Tectonic & Climatic hazards Flashcards

1
Q

Plate Boundaries

A

Constructive
Conservative
Destructive
Collision

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2
Q

Definition of a natural hazards

A

A natural hazard is an extreme natural event or process that causes loss of life and/or extreme damage to property and creates severe disruption to human activities

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3
Q

Conservative/Transform plate boundary

A

Plates slide past each other
Causes pressure + stress to build up
A quick release of energy causes sudden movements which create earthquakes

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4
Q

Constructive plate boundary

A

Caused by convectional currents in the mantle
Plates move away from each other
Magma then rises and causes volcanic eruptions

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5
Q

Destructive plate boundary

A

Convectional currents in mantle
Oceanic & continental plates move together
Pressure builds up and the thinner oceanic plate gets subducted and melts
Causes volcanic eruptions as magma then rises

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6
Q

Collision plate boundaries

A

Convectional currents in the mantle
2 continental plates of the same density and strength move towards each other
Pressure builds up causing buckling to form mountains + volcanoes

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7
Q

How to predict volcanic eruptions

A

Gas measurements - SO2 & CO2 levels increase
Seismic readings
Satellite imagery - measures ‘bulges’ as magma moves up the volcanoes
Temperature/acidity of soil - increases

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8
Q

Causes of Nevada del Ruiz - Colombia

A
Dormant for 150 years
Destructive Plate Boundary 
Nazca plate (oceanic) subducted under south American plate (continental)
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9
Q

Effects of Nevada del Ruiz - Colombia

A

Pyroclastic flow (20 m. cubic metres of hot ash, rock +gas)
Lava flows
Huge Lahar (40m thick + moved at 50 km/h)
23,00 deaths
5000 injured
5000 homes destroyed

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10
Q

Secondary effects of Nevada del Ruiz - Colombia

A

Hot lahars served as breeding ground for bacteria + many with minor cuts got infected & died
Blocked roads and people couldn’t be reached
Cost Colombia 20% of their GDP (7.7 bil.)

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11
Q

Responses to Nevada del Ruiz- Colombia

A

No evacuation
Inadequate rescue + emergency services
Locals had ignored warnings from American volcanologists ( no Colombian equipment)

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12
Q

Why there were inadequate response

A

LEDC
During the night ( hard rescue)
Large population
Roads + bridges destroyed

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13
Q

Causes of Mount Etna - Italy (2002)

A

Strato volcano
Destructive plate boundary
African plate slipped under Eurasian

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14
Q

Effects of Mount Etna - Italy (2002)

A
1,000 people evacuated 
100 homes destroyed
Forests destroyed
Tourism effected
2 channels dug to divert lava
Tax breaks for villagers
$8 m. Given to the town
Loss of agricultural land 
Columns of ash deposited material in Libya
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15
Q

Formation of Hurricane Katrina

A

Formed in the Gulf of Mexico off the coast of Florida in August 2005

27*C
60m deep
Convection
Circular pattern - rotation of Earth

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16
Q

Before Hurricane Katrina

A

Satellite monitoring
400 army reserves
State of emergency called
1.2 mill. were issued with evacuation orders
57 emergency shelters set up e.g. Louisiana SuperDome
Levees built

17
Q

Impacts of Hurricane Katrina

A
Levees breached in 53 different places
80% of city flooded 
3m deep flooding
1,836 deaths 
10,000 homeless
Food & clean water shortages
18
Q

Failures of Hurricane Katrina

A

Levees not high or strong enough for category 5

Not enough transport to evacuate all

19
Q

Cyclone Nargis - Myanmar 208

A
SE asia 
Population - 55 mill.
LEDC
GDP per capita - £1900
1/1000 have internet
32/50 poorest countries
20
Q

Causes of Cyclone Nargis - Myanmar 2008

A

Mangrove forests cut down for farming and tourism
Low lying land
Shallow continental shelf
No defences, no prediction, no evacuation
(Government refused help from foreign countries)

21
Q

Impacts of Cyclone Nargis - Myanmar 2008

A
1.5 mill. severly effected 
over 15,000 deaths
95% buildings destroyed
Millions left homeless
Sewage systems damaged - disease 
Crops destroyed - hunger, loss of income 
Electricity cut off
Roads swept away
Mosquitos - disease
22
Q

Why the responses were so bad in Myanmar 2008

A

Poor responses - LEDC
No evacuation
Military government didn’t allow help in from abroad

23
Q

Benefits of volcanic eruptions

A
Fertile soil
Minerals
Sulphur Mining
Dramatic scenery attracts tourists
Generates geothermal energy
24
Q

Ways earthquakes are measured

A

Richter scale - measures magnitude of an earthquake (strength of shaking)
Mercalli scale - measures the damage caused by an earthquake

25
Q

Different types of tropical storms

A

Hurricanes
Cyclones
Typhoons

26
Q

Tropical storms

A

Intense, low pressure systems (depressions)

27
Q

Factors needed for tropical storms to form

A

Ocean water at least 27oC
Water at least 60m deep
Between the tropics of cancer and Capricorn
Low air pressure

28
Q

Names of plates

A
Eurasian 
Indo-Australia
Nazca
Pacific
Antarctic
North America
South America
29
Q

Advantages of living in the tropics

A
Climate for growing crops 
Fishing 
Natural area 
Tourist industry 
Exotic fruit & fish