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).