frozen ground or permafrost

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volumetric heat capacity

the amount of heat required to raise the temperature of a unit volume of a substance by one degree.

volumetric latent heat of fusion

the amount of heat required to melt all the ice (or freeze all the pore water) in a unit volume of soil or rock.

waterbody encircling a palsa

a water-filled depression surrounding a palsa.

wedge ice

ice occurring in an ice wedge.

well-bonded permafrost

ice-bearing permafrost in which all the soil particles are held together by ice.


A type of Pleistocene-age (formed 1.8 million to 10,000 years before present) permafrost that contains a significant amount of organic material with ice content of 50–90% by volume. Thawing yedoma is a significant source of atmospheric methane.
A yedoma in Russia shows the thick layer of ice and carbon material exposed along this body of water. --Credit: Vladimir Romanovsky

Young's Modulus

the ratio of increase in stress acting on a test specimen, to the resulting increase in strain, under constant transverse stress.

zero curtain

the persistence of a nearly constant temperature, very close to the freezing point, during annual freezing (and occasionally during thawing) of the active layer.

zone of gas-hydrate stability

that portion of the subsurface where the conditions of temperature and pressure are suitable for the formation and preservation of gas hydrates.