPAC) techniques. However, the installation of arrays is difficult, especially within urban environments, making single-station approaches more desirable. In this study, we directly compare the recently developed approach of velocity estimation using single-station six-component (6C) measurements, combining three translational and three rotational motions, with the established methods of FK and SPAC analysis. We conduct measurements in Munich’s inner city using a geophone array and an iXblue blueSeis-3A rotational motion sensor together with a Nanometrics Trillium Compact Seismometer, respectively. From the array data, as well as from the 6C data, Love and Rayleigh dispersion curves are estimated and further inverted for 1D P- and S-wave velocity profiles. We find that all methods give similar results, indicating the potential of the novel 6C approach. Furthermore, adding horizontal-to-vertical spectral ratios enables the inversion for structures at greater depth and increases the resolution of the velocity structure. In addition, we test different array geometries to evaluate the influence of the sensor configuration on the results. As a last step, we compare the estimated velocity models to lithologic profiles and find an overall positive correlation, which supports our inversion results.