Tectonics Flashcards
why do people continue to live in areas with tectonic hazards
- Volcanic soils are fertile which is good for agriculture
- touristic area so generates jobs
- safe for long periods in between eruptions or earthquake events
- Poor people have no choice: money, food and family are seen as more important
monitoring
seismometers can be used for early warning systems
signs of a volcano : tiny earthquakes, escaping gas, changing shape of volcano
prediction
not reliable but can predict movement of tectonic plates
this allows people to evacuate in time and move valuables
protecion
buildings that absorb eathquake’s energy built
existing buildings strengthened with steel frames so less likely to collapse
trenches and barries built to divert lava but nit always sucessful
planning
future development
emergency servises can prepare and practice drills
education so people know what to do
governments can plan escape routes
emergency supplies liek blankets can be stored
constructive plate boundary
-two plates move away from each other
- as the do, a gap is created in the crust
- magma rises from the mantle and fills up the gap creating new land
shield volcanoes and small earthquakes
destructive plate boundary
- two tectonic plates move towards each other
- the heavier denser oceanic plate is forced beneath the continental plate
- this melts and turns into magma which then rises and forced up into the crust creating friction
large earthquakes, composite volcanoes
conservative
two plates move along- side each other
- as they do, pressure builds up as they struggle to move past each other due to friction
large earthquakes, no volcanoes
collision plate boundary
- two plates move towards each other
- crust is pushed from either side as they weigh the same
- forcing the crust to move up creating fold mountains
- as they struggle, earthquakes crates
convection current
magma is heated by the earth’s core, causing it to rise as its less dense
near the surface it cools and sinks back down
this causes pates to move
earth structure
inner core, outer core, mantle, crust
epicentre
the point on the earth’s surface vertically above the focus of teh earthquake
focus
the point where pressure is released
Disadvantages of living in areas at risk from seismic hazards.
In seismic areas ground shaking causes bridges and buildings to collapse,
windows to shatter, power lines to collapse, water/gas mains and sewers to
fracture.
* Immediate deaths and injuries result from crushing, falling glass, fire and
transport accidents.
* People become homeless.
* Slope failures set off avalanches.
* There may be panic, fear and hunger.
* Longer term disadvantages include diseases spread from polluted water,
civil disorder, looting, power cuts, reduced emergency services,
unemployment, disability, loss of farmland and food production.
Disadvantages of living in areas at risk from volcanic hazards
Volcanic eruptions can kill people and damage
* Economic activity can suffer as it is hard for businesses to operate after an
eruption.
* Habitats and landscapes are damaged by lava flows.
* Ash disperses in the air, and together with volcanic gases can affect
breathing. It may cover the land, including fields, houses, roads, and
industrial plants.
* Pyroclastic flows can destroy houses and trees.
Eruptions may trigger tsunamis, which lead to destructive flooding of the
coastline.
