L3: Soils, Mass Wasting and Landscape development

Question 1

Topography

Answer 1

Different heights give shape to earth’s surface

Question 2

Relief

Answer 2

Difference between highest and lowest point in an area

Question 3

Geodesy

Answer 3

Study of Earth’s shape and surface

Question 4

Mass Movement

Answer 4

The movement of materials downslope under the influence of gravity

Question 5

3 factors contributing to mass movements

Answer 5

1) Nature of Material (Consolidated, Unconsolidated, type of particles)
2) Amount of water present
3) Steepness (defines Fall, slide or flow)

Question 6

Angle of repose

Answer 6

Stable slope angle for a material

Question 7

Angle of repose affected by (3)

Answer 7

Size
Shape
Cohessivness

Question 8

Debris

Answer 8

Unconsolidated mixture

Question 9

Cohesion

Answer 9

Attraction between close particles (Cementation or moisture)

Question 10

Liquefaction

Answer 10

Soil liquefaction occurs when a saturated soil substantially loses strength and stiffness in response to applied stress in which material that is ordinarily a solid behaves like a liquid.

Question 11

Rubble

Answer 11

Angular broken rock fragments

Question 12

Talus or Scree

Answer 12

Talus slopes are debris piles on the bottom of cliff faces that are stable up to a characteristic angle of repose.

Question 13

3 factors of classification of mass movements

Answer 13

1) Nature of material
2) Velocity of Material
3) Nature of movement

Question 14

Slides

Answer 14

material moving together as a single unit

Question 15

Flows

Answer 15

Mass movements characterized by large quantities of water allowing to material to behave like a liquid

Question 16

Rockfall

Answer 16

Rocks falling off the cliff face after being weakened

Question 17

Rockslides

Answer 17

Large masses of rock sliding downwards as a unit typically along bedding planes

Question 18

Rock avalanches

Answer 18

Large masses of small pieces of rock sliding on cushions of air at high speeds

Question 19

Soil creep

Answer 19

Soil creep defines the slow mass wasting process of soil on a slope, under the influence of gravity

Question 20

Solifluction

Answer 20

Solifluction is a collective name for gradual processes in which a mass moves down a slope related to freeze-thaw activity.

Question 21

Earthflow

Answer 21

Earthflow is a downslope viscous flow of fine-grained materials that have been saturated with water and moves under the pull of gravity. It is an intermediate type of mass wasting that is between downhill creep and mudflow. Though earthflows are a lot like mudflows, overall they are slower and are covered with solid material carried along by flow from within

Question 22

Debrisflow

Answer 22

Debris flows are when water-laden debris (masses of soil and fragmented rock) rush down mountainsides,

Question 23

Mudflows

Answer 23

Mudflows is the fast mass wasting of fine-grain materials such as clay or ash, happening when they are saturated with water.

Question 24

Lahar

Answer 24

A lahar is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley.

Question 25

Debris avalanche

Answer 25

A debris avalanche is the mass wasting of debris with large amounts of water on very steep slopes. It is the sudden catastrophic collapse from an unstable side of a volcano. Many volcanic cones are steep-sided and unstable due to the rapid growth of the cone.

Question 26

Slump

Answer 26

Coherent mass of material moving a small distance down a slope leaving behind a scar and concave upward surfaces.

Question 27

Debris slide

Answer 27

Units of surface (Soil, vegetation) slide down a slide on a weakened water-saturated layer

Question 28

Lithology

Answer 28

general physical characteristics of rocks

Question 29

Karst

Answer 29

Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves

Question 30

Concretion

Answer 30

A concretion is a hard, compact mass of matter formed by the precipitation of mineral cement within the spaces between particles, and is found in sedimentary rock or soil. Concretions are often ovoid or spherical in shape,

Question 31

Escarpment/Scarp

Answer 31

An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations. The terms scarp and scarp face are often used interchangeably with escarpment.

Question 32

Dykes

Answer 32

Dykes (or dikes) are igneous rocks that intrude vertically (or across) another land or rock form.

Question 33

Sills

Answer 33

Sills: form when magma intrudes between the rock layers, forming a horizontal or gently-dipping sheet of igneous rock.