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Learning Objectives: Supplement
• Understand the types of subsidence and the causes of each type
• Key controls of subsidence processes, and mitigation
• Human effects that promote or mitigate subsidence
Terminology
• Subsidence/collapse– Surface depressions resulting from failure of
rock/soil from deeper(underground) perturbations; usually associated with material removal by natural or human influences.
Types of Subsidence
• Subsidence at or near the surface: (Volume losses)
• Withdrawal of fluids
• Underground Mining
• Dissolution of limestone or salt deposits
Subsidence at or near the surface: (Volume losses)
• Above compressible (fine-grained) sediments
• Associated with clayey soils
• Draining or decomposition of organic deposits
Underground Mining
• Material withdrawal (especially coal)– Room & Pillar mining– Longwall mining
• Mine fires
Dissolution of Limestone: Sinkholes, Karst Topography
• Controlling Factors
• Promoting Factors
• Types
• Examples
• Human Effects