Hazards - Seismic

Question 1

How can scientists predict earthqaukes? (2)

Answer 1

1 - Measure changes in the shape of the earthquake

2 - Monitor tiny earthquakes

Question 2

What are the primary effects?

Answer 2

Effects that are a direct result of the hazard

Question 3

What are secondary effects?

Answer 3

Impacts that are caused by primary impacts

Question 4

What are the social impacts of seismc hazards? (3)

Answer 4

1 - Building damage - homelessness

2 - Rupture gas pipes and break power lines leading to fires

3 - Tsunamis flood large areas - destroy crops, kill people

Question 5

What are the environmental impacts of seismic hazards? (3)

Answer 5

1 - Damaged power plants leak toxic chemicals

2 - Fires

3 - Water salinised by tsunamis

Question 6

What are the political impacts of seismic hazards? (3)

Answer 6

1 - Lack of food and water cancause conflict and unrest

2 - Countries development stunted as money put aside to spend on development was spent on repairing damage

3 - Money may need to be borrowed putting causing debt

Question 7

What are the economic impacts of seismic hazards? (3)

Answer 7

1 - Ground shaking and liquedaction destroy shops

2 - Damage to industry could lead to country relting on expensive imports of goods

3 - Damage expensive to repair

Question 8

What is liquefaction?

Answer 8

Ground shakes so much that it becomes soft

Question 9

How can the effecyts of seismic hazards be prevented? (2)

Answer 9

1 - Prevent land that is prone to liquefaction being built on

2 - Build sea walls to prevent tsuamis hitting land

Question 10

How can the effects of a seismic hazard be prepared against? (4)

Answer 10

1 - Earthquake warning systems via TV, radio

2 - Staying away from buildings, using desk as shelter

3 - Evacuation routes signposted

4 - Search and rescue teams + Fire response units

Question 11

How can people adapt to mitigate againts seismic risks? (2)

Answer 11

1 - Buidlings designed to sway rather than break by using flexible materials

2 - Tall and strong buildings protect from tsunamis

Question 12

How many deaths have been attributed to stroms in the last 200 years?

Answer 12

1.9 mil - 10,000 per year

Question 13

What are the two types of Body waves?

Answer 13

1 - Primary 2 - Secondary

Question 14

What are the two types of surface waves?

Answer 14

1 - L waves 2 - R waves

Question 15

Describe the process of an earthquake? (5)

Answer 15

1 - Plates jerk past eachother which builds up pressure

2 - When this pressure is released it sends out shockwaves which are the earthquake

3 - The shockwaves spread out from the focus. The nearer the focus the waves are stronger and cause more damage

4 - The epicentre the earths surface directly above the focus so is where the earthquake is felt first

5 - Eathquakes cause the ground to shake and rupture

Question 16

What are the three scales which are used to measure an earthquake? (3)

Answer 16

1 - Richter scale - measures the magnitude

2 - Moment magnitude scale (MMS) - Measures energy released by an earthuquake

3 - Mercalli scale - Measures the impacts of an earthquake

Question 17

Which scale is more accurate, Richter or MMS?

Answer 17

MMS so is more widely used

Question 18

Descirbe the process of a tsunami? (2)

Answer 18

1 - An underwater earthquake causes the sea bed to move which displaces large volumes of water

2 - The greater the movement of the sea bed the more water displaced and the bigger the wave from the epicentre

Question 19

What are the features of a tsunami? (2)

Answer 19

1 - Tsuanmis that start near the coast are more powerful because the waves lose less energy as they travel towards land

2 - The waves travel very fast so hit the shore with little warning - high death toll

Question 20

How are Avalances and Landslides caused? (2)

Answer 20

1 - Shaking of the ground dislodges rock/soil/snow which can cause landslide or avalanches which quickly move downslope

2 - The shaking can lossen ground material which means more water infiltrates. The extra water weight can cause a landslide even after the earthquake has stopped

Question 21

How does soil liquefaction occur? (2)

Answer 21

1 - When soil is saturated with water the vibrations of an eathquake can cause it to act like fluid

2 - This makes the soil weaker and easier to deform. This makes it more likely to collapse where it has a heavy wight on top of it

Question 22

How does margin type affect an earthquake? (2)

Answer 22

1 - Earthquakes at destructive plate margins have a higher magnitude than earthquakes at constructive plate margins

2 - This is because the subduction of the plate at a destructive margin causes lots of pressure to build up leading to a huge erathquake when this is released

Question 23

How does the depth of the focus affect an earthquake? (2)

Answer 23

1 - Deep focus earthquakes have higher magnitudes than shallow focus earthquakes

2 - Deep focus earthquakes however cause less damage that shallow earthquakes because the shock waves have to travel further to reach the surface which reduces their power

Question 24

Do seismic hazards follow a pattern?

Answer 24

No they are random

Question 25

How can scientists predict seismic hazards?

Answer 25

They can monitor the movement of tectonic plates to predict which areas are at high risk but can’t predict when the earthquake will strike or it’s magnitude

Question 26

What are body waves?

Answer 26

Waves that travel through the earth

Question 27

What are surface waves?

Answer 27

Waves that travel on the earths surface

Question 28

What are body waves?

Answer 28

Waves that travel through the earth

Question 29

What are surface waves?

Answer 29

Waves that travel on the earths surface