Unit 9 - Essays - Mass Movements Flashcards
(4 cards)
‘Mass movement hazards vary in the extent to which they can be predicted and prepared for.’ How far do you agree with this view?
‘Mass movement hazards vary in the extent to which they can be predicted and prepared for.’ How far do you agree with this view?
Paragraph 1 – Low Predictability and Preparedness (Venezuela)
No monitoring systems or slope warning mechanisms.
Informal settlements in hazard-prone areas had no hazard education or risk mapping.
Rainfall was forecast but not converted into actionable warnings; over 30,000 died.
Paragraph 2 – Scientific Warnings Ignored (Sarno, Italy)
Hazard maps from 1980s existed but were not enforced.
Authorities permitted illegal construction on high-risk slopes.
Public unaware or dismissive of risks despite past landslides.
Paragraph 3 – Moderate Prediction but Poor Community Awareness (Puerto Rico)
Heavy rainfall forecast, but no direct landslide alerts or monitoring tech.
Hazard knowledge existed academically, not implemented in planning or local awareness.
Low risk perception in rural areas.
Paragraph 4 – High Prediction and Moderate Preparedness (European Avalanches)
Strong monitoring (snowpack, weather), daily avalanche bulletins.
Some mitigation structures (snow fences), but hazard zones downgraded in Galtür.
Perception high among professionals, lower among residents/tourists.
Paragraph 5 – Variation by Hazard Type and Setting
Debris flows and landslides are harder to predict than snowpack conditions.
MICs/LICs lacked infrastructure for early warning.
HICs better equipped but still underestimated scale or frequency.
Conclusion
Judgement: Agree to a large extent – prediction and preparedness vary widely by hazard type, location, and governance. Avalanches were best predicted, but landslides in LICs and MICs suffered worst from unpreparedness and poor risk perception.
Evaluate the most effective way of managing mass movement hazards.
Paragraph 1 – Hazard Mapping and Land-Use Planning
European Alps: Maps used to restrict construction in avalanche zones.
Sarno: Maps existed but ignored, leading to 160+ deaths.
Key to long-term resilience if enforced properly.
Paragraph 2 – Monitoring Systems
Avalanches: Daily forecasts based on slope, snow, weather data.
Sarno and Puerto Rico lacked real-time slope monitoring or rainfall thresholds.
Early warning depends on tech + local application.
Paragraph 3 – Structural Defences
Avalanche barriers, sheds, snow fences in Alps; sometimes outdated but useful.
Poor drainage and lack of embankments in Venezuela worsened disaster.
Engineering works reduce physical exposure but need updating.
Paragraph 4 – Community Education and Evacuation Preparedness
Galtür: Evacuation plans existed but were not fully trusted or rehearsed.
Puerto Rico & Venezuela: No drills, no warning systems, poor public understanding.
Critical to ensure residents act on warnings and understand risks.
Paragraph 5 – Governance and Enforcement
Venezuela & Sarno: Ignored expert advice; poor enforcement of building controls.
European cases show better coordination, but still weak in updating maps or enforcing no-build zones.
Conclusion
Judgement: The most effective management involves a combination of hazard mapping, monitoring, and education, but governance quality is the crucial link. Tech alone is not enough without proper implementation, enforcement, and communication.
Assess the extent to which physical factors, rather than human factors, cause mass movements.
Assess the extent to which physical factors, rather than human factors, cause mass movements.
Paragraph 1 – Physical Factors: Rainfall and Slope
Venezuela & Puerto Rico: Intense tropical rain triggered slope failures.
Sarno: 400 mm rain saturated volcanic ash.
Avalanches: Sudden warming and snow loading led to failure.
Paragraph 2 – Physical Geology and Terrain
Steep slopes (Puerto Rico, Sarno, Venezuela) increased gravitational stress.
Colluvial/pyroclastic soils lacked cohesion when wet.
Snowpack layering caused slab avalanches in Galtür.
Paragraph 3 – Human Land-Use Change
Deforestation (Puerto Rico, Sarno) removed slope stability.
Road-building altered runoff patterns and cut into slopes.
Tourism infrastructure in Alps increased exposure and pressure on hazard zones.
Paragraph 4 – Urbanisation and Informal Settlements
Sarno: Illegal housing built on hazard-prone slopes.
Venezuela: High-density, poorly built housing on unstable terrain.
Human presence in hazard zones turned natural processes into disasters.
Paragraph 5 – Infrastructure and Drainage Failures
Venezuela: No stormwater drainage led to waterlogging.
Puerto Rico: Poor road planning concentrated runoff.
Galtür: Defences were in place but underestimated storm magnitude.
Conclusion
Judgement: While physical causes (rainfall, slope, geology) initiate mass movements, human activity dramatically increases risk and scale. Disasters often occur where natural triggers meet human vulnerability.
‘Some types of mass movement are more hazardous than others.’ How far do you agree with this view?
‘Some types of mass movement are more hazardous than others.’ How far do you agree with this view?
Paragraph 1 – Debris Flows and Mudslides (High Hazard)
Sarno, Italy (1998): Fast-moving debris flows buried homes at night; 160+ deaths.
Highly mobile and occur with little warning, especially in densely populated areas.
Impact intensified when fine-grained volcanic soils become saturated.
Paragraph 2 – Flash Flood + Landslide Combinations (Very High Hazard)
Venezuelan Mudslides (1999): Deadliest case (~30,000 killed).
Mix of debris flows, flash floods, and landslides in densely built areas.
Coastal topography amplified hazard; entire communities destroyed.
Paragraph 3 – Deep Rotational Landslides and Rainfall-Induced Failures (Moderate to High Hazard)
Puerto Rico (1985): Landslides after 500 mm of rain; 129 deaths.
Impact depends on slope steepness, rainfall intensity, and human presence.
Hazard is often localised but severe where settlements are built on unstable slopes.
Paragraph 4 – Avalanches (Moderate Hazard but Highly Variable)
European Avalanches (1999): 70+ killed in ski resorts (e.g., Galtür).
Predictable in some conditions, mitigated with forecasting/barriers.
Most damage to tourists and property in high-income areas, not large-scale death.
Paragraph 5 – Variation Depends on Human Vulnerability and Location
Same process (e.g., landslide) can be low hazard in remote regions but catastrophic in urban areas.
Venezuela vs Puerto Rico: Similar rainfall triggers, but vastly different impacts due to density and preparedness.
Avalanches are dangerous but often better managed in HICs than landslides in LICs.
Conclusion – Judgement
Agree to a large extent: Debris flows and combined events (e.g., mudslides + floods) are inherently more hazardous due to speed, volume, and unpredictability. However, the level of hazard also depends on exposure, vulnerability, and preparedness, meaning even moderate hazards can become deadly under poor conditions.
