Earthquakes

Question 1

Earthquakes are a result of?

Answer 1

Plate techtonic motions

Question 2

What causes earthquakes? (4 ways)

Answer 2

Slip along faults(most common)
Change in mineral structure
Movement of magma in a volcano
Volcano Eruption

Question 3

the place where fault slip occurs is called?

Answer 3

A hypocenter

Question 4

How can 3 ways faults react to their environment?

Answer 4

Faults can get reactivated
Faults store and then release energy
Faults move in a stick slip behavior

Question 5

Where do hypocenters occur and how do earthquake waves move?

Answer 5

fault surface, outwards

Question 6

What is the land surface above a hypocenter?

Answer 6

Epicenter

Question 7

What are faults?

Answer 7

like planar breaks in blocks of crust

Question 8

Do most faults have a slope?

Answer 8

Yes (rarely they can be vertical)

Question 9

On a sloping fault, crustal blocks are classified as?

Answer 9

Footwall(block below the fault)
Hanging wall (block above the fault)

Question 10

What is a thrust fault, and where is it found?

Answer 10

A special kind of reverse fault and its found in compressional mountain belts

Question 11

Differentiate between Active and Inactive faults

Answer 11

Active=ongoing stress produces motion
Inactive=motion occurred in the geologic past

Question 12

What does a fault trace show?

Answer 12

fault intersecting the ground

Question 13

Define stick-slip behavior

Answer 13

Stick-friction prevents motion
Slip-friction is briefly overwhelmed by motion

Question 14

How do seismic waves travel?

Answer 14

compressing and expanding material

Question 15

What seismic waves are the fastest?

Answer 15

P waves

Question 16

Where do surface waves travel?

Answer 16

Along the Earth’s exterior

Question 17

What waves are the most destructive?

Answer 17

surface

Question 18

What are L-waves and how do they move?

Answer 18

S-waves that intersect the land surface, move the ground back and forth like a writing snake

Question 19

What are seismographs?

Answer 19

instruments that record ground motion

Question 20

How do seismographs record these motions?

Answer 20

Vertical- records up and down movement
Horizontal-records back and forth movement

Question 21

What order do earthquakes arrive at a station in?

Answer 21

P-waves first, S-waves second, surface waves last

Question 22

How is an earthquake’s size measured?

Answer 22

severity of damage (intensity)
ground motion (magnitude)

Question 23

What is liqueification?

Answer 23

waves occupy H2O filled sediments, causes quicksand to form, reduces friction, unstable land cracks