Underground karst in areas of permafrost. Karstification is due to the solvent action of subpermafrost (or intrapermafrost) water [20]. Synonyms: (French.) karst sous-permafrost; (German.) Pseudokarst; (Greek.) karst ypomonimou paghetou; (Italian.) carsismo di subpermafrost; (Russian.) podmerzlotny karst, mezmerzlotny karst; (Spanish.) karst de subpermafrost, karst de intrapermafrost; (Turkish.) don alani yeralti karsti. See permafrost karst. See also intrapermafrost karst.