Data for the figures in the manuscript: S. K. Sahoo, H. Marin-Moreno, L. J. North, I. Falco-Suarez,B. N. Madhusudhan, A. I. Best and T. A. Minshull (2018).Presence and consequences of co-existing methane gas with hydrate under two phase water-hydrate stability conditions , Journal of Geophysical Research: Solid Earth. https://doi.org/10.1029/2018JB015598

This dataset is of laboratory ultrasonic shear wave measurements during methane hydrate formation in water saturated Berea sandstone using pulse echo method. We formed methane hydrate and took shear wave measurements during the formation process at different time interval. The hydrate saturation was calculated from measured pressure and temperature changes. This data set was used to show how shear wave velocity and attenuation can be used to estimate permeability of hydrate-bearing geological formations. We observed that velocity and attenuation both increase with hydrate saturation, with two peaks in attenuation at hydrate saturations of around 6% and 20% that correspond to changes in gradient of velocity. These laboratory experiments were conducted in National Oceanography Centre, Southampton by Sourav Sahoo with technical support provided by Laboratory Manager Laurence North. Sourav Sahoo interpreted the data. The hydrate formation process continued for few days and measurements were done mostly during daytime due to limited laboratory access during the night. This data set has been used for the paper published in Journal of Geophysical Research: Solid Earth (DOI 10.1029/2021JB022206)

Health and safety documentation for the Geophysical methodologies for the characterisation of gas hydrate core (HYDRAGAS) project.

Through manufacturing and geophysically characterising the properties and distribution of a range of synthetic gas hydrate morphologies in a range of sediments in the laboratory, protocols will be established for geophysically logging natural sediment-hydrate core preserved in pressure chambers on board ship. Based on pressure cycling, geophysical behaviour responses will be determined during the start of dissociation and formation. On this basis the investigators then propose to develop protocols to characterise and classify hydrates sampled during ODP Leg 204, significantly improving our understanding of the nature and behaviour of these sediments. This new knowledge will enhance geophysical survey data, better constrain estimates of in-situ hydrates and improve the evaluation of hydrate destabilisation on methan release and slope stability.