Mass Movements Flashcards

(33 cards)

1
Q

Free fall

A
  • Material detaches from a slope and then free falls through the air, or bounces and rolls downslope
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2
Q

Slide

A
  • Material (either rock or regality) that slides along a surface of rupture
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3
Q

Flow

A

Continuous movement of rock, regolith, or both that behaves as a high viscosity liquid

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4
Q

Rock falls are…

A

extremely rapid

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5
Q

Debris/earth falls are..

A

Rapid to extremely rapid

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6
Q

Rock slides are…

A

Very slow to extremely rapid

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7
Q

Debris/earth slides are…

A

Very slow to very rapid

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8
Q

Rock slumps are…

A

Extremely slow to moderate

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9
Q

Debris/earth slumps are…

A

Very slow to very rapid

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10
Q

Distinguishing the speed of motion:

A
  • Slow (cree
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11
Q

What factors make up the criteria for the classification scheme or mass movements?

A
  • Nature of the mixture of solids (rock, debris, or earth materials)
  • Type of motion (fall, slide or flow)
  • Velocity of motion (avalanche, flow, or creep)
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12
Q

Creep

A

Is slow and only detected by dislocation or bending of features at the surface

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13
Q

Debris Avalanches:

A

Are very rapid flows of rock, regolith, vegetation and/or sometimes ice

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14
Q

Flow

A

Are the continuous movements of rock, regolith, or both which behaves like a high viscosity liquid. Flow occurs on different scales

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15
Q

Rock creep:

A

Is extremely slow to slow (slow flows)

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16
Q

Debris/earth creep:

A

Is extremely slow to slow

17
Q

Debris/earth flow:

A

Is very rapid

18
Q

Debris avalanche (rock and regolith):

A

Is very rapid to extremely rapid

19
Q

When are rock falls common?

A

They are common where rock is highly jointed and on a steep slope

20
Q

Talus

A

Is the loose material that piles up at the base of steep slopes. Lack of vegetation/soil on talus indicates that material is actively accumulating

21
Q

Planar slides:

A

Move downslope in contact with a surface of rupture, typically along bedding planes, foliation, or joint planes oriented parallel to the slope

22
Q

Slump:

A

Is the curved rotational slide surfaces that are scoop shaped and usually form in regolith, poorly consolidated, or weak rock where bedding/joints do not influence failure

23
Q

What forces AFFECT slope stability?

A
  • Gravity force
  • Friction
  • Cohesion
24
Q

Gravity force:

A

In order for motion to happen, the gravity force parallel to the surface must be greater than the resisting strength

25
Friction
Is the force that opposes motion between two objects that are touching one another -
26
What increases friction?
More roughness = more friction
27
Cohesion
Is the attraction of particles at the atomic level
28
What has little cohesion?
Loose sand and gravel
29
What factors DETERMINE slope stability
Angle of repose | Vegetation
30
Angle of repose
The maximum angle of stability at which no movement occurs as determined by the friction, cohesion, and particle shape
31
Vegetation
Is very important as roots penetrate and bind together regolith and absorbs water from precipitation
32
Arid Climates
Have low vegetation abundance and slow rates of weathering and surface water removes most regolith particles very quickly as they loosen from bedrock
33
Angle of sliding friction
The angle at which the particles start to slide