Geography Natural Hazards (Tectonic Hazards) Flashcards
Fold mountains form when…
two continental plates converge AT A COLLISION PLATE MARGIN, forcing the crust upwards into mountains
Layers of the earth are… and are made of…
Crust (rock), upper & lower mantle (semi liquid layer of molten magma), outer core (liquid iron and nickel) and inner core (solid iron)
Stratocones are…
Cone shaped volcanoes found at destructive margins with steep sides and made of layers of ash and lava. They are made of viscous acidic lava, and erupt violently but infrequently, eg. Mt Pinatubo
Shield volcanoes are…
Dome shaped volcanoes formed at constructive margins with gentler sloping sides due to being made of runny, basic lava which can flow further. Erupt less violently but more frequently
What is a constructive plate boundary?
Where two tectonic plates move AWAY from each other. Magma rises to fill the gap, new land is created, features like shield volcanoes formed. Eg. Atlantic Ridge
What is a destructive plate boundary?
Where two plates converge and the OCEANIC PLATE goes UNDER the CONTINENTAL PLATE. Landforms such as stratocones can be formed, as well as earthquakes. Eg. Himalayas
What is a conservative plate boundary?
Where two tectonic plates slide past each other, and can be in opposite directions or the same direction but at DIFFERENT SPEEDS. Does not form volcanoes, but can often cause violent earthquakes due to sudden slips, eg. San Andreas Fault, California
What is continental crust?
Quite think (20 - 70 km), but not very dense. Mostly made of granite
What is oceanic crust?
Much denser and thicker than continental crust, however not very thick, (5 - 10 km). It is subducted UNDERNEATH continental crust
What are the 4 main management strategies for reducing risk from tectonic hazards?
- Monitoring
- Prediction
- Protection
- Planning
Ways to monitor volcanoes?
- Remote sensing (through satellites)
- Seismicity
- Ground deformation
- Geophysical measurements (changes to gravity as magma rises)
- Gas detection
- Hydrology (gas dissolved in water)
What is prediction based on?
MONITORING
How can we divert lava flow from property?
Earth Embankments or Explosives, (eg. Mt Etna)
How can buildings be protected from earthquakes?
- Reinforced Walls
- Shock Absorbers
- Automatic Shutters
- Open Areas (for evacuation)
- Rolling weights on roof to counteract shock waves
What are plate margins?
Where tectonic plates meet
Causes and background of Haiti Earthquake 2010
- 2010
- Poorest country in Western hemisphere
- Magnitude 7
- Epicentre just 24km South of Port-au-Prince
- Shallow focus of 13km
- On conservative plate margin between NA plate and Caribbean plate
Social impacts of Haiti 2010
- More than 300,000 buildings collapsed
- 1.3 million made homeless
- Around 300,000 people died
Economic impacts of Haiti 2010
- 30,000 commercial buildings collapsed
- Port and airport damaged
- $7.8 - $8.5 billion in damage
Environmental impacts of Haiti 2010
- Small landslides
- Oil spills
Short term responses to Haiti 2010
- Dominican Republic supplied water, medical supplies and machinery
- Rescue teams, such as Red cross arrived from many countries
- USA provided rescue teams and 10,000 troops
Long-term responses to Haiti 2010
- Governments and organisations donated $13.5 billion
- Appeals in other countries were launched
- Ports, new homes and schools were rebuilt
- Small farmers were supported
Why was Haiti affected so badly?
Lack of regulation due to poverty
2/3 of population were unemployed before the quake, so recovery was poor
Government had little money so facilities such as emergency services were poor
1/2 of Haiti’s population was poor so facilities were poor
How does being in poverty affect risks to natural disasters?
Limited resources, lack of education and health services can increase exposure to risks
Primary Effects of Eyjafjallajökull
Eruption turned day to nigh because of the ash clouds
Plane flights were cancelled
Homes and roads were destroyed
Secondary effects of Eyjafjallajökull
Sporting events were cancelled due to cancelled flights, which impacted tourism industries
Fresh food imports were halted
Local water supplies were contaminated by fluoride
Flooding was caused by glaciers melting
Europe lost over 6 million per day from loss in tourism
Worldwide, businesses lost billions
Immediate responses to Eyjafjallajökull
State of emergency was declared
EU airspace was closed as a safety precaution
Evacuation of the people happened before the volcano erupted
Long term responses to Eyjafjallajökull
Properties were to be rebuilt
Restoration of utilities
Developing opportunities for economy to recover
What are some relief efforts for future earthquakes in Haiti?
Micro-credit schemes, where charity donates money to civilians to begin a working life
Improvements to buildings where more civilians can live in stable and safe housing
Crop trials were Oxfam invests in making the farmer’s product better to increase efficiency
