Seismicity

Question 1

What is seismicity? (seismicity tectonics)

Answer 1

The phenomenon of earthquake activity

Question 2

What is an earthquake? (seismicity tectonics)

Answer 2

The sudden release of energy that creates seismic waves that read out spherically

Question 3

Where do earthquakes tend to occur? (seismicity tectonics)

Answer 3

Conservative (but can occur on any place margin)

Question 4

What is the epicentre? (seismicity tectonics)

Answer 4

The point on the Earth’s surface directly about the focus

Question 5

What is the focus point? (seismicity tectonics)

Answer 5

The point in the ground where pressure is released

Question 6

What are the three types of focus point? (seismicity tectonics)

Answer 6

• Shallow focus
• Intermediate focus
• Deep focus

Question 7

What is the depth and damage of a shallow focus? (seismicity tectonics)

Answer 7

0-70km

greatest damage, releasing 75% of energy

Question 8

What is the depth and damage of an intermediate focus? (seismicity tectonics)

Answer 8

70-300km

Moderate damage

Question 9

What is the depth and damage of a deep focus? (seismicity tectonics)

Answer 9

300-700km

Minimal damage

Question 10

What are some of the factors that the impact of an earthquake is dependent on? (seismicity tectonics)

Answer 10

Focus
Strength
Time
Rock type
Development
Land use

Question 11

If a primary effect is the ground shaking leading to collapse of infrastructure, what is the secondary and long term effects of this? (seismicity tectonics)

Answer 11

• Fires
• Deaths
• Disease
• High unemployment
• Homelessness

Question 12

If a primary effect is schools being destroyed, what is the secondary and long term effects of this? (seismicity tectonics)

Answer 12

suspended education leading to a lost generation

Question 13

If a primary effect is homelessness and starvation, what is the secondary and long term effects of this? (seismicity tectonics)

Answer 13

NGO’s provide tents, food and water which may become a long term issue

Question 14

What are P-waves? (seismicity tectonics)

Answer 14

• Primary waves
• Compressional
• Fastest wave
• Travels through any solid
• In the air, takes the form of a sound wave

Question 15

What are S-waves? (seismicity tectonics)

Answer 15

• Secondary waves
• Transverse (ground is displaced perpendicularly to the movement)
• Will only travel through solids
• Medium speed and relatively destructive

Question 16

What are Surface waves? (seismicity tectonics)

Answer 16

• Travels near to the surface
• Slowest and most destructive wave
• Long waves cause the ground to move sideways

Question 17

How does the Mercalli scale work? (seismicity tectonics)

Answer 17

Measures the amount of damage caused by an earthquake and uses descriptions of damage and photos to describe the intensity

Question 18

According to the Mercalli scale, what is the description and observation of a level 1 earthquake? (seismicity tectonics)

Answer 18

instrumental - only detected by seismographs

Question 19

According to the Mercalli scale, what is the description and observation of a level 6 earthquake? (seismicity tectonics)

Answer 19

Strong - trees sway and some damage is caused

Question 20

According to the Mercalli scale, what is the description and observation of a level 12 earthquake? (seismicity tectonics)

Answer 20

Catastrophic - total destruction

Question 21

How does the Richter scale work? (seismicity tectonics)

Answer 21

Measures the amount of seismic energy released by the earthquake, using a seismography to record the amount of energy realised on a scale of 1-9

Question 22

According to the Richter scale, what is the description of a 0-2 earthquake? (seismicity tectonics)

Answer 22

Not felt by anyone

Question 23

According to the Richter scale, what is the description of a 5-6 earthquake? (seismicity tectonics)

Answer 23

furniture will move

Question 24

According to the Richter scale, what is the description of a 8-9 earthquake? (seismicity tectonics)

Answer 24

total destruction