Earthquakes and tsunamis

Question 1

What is it called when layers of rock bend and crumple without breaking?

Answer 1

It is called folding. Most of the major mountain ranges around the world have been formed in this way.

Question 2

Folds that build upwards are called?

Answer 2

anticlines

Question 3

Folds that build downwards are called?

Answer 3

synclines

Question 4

Once movement occurs along a crack it is called a?

Answer 4

fault

Question 5

If movement along a fault is sideways it is called?

Answer 5

strike-slip

Question 6

What does a fault mean?

Answer 6

A fault is a fracture or zone of fractures between two blocks of rock

Question 7

What is the epicenter of an earthquake?

Answer 7

The epicenter of a earthquake is directly above the point below the surface where the movement in the crust began.

Question 8

The point at which the earthquake begins is called the?

Answer 8

Focus

Question 9

When tremors are sudden and strong they are called?

Answer 9

Earthquakes

Question 10

Where do major earthquakes occur?

Answer 10

They occur at or near where plate boundaries where plates are

Question 11

Define convergent?

Answer 11

Convergent is when the plates are pushing against each other in subduction zones.

Question 12

Define divergent?

Answer 12

Divergent is when the plates are spreading apart to form ocean ridges and new underwater volcanoes or volcanic islands.

Question 13

define transform?

Answer 13

when plates are slipping and sliding against each other in sudden jolts.

Question 14

How are earthquakes measured?

Answer 14

Movements in the earth are recorded with a, seismograph

Question 15

How much does each whole number increasmore energy is released

Question 16

On the Richter scale, How much more energy is being released for each whole number?

Answer 16

32 times more energy

Question 17

What are microquakes?

Answer 17

Earthquakes that measure less than 2.0 on the Richter scale

Question 18

What are seismic waves?

Answer 18

Seismic waves are the waves of energy resulting from the breaking rock that travels through the Earth layer.

Question 19

How are seismic waves measured?

Answer 19

It is recorded on Seismographs

Question 20

What are the two main types of seismic waves?

Answer 20

Body waves and surface waves

Question 21

define body waves?

Answer 21

Body waves can travel through the earths inner layers

Question 22

define surface waves?

Answer 22

surface waves can only move along the surface of the planet like ripples on the water.

Question 23

The destructive power of an earthquake in any location depends on its?

Answer 23

Distance from the epicenter.

Question 24

How fast do Tsunamis travel?

Answer 24

At speeds of 900 km/hour

Question 25

How high can the waves of a tsunami be?

Answer 25

The waves can build to heights of 30-40 m

Question 26

What is a landslide?

Answer 26

A collapse of mass of earth from a mountain or a cliff.

Question 27

What is the ring of fire?

Answer 27

The zone of activity that surrounds the Pacific Ocean and Pacific plate

Question 28

two types of body waves?

Answer 28

○ P waves - compressional, longitudinal waves or
○ S waves - shear, transverse waves.
They both travel through the Earth.

Question 29

What are primary waves?

Answer 29

• P-waves (for primary because they are fastest) and S-waves (for secondary since they are slower).
  
  • P waves travel at speeds between 1 and 14 km/sec, while S waves travel significantly slower, between 1 and 8 km/sec.

Question 30

What are secondary waves?

Answer 30

• S waves are more dangerous than P waves because they have greater amplitude and produce vertical and horizontal motion of the ground surface.
  
  • The slowest waves are surface waves and they arrive last. They travel only along the surface of the Earth.

Question 31

What is a tsunami?

Answer 31

A tsunami is a long, high sea wave (~ 30m) caused by an underwater earthquake, volcanic eruption, avalanche or other disturbance, such as a meteor hitting the Earth.

Question 32

The following diagram below shows how a tsunami is formed. Using appropriate scientific language, explain why the height of a wave increases as it approaches land. What is this process called?

Answer 32

The tsunami moves slower (~40 km/h) in shallow water due to increased frictional forces with the shallower seabed, but still possess the same amount of energy. This means that the wavelength gets shorter (frequency gets bigger) and the amplitude (height of the wave) gets much taller.

Question 33

List TWO warning signs that a tsunami could be approaching a beach.

Answer 33

○ Strong ground shaking from an earthquake,
○ unusual sea-level fluctuations (including the sea suddenly receding - “drawback”),
○ a huge wall of water, and
a loud ocean “roar” (similar to that of a train or jet aircraft).