P-wave velocity and attenuation (1/Q) data of ice-bearing sand pack during melting measured using an acoustic pulse tube under 2.5 MPa effective pressure

The data comprise P-wave velocity and attenuation (1/Q) measurements of ice-bearing sand packs across ice saturation levels during melting, from frozen to fully melted conditions. Using an acoustic pulse tube, measurements were recorded in the sonic frequency range (1-20 kHz, centred at 10 kHz) under 2.5 MPa effective pressure with atmospheric pore pressure. Data were collected in the Pulse Tube Laboratories at the National Oceanography Centre (NOC), Southampton, between March and July 2023, funded by the Natural Environment Research Council (NERC Grant NE/J020753/1), and primarily collected and analysed by Hanif Sutiyoso (University of Southampton). The experiment aimed to fill gaps in sonic frequency measurements of ice-bearing sediment/permafrost, particularly during melting/thawing, providing a spectrum of ice/water saturation rather than a single value. This dataset is valuable for researchers analysing thawing/melting permafrost, and is directly comparable to sonic well-logging field data due to its frequency range, and potential for monitoring application. The work regarding this dataset can be found at: https://doi.org/10.22541/essoar.172854543.39791425/v1.
The method involved measuring the time series of signal amplitude from two ice-bearing sand samples inside a 4.5 m water-filled acoustic pulse tube, which allows plane wave propagation in the sediment-jacketed samples. Time-domain data were transformed into the frequency domain using the Fast Fourier Transform (FFT) and deconvolved with the chirp source signal to obtain the impulse response. Nonlinear inversion was used to minimize an objective function derived from initial time-domain estimates, determining the sample's complex velocity and attenuation (1/Q).

数据涵盖了含冰砂样在融化过程中（从冻结到完全融化状态）不同冰饱和度水平下的纵波速度与衰减（1/Q）测量结果。通过声波脉冲管，在有效压力2.5 MPa、孔隙压力为大气压的条件下，于声波频率范围（1-20 kHz，中心频率10 kHz）内记录测量数据。数据于2023年3月至7月在南安普顿英国国家海洋学中心（NOC）的脉冲管实验室采集，由自然环境研究委员会资助（NERC基金NE/J020753/1），主要采集与分析工作由南安普顿大学的Hanif Sutiyoso完成。本实验旨在填补含冰沉积物/多年冻土声波频率测量领域的空白，尤其是在融化/解冻过程中的测量空白，提供冰/水饱和度的连续谱而非单一数值。该数据集对研究解冻/融化多年冻土的学者具有重要价值，因其频率范围与声波测井现场数据直接可比，且具备监测应用潜力。关于该数据集的研究成果可查阅：https://doi.org/10.22541/essoar.172854543.39791425/v1。
该方法包括在4.5米充水声波脉冲管内测量两个含冰砂样的信号振幅时间序列，该脉冲管可使平面波在沉积物包裹的样品中传播。时域数据通过快速傅里叶变换（FFT）转换至频域，并与线性调频源信号进行反卷积以获取脉冲响应。采用非线性反演方法最小化由初始时域估计值导出的目标函数，从而确定样品的复速度与衰减（1/Q）。