EOSC 114 LANDSLIDES Questions with
Correct Answers
Why do we study landslides
- infrustracture damage and can trigger secondary disasters
**Explain how the impact of landslides depends on the affected area's population
density, economic infrastructure, and population preparedness.
When is our vulnerability to landslides increased
- impact fo landslides is increased by
- increasing population density --> higher the density, the more lives lost
- use of marginal land
- rapid land-use change
- global warming.
What type of consequences cause the most devastating landslide disasters
landslide disasters with both direct and indirect consequences
Which country suffers the most from landslides?
asia --> higher population density
north america is pretty low
Elm Event, Switzerland 1881
- sudden release of 10 mil m^3 of rock, ~100 died
- 288 km/h (80 m/s)
- failure of slope due to extraction of slate from quarry located at the foot of the slope
- developed by farmer with no mining/geological experience
,La conchita, Californina 1995 and 2005
- 2005 event was 1/6 and half of the mass of the 1995 event --> reactivation of the 1995
landslide
- both caused by heavy rainfall
- these two landslides are part of a historic landslide site --> very vulnerable area to landslides
due to tectonic uplift, weak foundation etc.
- could have been avoided if engineering work was done prior to development of the area
Haiyuan, Ningxia Landslide 1920
- number 3 on wikipedia's list of deadliest earthquakes
- 2000000 deaths due ti direct damage of homes and exposure to winter climate (indirect
damage)
-caused by an earthquake
Rockfall and slide events
- smaller rockmass that disintegrates into numerous blocks that fall over slopes
- does not pose as large of an economic risk as large scale failures which can close major
transportation routes
Mass Movement
- also called mass wasting
- downslope motion of soil/rock under influence of gravity
landslide
- general term for mass movements
- occurs when gravitational force pulling downslope exceeds slope materials internal
, resistance
- material move down sliding along weak failure planes or number of failure planes
Effects of Gravity
- on dif surfaces
- main force responsible for landslides
- on a flat surface --> gravity acts downwards (object does not move on a flat object)
- on a slope, gravity is split into two components
1. Gp - acts perpendicular to slope (holds an object in place on a slope)
2. Gt - acts tangential/parallel to slope
- pulls an object down the slope and causes shear stress
What is the main force responsible for landslides
gravity
What are the two components of gravity acting on a slope?
What components creates shear stress?
When slope is steeper what happens?
On a flat surface?
Gp (perpendicualr) and Gt (parallel)
Correct Answers
Why do we study landslides
- infrustracture damage and can trigger secondary disasters
**Explain how the impact of landslides depends on the affected area's population
density, economic infrastructure, and population preparedness.
When is our vulnerability to landslides increased
- impact fo landslides is increased by
- increasing population density --> higher the density, the more lives lost
- use of marginal land
- rapid land-use change
- global warming.
What type of consequences cause the most devastating landslide disasters
landslide disasters with both direct and indirect consequences
Which country suffers the most from landslides?
asia --> higher population density
north america is pretty low
Elm Event, Switzerland 1881
- sudden release of 10 mil m^3 of rock, ~100 died
- 288 km/h (80 m/s)
- failure of slope due to extraction of slate from quarry located at the foot of the slope
- developed by farmer with no mining/geological experience
,La conchita, Californina 1995 and 2005
- 2005 event was 1/6 and half of the mass of the 1995 event --> reactivation of the 1995
landslide
- both caused by heavy rainfall
- these two landslides are part of a historic landslide site --> very vulnerable area to landslides
due to tectonic uplift, weak foundation etc.
- could have been avoided if engineering work was done prior to development of the area
Haiyuan, Ningxia Landslide 1920
- number 3 on wikipedia's list of deadliest earthquakes
- 2000000 deaths due ti direct damage of homes and exposure to winter climate (indirect
damage)
-caused by an earthquake
Rockfall and slide events
- smaller rockmass that disintegrates into numerous blocks that fall over slopes
- does not pose as large of an economic risk as large scale failures which can close major
transportation routes
Mass Movement
- also called mass wasting
- downslope motion of soil/rock under influence of gravity
landslide
- general term for mass movements
- occurs when gravitational force pulling downslope exceeds slope materials internal
, resistance
- material move down sliding along weak failure planes or number of failure planes
Effects of Gravity
- on dif surfaces
- main force responsible for landslides
- on a flat surface --> gravity acts downwards (object does not move on a flat object)
- on a slope, gravity is split into two components
1. Gp - acts perpendicular to slope (holds an object in place on a slope)
2. Gt - acts tangential/parallel to slope
- pulls an object down the slope and causes shear stress
What is the main force responsible for landslides
gravity
What are the two components of gravity acting on a slope?
What components creates shear stress?
When slope is steeper what happens?
On a flat surface?
Gp (perpendicualr) and Gt (parallel)
