Chapters 7 - 9

Question 1

Geothermal Gradient

Answer 1

Earth’ temperature increase with depth

Question 2

Deformation

Answer 2

Change in shape or volume or both of rocks in response to stress

Question 3

P Wave Shadow Zone

Answer 3

103 degrees - 143 degrees from earthquake

Question 4

S Wave Shadow Zone

Answer 4

103 degrees + from earthquake focus where no s-waves were recorded.

Question 5

Discontinuity

Answer 5

A boundary across which seismic wave velocity o direction of travel changes abruptly, such as the mantle-core boundary.

Question 6

Moho

Answer 6

Boundary between Earth’s crust and mantle

Question 7

Intensity

Answer 7

Subjective measure of kind of damage done by earthquakes and peoples reaction to it.

Question 8

Magnitude

Answer 8

The total amount of energy released by an earthquake at its source

Question 9

Modified Mercalli Intensity Scale

Answer 9

A scale w/ values from 1 to XII used to characterize earthquakes based on damage.

Question 10

Richter Magnitude Scale

Answer 10

An open-ended scale that measures the amount of energy released during an earthquake

Question 11

R-Wave

Answer 11

Elliptical path within a vertical plane

Question 12

L-Wave

Answer 12

Move only back and forth in a horizontal plane

Question 13

P-Wave

Answer 13

Push-pull wave (primary) fastest wave

Question 14

S-Wave

Answer 14

Moves perpendicular to the direction of travel (secondary)

Question 15

Lithostatic Pressure

Answer 15

Pressure exerted on rocks by weight of overlaying rocks

Question 16

Differential Pressure

Answer 16

Pressure that is not applied equally to all sides of a rock

Question 17

3 Main types of metamorphism

Answer 17

Contact - Country Rock adjacent to a platon

Dynamic - In fault zones where rocks are subject to differential pressure

Regional - Occur over a large area

Question 18

Stress

Answer 18

force per unit applied to a material such as a rock

Question 19

Strain

Answer 19

deformation caused by stress

Question 20

Compression

Answer 20

Stress resulting when materials are squeezed by external forces directed toward one another

Question 21

Tension

Answer 21

Stress where forces act in opposite directions but along the same line, thus tending to stretch an object

Question 22

Shear Stress

Answer 22

forces acting parallel to one another but in opposite directions; results in deformation by displacement of adjacent layers along closely spaced planes.

Question 23

Elastic Stress

Answer 23

Type of deformation in which the material returns to its original shape when stress is relaxed

Question 24

Plastic Stress

Answer 24

Permanent deformation of a solid with no failure by fracturing

Question 25

Fracture

Answer 25

A break in rock resulting from intense applied pressure.

Question 26

Strike

Answer 26

The direction of a line formed by the intersection of an inclined plane and a horizontal plane

Question 27

Dip

Answer 27

A measure of the maximum angular deviation of an inclined plane from horizontal

Question 28

Geologic Structure

Answer 28

Any feature in rocks that results from deformation, such as folds, joints, and faults.

Question 29

Fold

Answer 29

A type of geologic structure in which planar features in rock layers such as bedding and foliation have been bent

Question 30

Monocline

Answer 30

A bend or flexure in otherwise horizontal or uniformly dipping rock layers.

Question 31

Anticline

Answer 31

A convex upward fold in which the oldest exposed rocks coincide with the fold axis all strata dip away from the axis

Question 32

Syncline

Answer 32

A down-arched fold in which the youngest exposed rocks coincide with the fold axis and all strata dip toward the axis

Question 33

Dome

Answer 33

A rather circular geologic structure in which all rock layers dip away from a central point and the oldest exposed rocks are un the dome's center

Question 34

Basin

Answer 34

A circular fold in which all strata dip inward toward a central point and the youngest exposed strata are in the center

Question 35

Joint

Answer 35

A fracture along which no movement has occurred or where movement is perpendicular to the fracture surface

Question 36

Fault

Answer 36

A fracture along which rocks on opposite sides of the fracture have moved parallel with the fracture surface

Question 37

Fault plane

Answer 37

A fault surface that is more or less planar

Question 38

Hanging wall block

Answer 38

The block of rock that overlies a fault plane

Question 39

Footwall Block

Answer 39

The block of rock that lies beneath a fault plane

Question 40

Dip-slip fault

Answer 40

A fault on which all movement is parallel with the dip of the fault plane

Question 41

Normal Fault

Answer 41

A dip-slip fault on which the hanging wall block has moved downward relative to the footwall block

Question 42

Reverse fault

Answer 42

A dip-slip fault on which the hanging wall block has moved upward relative to the footwall block

Question 43

Thrust fault

Answer 43

A type of reverse fault in which a fault plane dips less than 45 degrees

Question 44

Strike-slip fault

Answer 44

A fault involving horizontal movement of blocks of rock on opposite sides of a fault plane

Question 45

Oblique-slip fault

Answer 45

A fault showing both dip-slip & strike-slip movement

Question 46

Orogeny

Answer 46

An episode of mountain building involving deformation, usually accompanied by igneous activity, and crustal thickening

Question 47

Continental Accretion

Answer 47

Orogenics along convergent plate boundaries that result in adding material to a continent

Question 48

Terrane

Answer 48

Fragments of seamounts, island arcs, & small pieces of continents that were carried on oceanic plates that collided with continental plates

Question 49

Principle of isostasy

Answer 49

The concept of Earth's "floating" on a dense underlying layer.

Question 50

isostatic rebound

Answer 50

The phenomenon in which unloading of the crust causes it to rise until it attains equilibrium