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
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
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