Volcanoes and Earthquakes Flashcards
Name the structures of the Earth?
Inner Core, Outer Core
Mantle and Crust
What are the characteristics of the Inner Core
Radius of 1220
Solid metal
Made out of iron and nickel
Temperature of 6000 degrees Celsius
What are the characteristics of outer core?
Made out of iron and nickel
2300 km thick
temperature 4400 degrees
grows 1mm per year
What are the characteristics of mantle
2900km thick
84% of the Earths Volume
colour green
Temperature 1000 degrees C - 3700
What are the two types of crust
Oceanic crust and continental crust
What is a plate boundary?
A plate boundary is an area of the Earth’s crust where two plates meet in gerneral. We find earthquakes and volcanoes at these places.
What are the levels of activity in a Volcano?
Extinct - a volcano that hasn’t erutped in the last 10,000 years
Active - A volcano that has erupted in the past 2000 years
Dormant - a volcano that has erupted in the last 10,000 years
What is a composite volcano
Composite volcanoes are found on destructive plate margins, where the oceanic crust sinks beneath the continental crust. Composite volcanoes have the following characteristics:
Acidic lava, which is very viscous (sticky).
Steep sides as the lava doesn’t flow very far before it solidifies.
Alternate layers of ash and lava. For this reason, they’re also known as stratovolcanoes. Strato means layers.
Violent eruptions.
Longer periods between eruptions.
What does shield volcano?
Shield volcanoes are found on constructive plate margins, where two plates move away from one another. Shield volcanoes have the following characteristics:
basic lava, which is non-acidic and very runny
gentle sides as the lava flows for long distances before it solidifies
no layers, as the volcano just consists of lava
less violent eruptions
shorter periods between eruptions
When do earthquakes occur
They occur when two plates stick due to friction. Pressure builds up in the plates until the pressure exceeds the friction. The plates slip past each other causing the earthquake.
Name the two things we measure earthquakes with
Seisometer and Richter Scale
What is the focus?
The point in the crust where the pressure is released is called the focus
What is the waves of energy called when an earthquake happens?
When the pressure is too much it is suddenly released and waves of energy, called seismic waves, occur.
What are the impacts of an earthquake?
Buildings may collapse due to the shaking of the ground.
People may die if they are inside a building when it collapses.
Roads may be blocked, gas and water pipes could be broken and electricity could be cut off.
What are the secondary effects?
The cost of rebuilding may be high.
Trade will decrease, especially if the infrastructure (roads, airports etc) have been damaged.
Spread of diseases may rise. If dead bodies are left in the open for a long period of time they can cause a risk of infectious diseases, such as tuberculosis and hepatitis B.
Poor sanitation may occur if water pipes were broken during the earthquake.
