Replication data for: Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway

This data set is used to conduct research as presented in the manuscript entitled \"Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway\" written by Taweesintananon et al. in 2024, which is submitted for peer reviews and publications in a journal. It contains processed strain data in nanostrain unit measured by OptoDAS interrogator through the dark fibers in two submarine telecommunication cables, which were installed into soft sediments at 0–2 m below the seafloor, between Longyearbyen and Ny-Ålesund in Svalbard, Norway. In total, four OptoDAS interrogators are used for DAS data recording: the ends of the inner (L2) and outer (L3) cables in Longyearbyen, and the other ends of the inner (N2) and outer (N3) cables in Ny-Ålesund. The raw data were acquired in August, 2022, and converted to strain data in nanostrain unit. To reduce file sizes, we resampled the DAS strain data from 1.6 to 20 ms time sampling intervals with an antialiasing filter at 80% of the output Nyquist frequency of 25 Hz. After that, we attenuated interrogator noise that occurs in every DAS recording channel. First, we obtained the single-trace interrogator noise model by stacking (a mean calculation) all the DAS data traces in the first 40 km of the cable, in which the instrument noise level was low. Then, we subtracted every trace of the DAS data by the interrogator noise model. The resampled data after the interrogator noise removal have been archived and used in our spectral analysis. The processed data and the power spectra are stored as structured arrays in the MATLAB file format. This data set has no exact positioning data of the fiber optic cable, because they are proprietary to Sikt. However, the distance of each recording channel along the cable from the shore is given in this data set.本数据集用于支撑Taweesintananon等人于2024年撰写的题为《利用剪切波共振开展近地表特征表征——挪威斯瓦尔巴群岛近海案例研究》的手稿研究，该手稿已提交至期刊等待同行评审与发表。数据集包含由OptoDAS解调仪（OptoDAS interrogator）通过两条海底通信光缆中的暗光纤采集得到的、以纳应变为单位的处理后应变数据。两条光缆铺设于挪威斯瓦尔巴群岛朗伊尔城（Longyearbyen）与新奥勒松（Ny-Ålesund）之间的海底0–2米深的软沉积物中。本次数据记录共使用4台OptoDAS解调仪，分别部署于朗伊尔城处的内缆（L2）与外缆（L3）末端，以及新奥勒松处的内缆（N2）与外缆（N3）末端，用于分布式光纤声波传感（Distributed Acoustic Sensing, DAS）数据采集。原始数据采集于2022年8月，后被转换为纳应变单位的应变数据。为压缩文件体积，研究团队采用抗混叠滤波器（设置为输出奈奎斯特频率25 Hz的80%），将DAS应变数据的时间采样间隔从1.6 ms重采样至20 ms。随后，研究团队对每一条DAS记录通道中出现的仪器噪声进行了压制处理。具体步骤为：首先选取光缆前40 km段（该段仪器噪声水平较低）的全部DAS数据道进行叠加（即求取均值），得到单道仪器噪声模型；随后将该噪声模型从每一道DAS数据中减去，完成噪声压制。完成仪器噪声压制与重采样后的数据已被归档，用于后续的频谱分析。本数据集的处理后数据与功率谱均以结构化数组形式存储于MATLAB格式文件中。本数据集未提供光缆的精确位置信息，因该信息归属于Sikt公司所有。不过，数据集中提供了各记录通道沿光缆至海岸的距离。