Topic 1- Hillside Processes

Question 1

what is active tectonics

Answer 1

ongoing deformation

Question 2

isostatic uplift

Answer 2

the release of weight from a tectonic plate causing it to rise
- can be glacial or erosional.

Question 2

what is passive tectonics

Answer 2

indirect influence on process and forms through lithology created by tectonics

Question 3

describe weathering as a geomphic proccess

Answer 3

the disequilibrium response of rock bodies because they are under different temperature and pressure stresses than when they where formed.

Question 4

how does climate effect landscapes? three types of geomorphology

Answer 4

glacial, coastal, fluvial geomorphology

Question 5

why is sand everywhere

Answer 5

its quartz, and its hard to break down

Question 6

what are the two types of hillslopes

Answer 6

transport-limited, and weathering limited hill slopes

Question 7

what is the general shape of a hillslope

Answer 7

convex, straight, concave.
weathering, transport, and depositional dominated.
like a cos wave

Question 8

what are the two forces acting on a slope

Answer 8

driving and resisting

Question 9

Driving & resisting forces are components of what

Answer 9

Fg, The force of gravity

Question 10

what is the equation for Fg

Answer 10

Fg=mg

Question 11

what is the difference between shear strength and resisting forces?

Answer 11

haha tricked you, they are the same!

Question 12

how is Shear strength (S) calculated

Answer 12

Mohr-Coulomb equation:

S = (effective normal stress)Tan (angle of internal friction) + Cohesion

Question 13

define stress

Answer 13

force per area

Question 14

define density

Answer 14

mass per volume

Question 15

what is Normal stress

Answer 15

the stress oriented perpendicular to the slope.

Question 16

what is one way to reduce Normal stress

Answer 16

by any amount of pore water pressure

Question 17

what is pore water pressure

Answer 17

an additional variable that impacts the effective normal stress and is dictated by the height of the water table

Question 18

what is the angle of internal friction

Answer 18

the mechanical resistance to sliding , friction

Question 19

what is the issue with angle of internal friction

Answer 19

it cannot be directly measured

Question 20

what effects the angle of internal friction

Answer 20

grain roundness, grain size, packing , uniformity of grain size

Question 21

how is internal friction quantified

Answer 21

through the angle of internal friction, which is the angle a sediment can hold before failure`

Question 22

what is cohesion

Answer 22

a resisting force that is caused by chemical bonding, and electrostatic attraction.

Question 23

what is cohesion as a variable

Answer 23

alwasy positive

Question 24

what sediments have zero cohesion

Answer 24

all do, only an ideal perfect sand would have zero cohesion

Question 25

what are driving forces

Answer 25

shear stress that is oriented parallel to the slope

Question 26

what is the factor is safety Fs

Answer 26

the ratio between resisting forces and driving forces. AKA shear strength over shear stress.

Question 27

if Fs is 1, >1, <1 what does it mean

Answer 27

balanced, stable, unstable

Question 28

what are the two Types of triggers

Answer 28

External (increase shear stress), and Internal (decrease shear strength) factors

Question 29

what is Rheology

Answer 29

the study of flow and deformation of material under applied forces

Question 30

what are the three types of stresses

Answer 30

tensile(pulling), compressive(crushing), shearing (sliding)

Question 31

what are the three types of rheological responses.

Answer 31

elastic, plastic, and viscous fluid

Question 32

define elastic deformation

Answer 32

returns to the orginal shape after stress is applied

Question 33

define Plastic deformation

Answer 33

does not go back to the original shape after stress is removed

Question 34

define Brittle failure

Answer 34

loss of cohesion, usually occurs at the earths surface

Question 35

define viscosity

Answer 35

internal resistance, that remains constant in newtonian fluids

Question 36

Define Dilatant and Pseudoplastic

Answer 36

shear thickening, vs shear thinning

Question 37

what is liquefaction

Answer 37

loss of soil strength under shocl and leads to fluid behaviour

Question 38

what is Creep

Answer 38

the upward heave with downslope displacement, periodic soul expansion and contraction.

Question 39

mass wasting classification triangle. what are at the three corners

Answer 39

flow, heave, slide.

Question 40

what does the cross section of a slide look like

Answer 40

equal movement at the surface and on the sliding plane

Question 41

what does the cross section of a pure flow look like.

Answer 41

surface flow is faster than bed flow.

Question 42

what does a pure heave cross section look like

Answer 42

Expansion up and Contraction down.

Question 43

what is Debuttressing

Answer 43

cracking occurring in the side of U-shaped valley due to the release of glacial pressure

Question 44

what is a subaqueous landslide

Answer 44

a slide that starts underwater

Question 45

what is a subaerial landslide

Answer 45

A slide that starts above water

Question 46

how do wildfires affect permiability?

Answer 46

reduces, forms water repellant layer