Melting of ground ice in near-surface permafrost can lead to ground subsidence in areas with ice-rich sediments7,8,9.
Thermokarst, land-surface configuration that results from the melting of ground ice in a region underlain by permafrost.
The thawing of permafrost creates thermokarst topography, an uneven surface that contains mounds, sinkholes, tunnels, caverns, and steep-walled ravines caused by melting of ground ice.
The melting of ground ice also contributes to subsidence such as the formation of glacial kettles and depressions following the seasonal surface thaw of perennially frozen land.
In the catchment, the thawing of permafrost and melting of ground ice creates thermokarst and causes altered lake chemistry and massive landslides into lakes.
The lithological suggestions of the age of the deposits allowed to determine two types of depressions - fossil depressions of melting origin, and genetically complex ones that underwent deposition prior to the Eemian Interglacial and with a secondary deepening, most likely as a result of melting of ground ice under thermokarst conditions, during the Vistulian Glaciation (=Weichselian).
Thermokarst lake formation is a dominant mode of permafrost degradation and is linked to surface disturbance, subsequent melting of ground ice, surface subsidence, water impoundment, and positive feedbacks between lake growth and permafrost thaw, whereas lake drainage generally results in local permafrost aggradation.
Ice-rich permafrost landscapes are sensitive to climate and environmental change due to the melt-out of ground ice during thermokarst development.
RTS stabilise in autumn as air temperatures drop below 0 °C and melting of the ground ice ceases.
More than 200 Alaskan towns risk having to relocate as the foundations of their buildings crumble due to the melting of frozen ground.
