Earthquake

Question 1

Fractures in earth’s surface

Answer 1

Faults

Question 2

Location where slippage begins

Answer 2

Hypocenter or focus

Question 3

Point on Earth’s surface directly above the focus or hypocenter

Answer 3

Epicenter

Question 4

States that large slabs of Earth’s lithosphere are continually grinding past each other

Answer 4

Plate tectonics

Question 5

Earth’s strongest earthquakes most often occur in

Answer 5

Convergent plate boundaries

Question 6

Plate boundary between a subducting slab of oceanic lithosphere and an overlying continental plate

Answer 6

Megathrust fault

Question 7

Faults in which the dominant displacement is horizontal and parallel to the direction of fault trace

Answer 7

Strike-slip faults

Question 8

Instrument that makes a record of seismic waves

Answer 8

Seismograph or seismometer

Question 9

Records obtained from seismograph

Answer 9

Seismogram

Question 10

Earthquakes generate four principal types of elastic waves

• 2
• 2

Answer 10

Body waves - travel within the earth

Surface waves - travel along its surface

Question 11

Body waves are further divided into

Answer 11

P waves (primary waves)
S waves (secondary waves)

Question 12

*back and forth motion in the direction of the path of propagation, stretching or compressing the medium as the wave passes any point

Answer 12

P waves (compressional or longitudinal)

Question 13

*move back and forth perpendicular to the direction of propagation

The medium is sheared first in one direction and then in another

Answer 13

S waves (shear waves)

Question 14

P waves temporarily change the * of material while S waves change the * of the material that transmits them

Answer 14

Volume

Shape

Question 15

• travel faster and it moves the ground from side to side

Displacement of the medium is entirely perpendicular to the direction of propagation and has no vertical or longitudinal components

Produce entirely horizontal motion

Answer 15

Love waves

Question 16

Their motion is a combination of longitudinal compression and dilation that results in an elliptical motion of points on the surface

Rolls the ground: moves the ground up and down and side to side

Answer 16

Rayleigh waves

Question 17

Arrange the waves in order of arrival and increasing amplitude (power/damage)

Answer 17

P - S - Love - Rayleigh

P: 70% faster than S waves
S: 10% faster than surface waves

Question 18

Zone of greatest seismic activity

Answer 18

Circum-Pacific Belt

Question 19

Circumpacific belt encompasses the coastal region of

Answer 19

Chile, Central America, Indonesia, Japan, Alaska

Question 20

Measures the intensity of an earthquake through *

Answer 20

Modified Mercalli Scale

Damage

Question 21

Measures the magnitude of earthquake through *

Answer 21

Richter scale

Energy released

Question 22

Tsunamis are generated by displacement along a * fault that suddenly lifts a large slab of sea floor

Answer 22

Megathrust fault

Question 23

Changes in shape, position, or orientation of a rock mass

Answer 23

Deformation

Question 24

The chemical bonds of the minerals within a rock are stretched but do not break

*first response

Answer 24

Elastic deformation

Question 25

Once the elastic limit (strength) is surpassed, it either flows * or fractures *

Answer 25

Ductile deformation Brittle deformation

Question 26

Rock near the surface where temperatures and confining pressures are low exhibit...

Answer 26

Brittle deformation

Question 27

At depth, where temperatures and confining pressures are high, rocks exhibit...

Answer 27

Ductile deformation

Question 28

Flat-lying sedimentary and volcanic rocks are often bent into a series of wavelike undulations called * Mostly caused by * that result in the shortening and thickening if thrust

Answer 28

Folds Compressional forces

Question 29

Upfold (arrching of sedimentary layers)

Answer 29

Anticlines

Question 30

Downfolds or troughs

Answer 30

Synclines

Question 31

In anticline, * is found in Center In syncline , * is found in center

Answer 31

Oldest strata Youngest

Question 32

Structures with approximately circular or slightly elongate, closed outcrop patterns * convex upward * concave upward

Answer 32

Domes and basins Dome convex Basin concave

Question 33

Large, step-like folds in otherwise horizontal sedimentary strata

Answer 33

Monoclines

Question 34

Upper or overlying block Block below

Answer 34

Hanging wall | Footwall

Question 35

Dipslip faults where the hanging wall block moves down relative to the footwall block

Answer 35

Normal faults

Question 36

A block that has dropped relatively downward between two normal faults dipping toward each other

Answer 36

Graben

Question 37

Block that has been relatively uplifted between two normal faults that dip away from each other

Answer 37

Horst

Question 38

Dipslip faults in which the hanging wall block moves up relative to the footwall block

Answer 38

Reverse fault

Question 39

Normal faults occur in * environments, reverse faults result from strong *

Answer 39

Tensional ~ lengthening Of Earth’s crust Strong compressional forces - shortening or contraction of Earth’s crust

Question 40

Reverse faults that dip less than 45 degrees

Answer 40

Thrust faults

Question 41

Thrust faults with very low angle of dip and very large displacement

Answer 41

Overthrust

Question 42

Fault in which the dominant displacement is horizontal and parallel to the strike of the fault surface *horizontal compression

Answer 42

Strike-slip fault

Question 43

Example of strike slip faut

Answer 43

San Andreas Fault

Question 44

Fractures along which no appreciable displacement has occurred

Answer 44

Joints

Question 45

Mountain building *plate boundary

Answer 45

Orogenesis Convergent

Question 46

Main driving force of orogenesis

Answer 46

Subduction of oceanic lithosphere

Question 47

Oceanic lithosphere subducts beneath an oceanic plate

Answer 47

Volcanic island arc

Question 48

Subduction beneath a continental block

Answer 48

Continental volcanic arc

Question 49

Chaotic accumulation of sedimentary and metamorphic rocks with occasional scraps of ocean crust

Answer 49

Accretionary wedge

Question 50

Relatively small crustal fragment which may be accreted to continents when subduction brings them to trench

Answer 50

Terranez

Question 51

Himalayas and Appalachians were formed by

Answer 51

The collision of landmasses formerly separated by now-subducted ocean basins