Which ground surface instability event increases as permafrost thaws?

💡 Explanation

Thermokarst lakes expand because permafrost thaw weakens the previously frozen ground due to seasonal thaw depth exceeding the past active layer thickness; therefore lake expansion happens rather than deposition as previously stable terrain subsides.

• Which outcome results when acidic rainwater accelerates mineral dissolution?
• Which outcome occurs when a steep mountain slope underlying a glacial cirque thaws, exceeding its angle of repose?
• Which process drives the formation of horst and graben structures along a normal fault?
• Which risk increases along strike-slip plate boundary regions?
• Which outcome occurs when isostatic equilibrium shifts post-glacially for islands?
• Which outcome arises when parent material is exposed?