Faults And Waves

Question 1

Focus

Answer 1

Initial rupture point along fault underground

Question 2

Dipslip

Answer 2

Vertical movement of fault blocks parallel to fault

Ex. Normal and reverse

Question 3

Normal fault

Answer 3

Hangwall moves down (gravity)
Causes extension/thinning
Divergent boundary

Question 4

Reverse fault

Answer 4

Reverse to gravity
Footwall moves up
Cause compression/thickening
Convergent boundaries

Question 5

Strike slip

Answer 5

Horizontal slip
Hortizonal shear stress
Transform
Ex. Right lateral and left lateral

Question 6

Right lateral

Answer 6

Moves down

Question 7

Left lateral

Answer 7

Moves down

Question 8

Seismic waves

Answer 8

Energy released by break
Stress applied, strain stores, rock break, rebound
Ex. Body and surface waves

Question 9

Body waves

Answer 9

Energy through interior

Ex. P waves and S waves

Question 10

P-waves

Answer 10

Body waves
Moves like slinky= vertical joint
Dialate>compress>dialate
Parallel to wave prop
Travels through outer core liquids solids gas
Faster

Question 11

S waves

Answer 11

Body wave
Shear motion-side to side (lateral sway)
Perpendicular to wave prop
Travels through solids

Question 12

Surface waves

Answer 12

P&S waves combined
Rolling motion
Travels on surface
Arrive after body wave
Ex. Love and Raleigh

Question 13

Raleigh

Answer 13

Vertical and horizontal
Travel through liquid and solid
Slowest

Question 14

What affects shaking and intensity of EQ?

Answer 14

Strength of rock- weak shake more, dense wave speed up, slow energy amplitude increases
Distance to epicenter- further away less shake and low amplitude
Depth of focus- deeper EQ less shake, subduction less shake
Direction of fault rupture
MAGNITUDE ALWAYS THE SAME

Question 15

Foreshocks

Answer 15

Small EQ before main shock

Question 16

Main shock

Answer 16

Largest magnitude

Question 17

Aftershock

Answer 17

Smaller EQ after

Some can be larger magnitude

Question 18

Liquefaction

Answer 18

Wet sediment liquified due to intense shaking

Space between grains fill w water, grains separate during shaking, water squeezed out and gains settle to bottom

Question 19

HAZARDS OF EQ

Answer 19

Fire- broken gas line, power line, oil tanks, electric shorts
Landslides- slopes fall, weak rock, too much weight, loose sediment

Question 20

What will produce a tsunami

Answer 20

EQ at continental collision

Question 21

Waves in open ocean

Answer 21

Barely perceptible

Question 22

Waves enter shallow water

Answer 22

Speed slows
Wave length shorten
Wave height increase- drag against ocean floor cause fast moving waves slow

Question 23

Waves on land

Answer 23

Run up- how far reaches on land
Velocity slows
Water interacts with shoreline and infrastructure
Run up- 30 minutes

Question 24

Effects of run up

Answer 24

Slope of sea floor
Topography of shore
Offshore barriers
Tsunami walls
Character of streets

Question 25

Greatest hazard for tsunami

Answer 25

Subduction zones

Question 26

Tsunami looks like

Answer 26

Sea floor rising
Several waves irregular intervals
First surge not largest
Third wave usually largest

Question 27

Tsunami travel

Answer 27

As far as they want
Wrap around islands
Not necessarily largest near EQ
Size depends on shoreline topography