Natural Disasters Flashcards
What is the lithosphere?
Lithosphere – Rigid outer layer, which consists of crust and the upper part of the mantle. Floats on the asthenosphere – upper part of the mantle.
Form in to out label the MAIN sections of the Earth.
Inner core
Outer core
Mantle
Crust
What is the Moho discontinuity?
Moho discontinuity – the division between the crust and the mantle
What is the sial?
Sial – Land part of the crust
What is the sima?
Sima – Sea floor part of the crust but also runs underneath the continents.
Three types of rocks?
Ingneous
Sedimentary
Metamorphic
Igneous rock?
Igneous: “Fire” – formed by cooled magma (intrusive) or cooled lava (extrusive)
Sedimentary rock?
Sedimentary: “Layered”- formed by the laying down of sediments (small fragments of rock)
Metamorphic rock?
Metamorphic: “to change form” – formed by sedimentary or igneous rock that have been changed by great heat or pressure
Who and when was continental drift discovered?
In 1912 a German meteorologist called Alfred Wegener
When all continents were joined what was the landmass called?
Pangaea
List 4 facts of proof that he was correct.
Shapes of continents fit into one another
Fossils and minerals found on different continents were the same
Coal was found in Antartica
Matching striations on different continents
How do the continents move?
Heat in the mantle causes convection currents which cause the plate to move. Heat from below causes molten rock to expand and then rise to the top of the convection cell where it moves sideways and eventually downwards to complete the cell.
What other thing does the heat from the mantle do?
As heat rises from the mantle it deforms the crust and breaks into large sections called tectonic plates. Most tectonic plates carry both oceans and continents.
What are the edges of the plates called?
The edges of the plates are called plate boundaries.
What is convergent movement?
Plates moving together.
What is transform movement?
Plates moving side by side.
What is divergent movement?
Plates moving apart.
How is a Earthquake formed?
Plate movements cause cracks or faults in the crust. The faults produce great stresses which cause vibrations in the Earth’s crust. These vibrations are called earthquakes.
What is the name used for the scale which measures the intensity of the Earthquake?
Richter Scale
What is an Tsunami?
A tsunami is a series of great sea waves caused by an underwater earthquake, landslide, or volcanic eruption. More rarely, a tsunami can be generated by a giant meteor impact with the ocean.
In an earthquake, what is the point on the surface directly above the focus point? And what can occur here?
It is called the epicentre, and liquification can occur here.
What is the focus if an earthquake?
The exact point where the earthquake occurred.
What is the fault of an earthquake?
The line along which the earthquake occurred.
What is volcanism?
The process where molten magma from the mantle moves to the Earth’s crust.
What is the difference between ‘intrusive volcanism’ and ‘extrusive volcanism’?
Intrusive volcanism happens when the magma forms igneous intrusions into rocks of the Earth’s crust.
Extrusive volcanism happens when the magma erupts at the surface.
List 5 ingneous intrusions.
Dyke Sill Lopolith Pipe Batholith
What is the most common type of volcano?
Composite volcano
What is a tropical cyclone?
A Tropical cyclone is a relatively small, intensely developed low pressure cell that usually occurs over warm oceans.
