Restless Earth Flashcards
Name the layers of the earth starting from the middle?
Inner Core Outer Core Mantle Crust Asthenosphere
What is the core made out of?
Iron/Nickle
There are two types of crust what are they?
Oceanic Crust and Continental Crust
What are these crusts made out of?
Oceanic Crust - Basalt
Continental - Granite
Information on the thickness of the crusts?
- Continental crust is the THICKEST between 25-80km thick
- Oceanic crust is the THINNEST with millions of tonnes of seawater on top of it but this also makes it the densest plate it is between 6-8km thick
Name 4 tectonic plates?
- Eurasian plate
- North American plate
- South American plate
- Pacific plate
- Antarctic plate
- African plate
- Australian plate
- Nasca plate
What are CONVECTION CURRENTS?
Nuclear decay in the core causes heat which heats up magma. This magma rises towards the crust, while this is happening cool magma at the crust falls towards the core this causes CONVECTION CURRENTS
How do the Tectonic plates move?
The convection currents move along the crust pushing it
What are the 4 types of plate boundary?
- Collision zones
- Conservative plate boundary
- Constructive plate boundary
- Destructive plate boundry
Collision Zones
- Himalayas formed as the eurasian and indian plates PUSH into each other
- Destructive earthquakes magnitude 9.0
- Volcanoes are very rare
Conservative plate boundaries
- San andreas fault as the north american and pacific plates SLIDE past each other
- Small earthquakes every day
- Destructive earthquakes up to magnitude 8.5
- No volcanos
Constructive plate boundaries
- Iceland on the mid atlantic ridge there plates PULL apart from each other
- Eurasian and North American plates pulling apart
- Small earthquakes 5.0-6.0 magnitude
- volcanos erupt basalt lava at 1200 C
Destructive plate boundaries
- Oceanic plate ALWAYS SUBDUCTS under
- Andres mountains
- Very destructive earthquakes 9.5 can cause earthquakes
- Very explosive volcanoes steep sided erupt andesite lava 900-1000 C
Stratovolcanoes are..
- formed at destructive plate boundaries
- these volcanoes are composed of alternating layers of lava and ash other volcanoes are just lava
- andesite lava (acidic) flows a short distance and produces steep sides
Shield volcanoes
idgaf
Advantages of a volcano
- geothermal energy
- tourism
- fertile soils (grow crops to make money)
Disadvantages of a volcano
- acidic water can cause pollution and crops to fail
- eruptions (wipe out everything in its radius)
- ash ( grounds planes and communication)
Where would you find volcanoes and why
- volcanoes are MOSTLY near destructive plate boundaries
- the andesite magma is less dense than the magma in the mantle so it rises and pushes through the continental plate and forms a volcano
- they also form at constructive plate boundaries
What is Pyroclastic flow
- the most dangerous
ash and rock fall like an avalanche at 500 C and 80mph
What is Lava flow
- rarely any deaths
you can walk away from it
What are Volcanic bombs
- damages buildings and towns people are killed
massive rocks being thrown up into the air
What is Lahar
when ash and snow mix it creates thick muddy water that carries boulders
How to prepare for a volcanic eruption (EDUCATION)
- people can be given advice on what to do
- schools can teach kids about eruptions
- volcanic drills
How to handle a volcanic eruption (EMERGENCY ACTION)
- frequent advice and news updates
- planes grounded
- danger zones can be sealed off ( restricted areas)
How to prepare for a volcanic eruption (FORWARD PLANNING)
- people in danger zones can stock up in necessities
- concrete lahar channels can be built
- people can take out insurance
- concrete shelters
An LEDC volcanic erupton
Montserrat, Mount Soufriere 1997
