Mass Wasting & SubsidenceMass Wasting & Subsidence

Week 5Week 5

Questions for DiscussionQuestions for Discussion

Would you live on a slope or area prone to subsidence? If so, where?

What level of risk from mass wasting or subsidence is acceptable to you? (How would you know if the slope risk was assessed accurately?)

What should be done by people and communities in areas prone to slope failure and subsidence to prepare for the hazard and prevent catastrophe?

Would you live on a slope or area prone to subsidence? If so, where?

What level of risk from mass wasting or subsidence is acceptable to you? (How would you know if the slope risk was assessed accurately?)

What should be done by people and communities in areas prone to slope failure and subsidence to prepare for the hazard and prevent catastrophe?

Other Questions to ConsiderOther Questions to Consider

What factors impact the stability of a slope?

What areas are prone to subsidence? (natural or human-induced)

The five concepts form Chapter 1

What factors impact the stability of a slope?

What areas are prone to subsidence? (natural or human-induced)

The five concepts form Chapter 1

Mass MovementsMass Movements Mass Wasting

Down slope movement of earth materials

Caused by gravity Subsidence

Vertical movement Caused by loss of support

Mass Wasting Down slope movement of earth

materials Caused by gravity

Subsidence Vertical movement Caused by loss of support

Structural damage Surface disruption

Structural damage Surface disruption

Impact of Mass Movements

Impact of Mass Movements

Slope FactorsSlope Factors Angle of slope Water content Material composition Material orientation Vegetation Loading Undercutting Weathering of materials

Angle of slope Water content Material composition Material orientation Vegetation Loading Undercutting Weathering of materials

Slope Movement TriggersSlope Movement Triggers

Rainfall Vibration Undermining Loading

Rainfall Vibration Undermining Loading

Types of Slope

Failures

Types of Slope

Failures Slides Flows Falls Creep Avalanche

Slides Flows Falls Creep Avalanche

Addressing Unstable Slopes

Addressing Unstable Slopes

Identification & mapping Slope monitoring Stabilization

vegetation water removal structural controls

Identification & mapping Slope monitoring Stabilization

vegetation water removal structural controls

Subsidence Causes

Subsidence Causes

Cave Collapse Groundwater loss Expandable soils Mining Tectonic movement

Cave Collapse Groundwater loss Expandable soils Mining Tectonic movement

SinkholeSinkhole

Addressing SubsidenceAddressing Subsidence Identification & mapping Planned subsidence Insurance

Identification & mapping Planned subsidence Insurance

Karst Prone Areas

Potentially Undermined Areas