Hazardous Environments Flashcards
1
Q
Tropical Cyclones
A
- known as hurricanes, cyclones, typhoons in different areas
- heavy rainfall, high wind speeds, high waves and storm surges
- measured from 1-5 on Saffir-Simpson scale
2
Q
Earthquakes
A
- sudden and violent shaking of the ground
- occur at all plate boundaries, result of immense pressure buildup
- epicentre is directly above focus on the earth’s surface
- focus is where the earthquake originates below ground
- measured using MM scale or Richter scale
3
Q
Volcanoes
A
- occur at constructive and destructive plate boundaries
- a location where magma erupts onto the earth’s surface as lava
- ## measured using VEI (Volcanic Explosivity Index)
4
Q
Tropical Cyclone Formation
A
- 27C sea surface temperature
- between 5-20 of the Equator
- warm air rises rapidly, while air from high pressure areas moves to fill the place of the rising air
- this air rises, forming a flow of continuous air
- air condenses, releasing heat energy, which helps to power the storm
- Coriolis force causes the rising air to spiral around the centre
- moves westwards
5
Q
Constructive (Divergent) Plate Boundary
A
- plates move apart in opposing directions
- volcanoes and earthquakes
- e.g. Mid-Atlantic Ridge
6
Q
Destructive (Convergent) Plate Boundary
A
- plates move towards each other
- denser/heavier oceanic plate subducts under the lighter continental plate
- Volcanoes + Earthquakes
7
Q
Collision Boundary
A
- two plates of similar density move towards each other
- neither subducts, instead land is pushed upwards
- this process forms fold mountains such as the Himalayas
- earthquakes
8
Q
Conservative (Transformative) Boundary
A
- plates move past each other in opposing directions or in the same direction at different speeds
- earthquakes
9
Q
Volcano Formation
A
- Constructive - lave escapes through gap left as plates move apart, the lava cools and hardens forming new crust, forms shield volcanoes
- Destructive - oceanic plate subducts, plates come together causing friction, the generated heat melts the crust, allows magma to rise to the surface, forms strato volcanoes
10
Q
Volcano - Primary Hazards
A
- Ash
- Pyroclastic Flow
- Lava Flow
- Gas Emissions
- Volcanic Bombs
11
Q
Volcanoes - Secondary Hazards
A
- Lahars
- Acidification
- Landslides
- Climate Change
- Fires
- Floods
12
Q
Earthquakes - Primary Hazards
A
- ground shaking
13
Q
Earthquakes - Secondary Hazards
A
- Collapse of buildings and other structures
- Landslides
- Gas leaks
- Fires
- Soil liquefaction
- Subsidence
- Mudflows
- Tsunami
14
Q
Earthquake Formation
A
- as tectonic plates move, they get stuck
- pressure builds as the plates try to move past each other
- eventually the plates slip past each other and the built up pressure is released as energy
15
Q
Reasons for living in hazardous areas
A
- lack of education means that people are not aware of the risks
- many advantages - fertile soil, geothermal energy, access to water, trade,jobs, tourism
- too impoverished to relocate
- due to infrequent disasters, people believe they are unlikely to be affected
16
Q
Case Study - Cyclone Haiyan
A
- November 2013, Philippines, Vietnam, Taiwan, Cat 5
- US$5.8 billion, 4.1 million homeless, 1.1 million damaged homes, 6400 deaths
- introduced countermeasures to prevent such a disaster from happening again; replanting mangroves, storm surge warning system, Tropical Storm Shelters
17
Q
Case Study - Gorkha Earthquake
A
- 25th April 2015, Nepal, 7.8, 15km depth, collision
- epicentre - Barpak Village, 60km north of Kathmandu
- 8600 deaths, 19000 injured, avalanches, 600,000 homes destroyed, 250,000 homes damaged
- US$10 billion cost
18
Q
Case Study - Mount Merapi
A
- 25th Oct - 30th Nov 2010, VEI 4, destructive, strato, Java Indonesia
- 353 deaths, 577 injured, 350,000 evacuated
- increased education on volcanoes, improved monitoring, more fertile soil, dams built to manage lahars
