Landslides

Front 1

Mass Wasting

Back 1

Ex: earth flows, rockfalls, avalanches

Front 2

Slope Processes

Back 2

High Cliff/free face
Talus Slope
Convex Slope
Straight Slope
Concave Slope

Front 3

Types of Landslides- (Fall)

Back 3

Free fall of earth

*Rockfall

Front 4

Types of Landslides- (Sliding)

Back 4

Movement of material as coherent block

*Slump (sliding along a curved plane)

Front 5

Types of Landslides- (Flows)

Back 5

Movement of Unconsolidated material

*creep (very slow)
*earth flow, debris flow, and avalanche (very fast)

Front 6

Driving Forces

Back 6

Move materials downslope

*due to vegetation, fill material, buildings that are placed on slope

Front 7

Resisting Force

Back 7

Oppose downslope movement

*shows strength of the material along slip planes

Front 8

Safety Factor (SF)

Back 8

Ratio of resisting forces to driving forces

*Stable >1, unstable <1

Front 9

Mineral Composition

Back 9

Weak pyroclastic materials produce: creep, earth flows, debris flows, and slump

When very resistant rock hangs over weak rock (pic): Rockfall

Front 10

Degree of Consolidation

Back 10

Unconsolidated material: Slumps

When unconsolidated materials are over bedrock (pic): Soil Slip

Front 11

Permeability? (seeps up water)

Back 11

When layers have contrasts in permeability SOIL SLIPS occurs.

Front 12

Zones of Weakness?

Back 12

Slip planes (natural breaks in soil consistency)

Rotational slides (curved slip surfaces)

Translational Slides (planar slip surfaces)

(SEE PICS TO UNDERSTAND)

Front 13

Steepness of the slope or incline?

Back 13

The steeper the slope the greater the driving force

Steep: rockfalls, avalanches, soil slips
Moderate: earth flows
Gentle: creep

Front 14

Topography Relief or height of hill determines what?

Back 14

The higher up the more risk of mass wasting

Front 15

Climate on Landslides

Back 15

1.) Timing of WATER flow

2.) Type and amount of VEGETATION:

Arid-rock falls, debris flows, soil slips

Humid- landslides, earth flows, and creep

Front 16

Vegetation's Affect

Back 16

1.) Provides protective cover, slowing surface erosion
2.) Roots at strength and cohesion to slope materials
3.) Adds weight to slopes

Front 17

Waters Affect

Back 17

1.) Saturates soil causing soil slips and debris flows
2.) After deep infiltration of water slumps occur as well
3.) Erodes base of slope, decreasing stability
4.) Can cause spontaneous LIQUEFACTION or QUICK CLAY

Front 18

Times Affect

Back 18

1.) Forces change
2.) DRIVING AND RESISTING FORCES CHANGE WITH SEASON DUE TO CHANGES IN MOISTURE CONTENT OR WATER TABLE
3.) Chemical erosion occurs slowly overtime as well

Front 19

Snow Avalanches

Back 19

-Rapid downslope movement of snow and ice
-Thousands occur each year in US and Canada
-Move down chutes (AVOID THESE)
- Slopes >25 degrees are unstable
- Stability of snowpack
-Weather
-Difference types:
Loose-snow and slab (see other notecard)

Front 20

Loose-snow Avalanche

Back 20

Widen as they move downslope

Front 21

Slab Avalanches

Back 21

-Move as a block
-Dangerous and damaging
-Caused by overloaded slope or weakness in snow

Front 22

Places at risk for Landslides

(and places expected to increase risk)

Back 22

*Anywhere with significant slopes and mountains are at risk

1.) Urbanization in landslide-prone areas
2.) Cutting trees in those areas
3.) Changing global climate patterns

Front 23

Effects of Landslides?

Back 23

1.) Can do significant damage (In US 25 people killed each year and costs >$1billion)
2.) People are buried by them
3.) Damage roads, homes, and utilities
4.) Blockage of roads, impeding travel
Blockage of streams, causing floods
5.) Disease

Front 24

Links to which hazards?

Back 24

Almost all of them!
(Earthquakes, fires, volcanoes, storms)

and they can cause flooding or tsunamis

Front 25

Human Interaction

Back 25

-Natural phenomenon

Humans Increase it by:
Expanding in urban areas and using natural resources

Humans Decrease it by:
Land grading (material from upper slope moved to bottom) to increase surface instability and building stable structures and proper drainage/slope supports

Front 26

How to identify potential landslides?

Back 26

1.) Tongue shaped masses of sediment at bottom of lope
2.) Irregular land surface at bottom of slope
3.) Refer to a hazardous map

Front 27

High cliff or free face?

Back 27

A high, steep, or overhanging face of rock.

Front 28

Talus Slope

Back 28

A sloping mass of rock fragments at the foot of a cliff

Front 29

Convex Slope

Back 29

A slope element, and sometimes an entire slope, which gets progressively steeper downhill. (domes over)

Front 30

Straight Slope

Back 30

I'm guessing it's flat and straight? idk

Front 31

Concave Slope

Back 31

A slope which becomes progressively shallower downhill