Earth Forces Flashcards
How old is our universe?
13.8 billion years old.
How old is our galaxy?
13.6 billion years old.
What is the name of our galaxy?
The Milky Way.
How old is our Solar System?
4.6 billion years old.
What is the Sun called?
Sol - meaning ‘Solar’.
Name the 8 planets in our Solar System? (not Pluto!)
Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
How old is our Planet?
4.5 billion years old.
Where is the Asteroid Belt located?
Between Mars and Jupiter.
What are the 4 main layers of the Earth?
The crust - a thin layer of solid rock
The mantle - a layer of very hot molten rock
The outer core - a layer of very hot molten rock
The inner core - a ball of solid iron
What is the temperature of the inner core?
5000°C - 6000°C.
What state of matter is the inner core in?
Solid.
What is the temperature of the outer core?
4000°C - 6000°C.
What state of matter is the outer core in?
Liquid (molten)
What is the temperature of the mantle?
1400°C - 3000°C.
What state of matter is the mantle in?
Liquid.
What is temperature of the crust.
Around 22°C.
What state of matter is the crust in?
Solid.
What main layer of the Earth is the hottest?
The inner core.
What is the largest layer of the Earth?
The mantle
Can the crust support life?
Yes.
How do we know that Pangaea is real?
- Fossils of dinosaurs that couldn’t swim across oceans found in different continents.
- Rocks found in exactly the same layout found in different continents.
- The shape of the continents make it look like a jigsaw puzzle. ex. South America and Africa fit together.
State 6 tectonic plates.
Juan de Fuca Plate
Pacific Plate
Cocos Plate
North American Plate
Caribbean Plate
Nazca Plate
South American Plate
Scotia Plate
African Plate
Eurasian Plate
Arabian Plate
Indo-Australian Plate
Philippines
Antarctic Plate
Okhotsk.
NAME ANY SIX.
What drives the tectonic plates to move across the planet?
Convection currents.
Where are the plate boundaries?
At the point where tectonic plates meet or move away from eachother.
What is the constructive plate boundary?
This is where the two plates move apart. As the two move apart the earth’s crust is stretched and weakened and cracks begin to appear. Magma is forced up the cracks from convection currents.
Where do most earthquakes and volcanoes occur?
The Ring of Fire.
What is a volcano?
A volcano is an opening or vent in the Earth’s crust through which molten material erupts and solidifies as lava.
What are the three types of volcano?
Active - erupts regularly from year-to-year
Dormant - a volcano that isn’t erupting now but considered likely to erupt in the future.
Extinct - A volcano that has not erupted in millions of years and will never erupt again.
Why are dormant volcano eruptions the most dangerous?
- A lot of pressure has built up over a very long period of time which causes a very dangerous and deadly eruption.
- They are very hard to predict in terms of timing and strength.
- Many people live near them as they haven’t erupted in a long time
Name 3 things that happen when a dormant volcano erupts
(name any three)
- A huge explosion.
- Poisonous gases and ash are released into the atmosphere.
- Lava bombs fly from the crater.
- Lava flows down the mountainside
- The pyroclastic flow which destroys almost everything in its path as it is superheated rock and ash travelling at several hundred miles per hour.
What are the two scales used to measure earthquakes?
The Richter Scale and The Mercalli Scale.
What do seismologists use to measure earthquakes?
They use a scientific instrument known as a seismometer.
What does the Richter Scale measure?
The Richter Scale measures the magnitude of an earthquake. It is also a logarithmic scale - meaning that a magnitude 2 earthquake is 10x stronger than a 1 and a magnitude 3 earthquake is 10x times stronger than a 2. This means that a magnitude 3 earthquake is 100x stronger than a 1.
What does the Mercalli Scale measure?
The Mercalli Scale measures the damage an earthquake causes based on observations.
What are the primary effects of an earthquake? Name four things.
- Injury.
- Destruction of buildings.
- Death.
- Tsunamis and volcano eruptions.
- Landslides
- Services destroyed
- Roads and railways destroyed.
What are the secondary effects of an earthquake? Name four things,
- Economic suffering
- Real estate price drops
- PTSD of the residents
- People will leave for other places
- Millions homeless
- Disease widespread
- Businesses destroyed
- Food and water shortages
What is the focus of an earthquake?
It is where the two plates jerk apart and where the seismic waves come from
What is the epicentre of an earthquake?
It is the point directly above the focus. It is where the most damage occurs
What do developed countries (ex. Japan) have for earthquake proofing that developing countries (ex. India) don’t have?
- They have more money
- Takes less time to complete a structure
- Expensive materials
- Stronger materials
What are the disadvantages that a DEVELOPING country faces when trying to build an earthquake proof building (ex. India)?
- Less money
- Takes more time to complete buildings
- Cheaper materials
- Weaker materials
How many stars are in the Milky Way?
100 billion.
How many galaxies are in our universe?
100 billion.
What two tectonic plates are volcanoes usually found at?
Where two tectonic plates COLLIDE (destructive) or MOVE APART (constructive).
Which plate boundaries have the most deadly earthquakes?
At tectonic plates which are COLLIDING (destructive) or SLIDING PAST EACH OTHER (conservative).
How do rich countries such as Japan prepare for earthquakes?
- They spend millions trying to predict earthquakes but this is very difficult.
- They build earthquake proof buildings
- They have emergency supplies of food, water, shelter and medical equipment.
- They have highly skilled rescue teams available.
Developing countries such as Pakistan, they are not as well prepared for earthquakes because…
- Their buildings are weak and poorly built
- They have no money to train rescue teams or provide equipment.
- They have no money to rebuild housing, transport and services.
- They have a shortage of medical supplies, emergency food and water.
Describe the magma chamber in a volcano.
A huge reservoir of lava under the volcano.
Describe the function of the main vent in a volcano.
The main tube which the lava shoots out from (there may also be smaller secondary vents).
Describe the crater in a volcano.
The hole at the top of the volcano.
What is the theory of continental drift?
Millions of years ago all the continents were joined together to make one super continent called Pangaea. They have slowly floated apart into their present positions and continue to move today. This is the Theory of Continental Drift.
What is the destructive (colliding) plate boundary?
This is where the two plate collide and create fold mountains.
What does the conservative plate do?
These two plates slide past each other, creating friction. They can be stuck for hundreds of years causing them to jerk apart under pressure. This makes the ground shake violently.
How did the layers of ash and hardened lava come to be?
From previous eruptions
What are seismic waves in an earthquake?
The shock waves that are sent out from an earthquake.
What is the destructive (subduction) plate?
It is when 2 plates collide with the continental plate staying on top, and the oceanic plate subducts, creating magma and pressure.
