Landslides 1 Flashcards
What is mass wasting?
used by farmers when landslide wreck the land / crops
Why are reported landslide fatalities (wrongfully) low?
most fatalities are associated with the trigger (EQ, flood, etc) and not the landslide itself
Turtle Mountain
“Mountain that walks”
ex/ Frank Slide, Alberta
Why are some landslides more deadly?
had higher vulnerability / people in the way
ex/ Peru (less rock but had ppl) vs Pemberton (more rock but no ppl)
Human and economic impacts of landslides are broadly governed by?
- population density
- cost of infrastructure
- population preparedness
How often does a landslide occur?
everyday!
-> some piece falls off
How often does a landslide occurs that closes a highway?
probably 1-10 yrs
ex/ porteau cove rockslide
Why is Japan much more affected by landslides?
higher population density
~200 lives/yr whereas in Canada it’s ~3 lives/yr
Economic impacts of landslides
impossible to determine
estimates:
Canada ~$1.4 billion/yr
US ~$3.5 billion/yr
Japan ~$4 billion/yr
Venezuela ~$62 Million /yr
(cost of rebuilding is less)
Landslides are considered more fatal when
there is more people affected
What are some causes of landslides?
mountains
rain
EQ
ice thawing
Classify landslides based on
- type of material
- type of motion
- rate of movement
Type of materials
- rock
- soil
- mud
- debris (combo of rock, trees, water, stuff)
Type of motions
- falls
- slides
- flows
- complex movements
What is a slide?
- material moves as a coherent mass along a surface of failure
- vary from slow to fast
- usually soil, rock, debris
Rotational slide / slump
- rotation of material on a curved failure surface
- intermediate speed
- usually weak material
- often a curved scarp above slide
Translational slide
like a kid down a slide
- cohesive motion of material along a flat failure surface
- slow to fast
- usually strong material moving on planes of weakness
If a slide moves slowly, what do we call it?
- creep
- soil flow
- earth flow
what is a flow?
- like fluid, moves independently around stuff (chaotic)
- very slow to very fast
- soil, mud, WET debris
- water very important
what is a fall?
- occur on very steep slopes
- usually rock
- material detaches cuz weakness / fractures
- falls cuz gravity, very fast
What is a scarp?
Above the slide, part where it breaks off
-> NOT to be confused with failure surface!
What are complex movements?
combo of the mass movements
ex/ slide that becomes a fall
