Tectonic processes and hazards

Question 1

What is the 3 structures of the earth

Answer 1

The crust
The mantle
The inner and outer core

Question 2

The crust

Answer 2

Varies in thickness (5-10 km beneath the ocean).
1% of Earths total mass.
Made up of several major plates

Question 3

The mantle

Answer 3

Widest layer (2900km thick)
Heat and pressure makes rock liquid state

Question 4

The inner and outer core

Answer 4

Hottest section (5000 degrees)
Mostly made of iron and nickel and is 4x denser than the crust.
Inner layer solid, outer layer liquid

Question 5

What is a tectonic plate

Answer 5

A massive, irregularly shaped slab of solid rock, composed of both continental and oceanic lithospheres. Tectonic plates move in various ways against each other (plate margins)

Question 6

What is slab pull

Answer 6

When older, denser tectonic played dunk into the mantle at subduction zones

Question 7

What is ridge push

Answer 7

Gravitational force that causes a plate to move away from the crest of an ocean ridge, and into a subduction zone

Question 8

Earthquake secondary effects

Answer 8

Liquefaction
Landslides and avalanches
Tsunamis

Question 9

What is liquefaction

Answer 9

Solid material changed into a liquid state. Damage to building foundations, results in them sinking

Question 10

How can earthquakes cause landslides and avalanches

Answer 10

Earthquakes in mountainous regions often cause landslides and avalanches. Steep, unstable slopes are notoriously unstable and vulnerable to landslides

Question 11

How can earthquakes create tsunamis

Answer 11

Earthquakes occurring underwater can cause the seabed to rise, leading to the displacement of water, producing powerful waves which spread out from the epicentre

Question 12

What is the epicentre of an earthquake

Answer 12

Point on the earths surface vertically above the focus in the crust where the earthquake begins

Question 13

What is lahar

Answer 13

Volcanic mudflow which usually runs down a valley side on the volcano

Question 14

What is pyroclastic flow

Answer 14

Fast moving current of super heated gas and ash (1000°C) Travels at 450 mph

Question 15

What is an ash cloud

Answer 15

Small pieces of pulverised rock and glass which are thrown into the atmosphere

Question 16

What was the magnitude of the Haiti earthquake

Answer 16

7.0

Question 17

Where was the Haiti earthquake

Answer 17

15 miles of capital Port au Prince

Question 18

Short term effects of Haiti earthquake

Answer 18

230,000 people died and 3 million effected
250,000 homes and 30,000 collapsed or damaged
Rubble blocked roads and ports

Question 19

Long term effects of Haiti earthquakes

Answer 19

• 1 in 5 jobs lost
• Millions homeless
• Disease spread became big due to sanitation damage and corpse unburied

Question 20

Immediate management of Haiti earthquake

Answer 20

• People tried to recover buildings and people

- Many countries responded with appeal and rescue teams

Question 21

Long term management of Haiti earthquake

Answer 21

• International aid e.g $330 million from EU

- 6 months after, 98% rubble still remained

Question 22

What is the richter scale

Answer 22

Measures earthquakes magnitude

Question 23

How can you predict an earthquake

Answer 23

Scientists can reuse where earthquakes happen but not when
Examples:
Satellite surveying (tracks changes in earths surface)
Water table level (water levels fluctuate before an earthquake)
Radon gas sensor (Radon gas is released when plates move so this finds that)

Question 24

How can you prepare for an earthquake

Answer 24

Training for emergency services
Practising earthquake drills
Emergency kits that include first aid items, blankets and tin food

Question 25

How can you protect from earthquake

Answer 25

Building aseismic buildings
Raising public awareness
Improving earthquake prediction

Question 26

How to predict a tsunami

Answer 26

No way of predicting ‘tsunami-causing earthquake’

Early warning systems can get word out of approaching tsunami

Question 27

How to prepare for a tsunami

Answer 27

Evacuation routes on coastlines indicated by signs and signalled by sirens
DART ( Deep-ocean assessment and reporting of Tsunami) sea floor sensors can monitor passing tsunamis

Question 28

How to protect from tsunami

Answer 28

Building designed with raised, open foundations and made of strong materials such as concrete
Tsunami walls have been built around settlements to protect them

Question 29

How to predict volcanic eruptions

Answer 29

Seismometers to detect earthquakes
Thermal imaging can be used to detect heat around volcano
Gas samples may be taken and chemical sensors used to measure sulphur levels

Question 30

Preparation for volcanic eruption

Answer 30

Exclusion zone around volcano
Emergency kit of key supplies
Evacuation routes
Trained emergency service ms with good communication systems

Question 31

How are Divergent/Constructive Plate Boundaries formed

Answer 31

Caused by geologically recent mantle plume splitting a continental plate to create a new ocean basin. It can cause Basaltic volcanoes and minor earthquakes.

Question 32

How is a Conservative Plate Boundary formed

Answer 32

Two plates slide past each other in either different directions or the same direction but at different speeds. As they shear past they can cause powerful earthquakes.

Question 33

Formula for risk

Answer 33

Risk = hazard x exposure x vulnerability/manageability

Question 34

When was the haiti earthquake

Answer 34

12 January 2010

Question 35

Why is Unpredictability a risk

Answer 35

many hazards are not predictable and people can be caught out by timing or magnitude.

Question 36

What is Dynamic Hazards

Answer 36

the threat from hazards fluctuates and human influence

can play a role.

Question 37

What is cost-benefit

Answer 37

the benefit of staying in a hazardous location may outweigh the risk (perception of risk plays a role
here)

Question 38

What is russian roulette reaction

Answer 38

the acceptance of the risk as something that will happen whatever you do, that is, one of fatalism.

Question 39

What does deggs model show

Answer 39

shows that a natural disaster only occurs if a vulnerable population is exposed to a hazard.