2.1 Earthquakes and Volcanoes Flashcards
Define epicentre
The point on the Earth’s crust that is directly above the centre of the earthquake.
Define focus
Where the pressure is released underground and where the energy radiates out from.
Describe the features of a stratovolcano
- Found at destructive tectonic plate boundaries
- Extremely violent
- Thick lava
- Steep sides
Describe the features of a shield volcano
- Gently sloping sides
- Less violent (slow lava flow)
- Found at constructive tectonic plates or hotspots
- Thin lava
- No ash produced
- Made of layers of lava
List the effects of an earthquake
Death Loss of home Fire Water pipes burst Water contamination Spread of diseases Tsunami might follow Reconstruction costs Buildings damaged Hard accessibility to essentials
Why do people live in areas where earthquakes can occur?
- Occupationally immobile
- Geographically immobile –> cannot afford to move
- Unaware of the consequences
- Family ties
- Believes it isn’t going to occur
List the effects of a volcanic eruption
Deaths Land destruction: homes, transport, jobs Fire Unemployment Rebuilding costs Poor sanitation Gas suffocation from eruptions Pyroclastic flow Loss of habitats Hard accessibility
Describe the hazards of a volcanic eruption
- Famine + disease (Destruction of housing, not clean water supply, lack of food etc.)
- Lava flows (Destruction of buildings, roads, transport)
- Pyroclastic flow: Hot, solid material which travels down rapidly on slopes –> Cannot escape in time
- Ash falls –> Damages property by burying buildings + hazards to aircrafts
- Acid rain (Sulfur dioxide + hydrogen sulfate → damages buildings, animals, plants by rainfall)
- Tsunami –> Collapse of volcanoes into the sea
List the opportunities near volcanoes
- Tourist site –> job opportunities
- Fertile soil –> lava and ashes form rich, thick soil layer
- Minerals and mining –> Sulfur around the active volcano → benefits economy for trade
- Creates landmass –> Produces new islands, enlarging existing landmass
- Geothermal power from underneath rocks
How can you prepare for an earthquake?
- Build earthquake-proof buildings + roads
- Practice drills
- Educate children about evacuation
- Train emergency services
- Set up warning systems/signs
- Create an evacuation plan
- Emergency food and water supply
- monitoring systems/example, e.g. lasers,
- tsunami warnings,
- warnings sent to cell phones,
- evacuation,
- hazard mapping/areas not built on,
- strong foundations, (allow deeper)
- strengthening, e.g. diagonal bracing,
- ground isolation systems,
- build low rise, building design (if examples not given)
How can you prepare for a volcanic eruption?
- Setup warning system
- Create an evacuation plan
- Train emergency services
- Educate students about evacuation
- Post-eruption plans
- Emergency food and water supply
Describe the features of collision plate boundaries
Where continental meets continental
Plates being forced together at great pressure
Rocks crumble together and form massive mountain chains
No volcanoes
Violent earthquakes
Fold mountains
Example: Himalayas
Describe the features of destructive plate boundaries
- where oceanic meets continental
- oceanic is denser
- oceanic is subducted
- friction
- violent earthquakes
- violent volcanoes
- fold mountains
Describe the features of constructive plate boundaries
- Where any 2 types of plate boundaries move apart from each other (go the other way)
- There can never be any gaps on Earth
- When tectonic plates pull apart magma, the mantle rises up and solidifies to fill the empty space
- Gentle volcanoes
- Gentle earthquakes
- No fold mountains
Describe the features of conservative plate boundaries
- When plates move alongside each other in opposite directions or in the same direction but at different speeds
- Earthquakes
- No volcanoes
- Made up of rock that is brittle and jagged so it is difficult for the plates to slide past each other
- Plates may get stuck sometimes → pressure builds up → jerk forwards
- Sudden movement and release of pressure causes earthquakes
- Example: San Andreas Fault
