Chapter 2

Question 0

Stress

Answer 0

Force exerted when an object presses on, pulls on, or pushes against another object

Question 1

Fault

Answer 1

Fracture or break in Earth’s lithosphere where blocks of rock move past eachother

Question 2

Earthquake

Answer 2

Shaking of the ground caused by a sudden movement of large blocks along a fault

Question 3

What is the direction of a strike slip fault?

Answer 3

Scrape past eachother in opposite directions

Question 4

Strike slip fault

Answer 4

Moves horizontally
Like transform
Shallow earthquake

Question 5

Normal fault

Answer 5

Moves apart
Like divergent
Moves vertically
Shallow and intermediate earthquakes

Question 6

Reverse fault

Answer 6

Pushes together
Like convergent
Moves vertically
All types of earthquakes

Question 7

Where are most earthquakes common?

Answer 7

Near places with big populations, along tectonic plate boundaries

Question 8

Why do most earthquakes occur at tectonic plate boundaries?

Answer 8

That’s where faults are located

Question 9

Seismic waves

Answer 9

Vibrations caused by an earthquake, how energy travels

Question 10

Focus

Answer 10

Point underground where rocks first begin to move

Question 11

Epicenter

Answer 11

Point on Earth’s surface directly above the focus

Question 12

Seismograph

Answer 12

Instrument that records ground movement

Question 13

Seismogram

Answer 13

The record made by a seismograph in response to ground motions

Question 14

P wave

Answer 14

Primary wave
Goes in a straight line
Arrives first
Push and pull movement

Question 15

S wave

Answer 15

Secondary wave
Up and down movement
Arrives second
Goes in a zig zag motion

Question 16

Surface waves

Answer 16

Arrive last
On the surface
Waves move up and down like S wave

Question 17

How are shallow focuses different from deep focuses?

Answer 17

A shallow focus causes more damage because it’s closer to the land.

Question 18

Which waves are the most powerful?

Answer 18

Surface

Question 19

What do the wiggles on a seismogram indicate?

Answer 19

How powerful the earthquake was

Question 20

What can scientists learn from studying seismograms?

Answer 20

The location and strength

Question 21

How many different seismic stations are needed to locate the epicenter?

Answer 21

3 each station must determine the distance of the earthquake

Question 22

Seismic gap

Answer 22

A segment of an active fault known to produce significant earthquakes

Question 23

Aftershock

Answer 23

A smaller earthquake that follows a more powerful one in the same area

Question 24

Liquefaction

Answer 24

Where shaking of the ground causes soil to act like a liquid

Question 25

Tsunami

Answer 25

Giant water wave triggered by an earthquake, volcanic eruption, or landslide

Question 26

Name four damages done by earthquakes

Answer 26

``` Fires Landslides Tsunamis Aftershocks Liquefaction Avalanche ```

Question 27

What are the two types of magnitude scales?

Answer 27

Richter scales calculate how fast the ground moves at a seismic station Moment magnitude scales were used before Richter scales were invented. They can measure the strength

Question 28

When are earthquakes most dangerous?

Answer 28

When they occur where a lot of people live

Question 29

As a tsunami reaches shallower water around an island or continent what happens?

Answer 29

The tsunami slows when water gets shallower. The water level rises.

Question 30

Why do the areas with the most risk are close together instead of spread out?

Answer 30

They're by the same active fault

Question 31

What are earthquake resistant methods?

Answer 31

``` Shear walls Shear core Base isolator Moat Cross braces ```

Question 32

Base isolators do what?

Answer 32

Absorb the ground motion

Question 33

Moats do what

Answer 33

Let the building shake more gently

Question 34

Shear walls and core

Answer 34

Stop the walls from shaking and add strength to it

Question 35

Cross braces

Answer 35

They help the structure keep its shape while being shaken

Question 36

A subduction zone is which type of fault?

Answer 36

Reverse

Question 37

Three characteristics of tsunamis

Answer 37

Tall Dangerous Powerful Fast

Question 38

What can scientists predict about earthquakes?

Answer 38

Risk in an area

Question 39

Why can't scientists predict earthquakes?

Answer 39

They don't know exactly when it's going to happen