Landslide Causes and Landslide Triggers
Landslide Causes and Landslide Triggers
Compare and contrast landslide causes and landslide triggers. o Cause factors leading to instability o Triggers translate instability into motion
List and describe several external causes of landslides. o High slope angle o Undercutting o Overloading o Vegetation o Climate
List and describe 3 internal causes landslides. o Water in slopes Adds weight (overloading) Decreases normal force/normal stress which decreases friction and thus, shear strength
Increases weathering Acts as a medium for flows
o Water in sediment Can help or hinder cohesion No water = low angle of repose, some water = high, too much water = very low angle
o Water in solid rock Water reduces shear strength along planes of weakness Frost wedging, water gets into cracks and fractures in rocks – freezes and expands forcing fractores apart
o Inherently weak materials Some materials are weak Volcanic layers Clay Quick clay slides not common
o Adverse geologic structures
Unfortunate bedding or fracture orientation
List several landslide triggers. o Earthquakes, snow melt, heavy rainfall, rain on snow, loud noises, vehicles, volcanic eruptions, excavation, skiing, jumping up and down
Compare and contrast key triggers and causes of landslides and how they affect the force balance equation (i.e. factor of safety).
Explain how liquefaction landslides develop in sensitive marine clays (quick clay slides).
List and describe the site conditions (causes and trigger) that lead to the development of the Rissa quick lay slide Norway.
Relate the type of landslide damage expected as function of its velocity.
Identify tell-tale signs of an unstable slope.
o Internal + External causes
o Rainfall, water-level change, volcanic eruption, rapid erosion, earthquake shaking, rapid snowmelt
Compare and contrast avoidance, prevention and protection strategies for dealing with landslide hazards.
List the mitigation techniques commonly used for avoidance, prevention and protection strategies. o Avoidance – move to different area o Prevention – do something to make sure events don’t occur (removal, stabilizing slopes, drainage) o Protection – armour or strengthen the area that might be affected (barriers and netting, netting and fences, debris flow – separate water from debris)
Identify the appropriate mitigation strategy for a variety of risk situations.
Compare and contrast landslide causes and landslide triggers. o Cause factors leading to instability o Triggers translate instability into motion
List and describe several external causes of landslides. o High slope angle o Undercutting o Overloading o Vegetation o Climate
List and describe 3 internal causes landslides. o Water in slopes Adds weight (overloading) Decreases normal force/normal stress which decreases friction and thus, shear strength
Increases weathering Acts as a medium for flows
o Water in sediment Can help or hinder cohesion No water = low angle of repose, some water = high, too much water = very low angle
o Water in solid rock Water reduces shear strength along planes of weakness Frost wedging, water gets into cracks and fractures in rocks – freezes and expands forcing fractores apart
o Inherently weak materials Some materials are weak Volcanic layers Clay Quick clay slides not common
o Adverse geologic structures
Unfortunate bedding or fracture orientation
List several landslide triggers. o Earthquakes, snow melt, heavy rainfall, rain on snow, loud noises, vehicles, volcanic eruptions, excavation, skiing, jumping up and down
Compare and contrast key triggers and causes of landslides and how they affect the force balance equation (i.e. factor of safety).
Explain how liquefaction landslides develop in sensitive marine clays (quick clay slides).
List and describe the site conditions (causes and trigger) that lead to the development of the Rissa quick lay slide Norway.
Relate the type of landslide damage expected as function of its velocity.
Identify tell-tale signs of an unstable slope.
o Internal + External causes
o Rainfall, water-level change, volcanic eruption, rapid erosion, earthquake shaking, rapid snowmelt
Compare and contrast avoidance, prevention and protection strategies for dealing with landslide hazards.
List the mitigation techniques commonly used for avoidance, prevention and protection strategies. o Avoidance – move to different area o Prevention – do something to make sure events don’t occur (removal, stabilizing slopes, drainage) o Protection – armour or strengthen the area that might be affected (barriers and netting, netting and fences, debris flow – separate water from debris)
Identify the appropriate mitigation strategy for a variety of risk situations.
