Mass Movement

Question 1

What is the driving force behind mass movement?

Answer 1

Gravity

Question 2

What are the four risk factors for mass movement?

Answer 2

1. Slopes
2. Weak Rocks
3. Lack of Vegetation
4. Excess Water

Question 3

Which one makes trees curve upward?

Answer 3

Creep

Question 4

Which one travels farther earthflow or mudflow?

Answer 4

Mudflow

Question 5

How can we reduce the risks of mass movement?

Answer 5

1. Cut one big slope into many smaller terraces to catch falling rocks.
2. Stabilize slopes with plants or walls
3. Divert water away
4. Leave talus piles

Question 6

At the highest risk for mass movement _______

But movement can happen even on very _____ ____

Answer 6

Steep slopes

Gentle slopes

Question 7

Rocks can be weak because of their ______ ( lots of soft clay)

Answer 7

composition

clay is bad

Question 8

Another thing that makes rocks weak, especially if tilted parallel to the slope

Answer 8

Plate tectonics

Cracks and bedding planes

Question 9

Slopes too steep and rocky for plants to move (more/less)

Answer 9

More

Question 10

When plants are killed by forest fires, mass movements……

Answer 10

Soon follow

Question 11

Water can mix with soil, mud or volcanic ash to make a thick slurry

Answer 11

Flow

Question 12

Water building up in cracks…..

Answer 12

Makes it easy for rocks to slide

Question 13

Individual rocks break and slide

Answer 13

Rockfall (slope failure)

Question 14

Pile of loose debris at base of slope.

Weight prevents worse movements

Answer 14

Talus (slope failure)

Question 15

One or more large blocks of rock moves as a jumbled mass

Answer 15

Rockslides (slope failure)

Question 16

Usually the result of titled layers

Answer 16

Rockslides

Question 17

Single block of rock and/or soil moves as one intact mass. Can move slowly or very fast.

Answer 17

Slumps (Slope Failure)

Question 18

Soil layers detach from bedrock and slide across it

Answer 18

Creep (dry flows)

THINK ABOUT JACKSON

Question 19

Warning signs of creep

Answer 19

TIlted walls and fences or curved tree trunks

Question 20

Rocks and soil mix with just enough water to make a soft ‘pudding’. Moves fast but not far

Answer 20

Earthflow (wet flows)

Question 21

Lots of water from floods mixed with fine clay or volcanic ash. This makes a natural concrete that can bury entire cities.

Answer 21

Mudflow (wet flow)