Tetonic Hazards

Question 1

Define natural hazard

Answer 1

Natural hazards are sudden severe events which make the natural environment difficult to manage.

Question 2

What’s the plate tectonic theory?

Answer 2

• The earths crust is split into seven major and several minor tectonic plates
• There are two types of crust - dense thin oceanic crust and less dense thicker continental crust
• Plates move driven by convection currents within the mantle and under gravity

Question 3

What is ‘hazard risk’?

Answer 3

The chance of being affected by a natural hazard.

Question 3

How does urbanisation affect hazard risk?

Answer 3

Densely populated urban areas concentrate those at risk.

Question 4

How does poverty affect hazard risk?

Answer 4

Expense of housing leads to building on risky ground.

Question 5

How does farming affect hazard risk?

Answer 5

The attraction of nutrient-rich flood plains puts people at risk.

Question 6

How does climate change affect hazard risk?

Answer 6

Global warming raises sea levels and generates more extreme weather.

Question 7

What types of natural hazards are there?

Answer 7

Floods, tropical storms, earthquakes and droughts

Question 8

What are the plate margins called that the earths crust is separated in to?

Answer 8

Constructive, destructive and conservative

Question 9

What happens at a constructive margins?

Answer 9

Plates separate forming new crust causing volcanic eruptions

Question 10

What happens at a destructive palate margin?

Answer 10

Plates collide causing subduction, earthquakes, volcanic eruptions and fold mountains.

Question 11

What happens at a conservative plate margin?

Answer 11

Plates slide past each other causing earthquakes.

Question 12

When did the New Zealand earthquake take place?

Answer 12

February 2011

Question 13

What was the cause of the New Zealand earthquake?

Answer 13

It was a destructive plate margin. Subduction of the Pacific plate beneath the indo Australian plate.

Question 14

What was the size of the NZ earthquake?

Answer 14

7.1 magnitude

Question 15

What we’re the PE of the NZ earthquake?

Answer 15

• 181 killed
• 2000 injured
• Hundreds of kilomètres of damaged sewage pipes and water pipes
• Liquefaction caused lots of damage to roads and buildings
• 80% of the city without electricity

Question 16

What we’re the SE of the NZ earthquake?

Answer 16

• Businesses were out of action for a long period of time causing loss of income
• Schools has to share classrooms due to damage of other school buildings
• Liquefaction made it difficult for people and emergency services to move around
• Christchurch could no longer host rugby matches

Question 17

What were the IR for NZ?

Answer 17

• Cared for the most vulnerable people and ensured people were safe from dangerous buildings
• Chemical toilets were provided for 30,000 residents
• International aid was provided in the form of money (around $6-7 million) and aid workers

Question 18

What were the LTR for NZ?

Answer 18

• Paid $898 million in building claims
• Provided temporary housing and ensured all damaged housing was kept water tight
• Water and sewerage was restored for all residents by August
• Roads and houses were cleared of silt from liquefaction by August and 80% of roads/50% of footpaths were repaired

Question 19

When did the Nepal earthquake take place?

Answer 19

April 2015

Question 20

What was the cause of the Nepal earthquake?

Answer 20

Indo-Australian plate colliding with the Eurasian plate

Question 21

What was the size of the Nepal EQ?

Answer 21

7.9 magnitude

Question 22

What we’re the PE of the Nepal EQ?

Answer 22

• 9000 killed
• 20000 injured
• 8000000 people affected
• widespread destruction of buildings and Infrastructure
• Power water sanitation and communication cut
• $5 billion worth of damage

Question 23

What we’re the SE for this Nepal EQ?

Answer 23

• Communities cut off by landslides and avalanches
• Avalanches on Mount Everest killed at least 19 people
• Flooding caused by blocked rivers

Question 24

What were the IR for the Nepal EQ?

Answer 24

• Overseas aid
• Aid included helicopters for search rescue, supply drops in remote areas such as Mount Everest
• 300 000 migrated from Kathmandu for shelter and support from family and friends

Question 25

What we’re the LTR for the Nepal EQ?

Answer 25

• Roads repaired, landslides cleared and flood lakes drained

* International conference to seek technical and financial support

Question 26

Why do people continue to live at risk from tectonic hazards?

Answer 26

• Some people have no experience or knowledge of the risks
• Poor people have no choice- money, food and family are seen as more important
• Volcanoes can bring benefits such as fertile soils, rich mineral deposits and hot water.

Question 27

How are volcanoes monitored?

Answer 27

• Remote sensing- satellites detect heat increase
• Seismicity - seismographs record microquakes
• Ground deformation- laser beams measure changes in the shape of the ground

Question 28

How are earthquakes monitored?

Answer 28

Earthquake generally occur without warning but a number of events can occur before the quake…
• Microquakes before the main tremor
• Bulging of the ground
• Raised ground water levels

Question 29

How are volcanoes predicted?

Answer 29

Monitoring is now allowing accurate prediction and effective evacuation.

Question 30

How are earthquakes predicted?

Answer 30

Accurate predictions are impossible due to a lack of clear warning signs but historical records can help determine probability.

Question 31

How can protection reduce volcanoes?

Answer 31

Little can be done to protect property but earth embankments and explosives have been used to successfully divert lava flows.

Question 32

How can protection reduce earthquakes?

Answer 32

Earthquake drills help keep people alert and prepared. But earthquake resistant construction is the best way to reduce risk.

Question 33

How can planning reduce earthquakes and volcanoes?

Answer 33

Risk assessment and hazard mapping to identify areas to
• protect buildings and infrastructure
• Practise evacuation or restrict building.