Mass movement

Question 1

What is mass movement

Answer 1

Mass movement is the movement downslope of any lose materials under the influence of gravity.

Question 2

What is gradient as an influence on mass movement

Answer 2

Mass movement is faster when the slope is steeper

Question 3

What is regolith

Answer 3

The loose material that falls off. E.g soil, mud

Question 4

Water content as an influence on mass movement

Answer 4

Water makes the regolith heavier and acts as a lubricant. This allows it to move quicker

Question 5

Name the 3 types of mass movement

Answer 5

Landslides, soil creep and mudflows

Question 6

Describe a mudflow

Answer 6

• mudflows are moving rivers of rock, soil and water. They are the fastest form of mass movement
• LAHARS are very dangerous mudflows that result from volcanic activity. E.g Nevado del Ruiz, in Columbia
• a bog burst is a form of mudflow. It is when peat becomes saturated with water after heavy rainfall.

Question 7

Nevado del Ruiz (case study)

• where?
• when?
• town affected
• how it was created
• depth and speed of mudflow
• 3 effects

Answer 7

• Columbia Andes
• 1984
• Armero
• the heat from the eruption melted the snow on the volcano. The meltwater cascaded down the mountainside p, picking up ash soil and rocks on way. Ash/soil and water = mudflow
• 20metres deep and 30km per hour
• 1)more than 21k killed
  2) over 5k homes destroyed
  3) 6k people made homeless