Collapse–subsidence retrogressive thaw slumps in degrading permafrost: multi-source insights from the Northeastern Qinghai–Tibet Plateau - Shunshun Qi; Dun Chen; Guoyu Li; Mingtang Chai; Yougang Yang; Qingsong Du; Yapeng Cao; Hang Zhang; Jintao Jiang; Anshuang Su; Miao Wang (Landslides, 2026)