Earthquakes, Their Global Distribution And Their Consequences

Question 1

Define an earthquake.

Answer 1

A shock or series of shocks caused by sudden movements of the Earth’s crust

Question 2

Define the focus of an earthquake.

Answer 2

The point in the Earth’s crust where the earthquake occurs; the origin of seismic energy.

Question 3

Define the epicentre of an earthquake.

Answer 3

The point on the Earth’s surface directly above the focus where an earthquake’s effects are felt first.

Question 4

Define a seismograph.

Answer 4

An instrument that records an earthquake’s shockwaves.

Question 5

Define the Richter Scale.

Answer 5

The chart on which the magnitude of an earthquake is measured.

Question 6

Describe the general global pattern of earthquakes.

Answer 6

Earthquakes are often linear - they are found in lines or zones.
They occur near plate margins.

Question 7

Which places on the Earth are earthquakes mainly found? [3]

Answer 7

1. Around the Pacific Ocean, a part of the ‘Ring of Fire’
2. In a north-south line through the middle of the Atlantic Ocean
3. In an east-west line across southern Europe, the Himalayas and South East Asia.

Question 8

What is the ‘Ring of Fire’?

Answer 8

A major area of the Pacific Ocean where many earthquakes and volcanic eruptions occur.

Question 9

Why do earthquakes occur at plate margins?

Answer 9

This is where friction occurs and pressure builds up as plates move past each other.

Question 10

What are the two main physical consequences of earthquakes?

Answer 10

1. Liquefaction

2. Tsunamis

Question 11

Explain the process of liquefaction. [3]

Answer 11

1. Liquefaction occurs when rock or soil containing water is shaken by an earthquake.
2. This causes the water to rise to the surface and turn the soil into liquid mud.
3. Any buildings resting on the soil collapse.

Question 12

Define a tsunami.

Answer 12

A large wave of seawater caused by an earthquake under the sea.

Question 13

Explain the process of a tsunami. [3]

Answer 13

1. Tsunamis are caused by earthquakes under the sea.
2. Shockwaves from plate movement create small, roughly 30 cm high waves.
3. As the waves move towards the shore and into shallower water, they become much larger, up to 30 m high.

Question 14

How can you tell if a tsunami is approaching without seeing it?

Answer 14

A dramatic fall in sea level can be observed on the shore.

Question 15

Case Study for an MEDC and an LEDC:
1. Causes of earthquakes
2. Impacts of earthquakes
3. Evaluation of the management responses
(MEDC: Kobe, Japan/LEDC: Indian Ocean, Boxing Day, 2004)

Answer 15

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