Hazardous Earth Flashcards
What is the Crust?
The thin layer of solid rock that cases the mantle beneath
Types of crust?
Oceanic and Continental
How thick is oceanic crust?
6-8 km thick
How thick is continental crust?
30-50 km thick
What is oceanic crust made from?
Basalt (Dense Igneous Rock)
What is continental crust made from?
Granite (Low Density Igneous Rock)
What is the lithosphere?
A layer consisting of the crust and upper mantle
What is the asthenosphere?
The top layer of the mantle
What is the physical state of the outer core?
Liquid
What is the physical state of the mantle?
A viscous fluid
What physical state is the inner core?
Solid
Where do convection currents occur?
Outer Core and Mantle
What is a convection current?
The process by which heat is transferred from the core to mantle and mantle to crust. Hotter parts of the mantle/core rise to the top of their layer. Then, they cool and sink back down.
List the different sections of the Earth from the centre outwards.
Inner Core, Outer Core, Lower Mantle, Upper Mantle (Lithosphere, Asthenosphere) and Crust (Lithosphere)
What is the mantle made from?
Peridotite
What is the outer core made from?
Iron and Nickel
What process heats the earth from within?
Radioactive decay of elements like Uranium and Thorium in the core and mantle.
What is a conservative plate boundary?
Two plates sliding past one another.
What does a conservative plate boundary cause?
- Destructive earthquakes, magnitude 8.5
- Small daily tremors
- No volcanoes
What is a divergent plate boundary?
When two plates move apart
What does a divergent boundary cause?
- Small earthquakes, magnitude 5-6
- Not very explosive or dangerous volcanoes
- Occurs in fissures (cracks in crust)
- Erupts basalt lava at 1200 degrees
What is a convergent plate boundary?
When one plate is pulled under the other
What does a convergent plate boundary cause?
- Very destructive earthquakes, magnitude 9.5
- Tsunamis
- Very explosive, destructive, steep, cone-shaped volcanoes
What is a collision zone boundary?
When two plates collide, forcing both upwards
What does a collision zone boundary cause?
- Destructive earthquakes, magnitude 9.0
- Landslides
- Volcanoes are very rare
Name an example of a conservative plate boundary
San Andreas Fault