Diagram of the structure of the earth:
Geography.parkfieldprimary.com. (2018). The Structure of the Earth - Primary School Geography Encyclopedia. [online] Available at: http://geography.parkfieldprimary.com/rocks-and-soils/the-earth [Accessed 12 Oct. 2018].
The inner core is made of molten iron it is the hottest part of the earth, the crust is a solid layer that is rocky it’s made out of 3 types of rock (igneous, metamorphic, and sedimentary rocks.)
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Below the crust is the mantle it’s made of rock that is denser than rocks common in the crust.
- Atmosphere: The gases which surround the earth these gases can be toxic like carbon dioxide.
- Biosphere: the part of the world where people are other organisms live.
- Lithosphere: the outer part of the earth that is made up of the crust and the upper mantle.
- Hydrosphere: the water on the surface of the earth like oceans and lakes this can even include clouds.
The rock cycle:
Opentextbc.ca. (2018). 3.1 The Rock Cycle – Physical Geology. [online] Available at: https://opentextbc.ca/geology/chapter/3-1-the-rock-cycle/ [Accessed 12 Oct. 2018].
The three main rock formed are igneous, sedimentary and metamorphic. Sedimentary rocks are formed from sediment compacted until they are solid. Metamorphic rock are formed when rocks are changed by heat and are pushed down from pressure this may be due to a heavy material. Instructive igneous rocks are slowly cooled magma below the Earth’s surface forming large crystals. Extrusive igneous rock is magma that is quickly cooled on the surface forming small crystals.
Plate tectonics: There are two types of plates the oceanic which is plates that have an ocean on top of them and are much thinner than the continental plate and the continental plate which has land on them is the thicker plate.
There are 3 types of plate boundaries that are involved with plate tectonics (constructive, conservative and destructive.)
- Constructive is where two plates diverge apart this could be either oceanic plates or continental.
- Conservative is where two plates move past each other in different directions.
- Destructive is where an oceanic plate and a continental plate meet. This normal means they will collide causing tension, then the plates jolt quickly consequently causing an earthquake and volcanoes.
The changed in the Earth: it is believed that the Earth’s surface is much cooler now than in the past because the number of volcanic eruptions has decreased. Also some of the continents (South America, Africa, India, Antarctica and Australia) where connected to make a super continent. This is believed to be true due to a geophysicist and meteorologist named Alfred Wenger. He discovered that look-alike animal and plant fossils and similar rock formations are found on different continents. Also the continents fit together like a puzzle.
Society, N. (2018). continental drift. [online] National Geographic Society. Available at: https://www.nationalgeographic.org/encyclopedia/continental-drift/ [Accessed 12 Oct. 2018].
Earthquakes and Volcanoes:
A volcano is a mound that has a vent or a crater which lava and hot vapour has been erupted from the crust. There are four types of volcanoes.
Composite volcanoes are very explosive they are made up of ash and lava that has erupted and cooled and hardened to form layers.
Internet Geography. (2018). Shield and Composite Volcano Quiz - Internet Geography. [online] Available at: https://www.internetgeography.net/shield-and-composite-volcano-quiz/ [Accessed 12 Oct. 2018].
Shield volcanoes are made up of only lava, the lava is runny meaning it flows quickly and spread over a large area.
Anon, (2018). [online] Available at: https://www.bbc.co.uk/science/earth/surface_and_interior/shield_volcano [Accessed 12 Oct. 2018].
Dome volcanoes are made up of only lava, the lava is thick meaning if flows slowly and forms a steep sided volcano.
Pinterest. (2018). This diagram is the lava dome being formed. Lava oozes out of the volcanic central vent where the lava piles up becoming a la… | (1-1) Inside a Volcano | Pinterest | Volcano. [online] Available at: https://www.pinterest.co.uk/pin/291397038360025843/ [Accessed 12 Oct. 2018].
Super volcanos are much bigger than average volcanoes and cover a very large surface (thousands of km) but it is very rare for them to erupt.
Earthquakes are caused occur at the plate margins, they are caused by tension between plates they will jerk past each other and send out a shockwave making the surface shake. They are measured on 2 different scales, the Richter scale and the mercalli scale.
Mountain formations: mountains are formed when the plates smash together causing the rocks and ground to go up.
Fold Mountains are formed when two plates move together this can be two continental or an oceanic plate and it forced rocks upward forming a mound.
Monitoring changes: scientists monitor the changes in the earth and the lithosphere so people are aware what is happening, this can help evacuate people in case there is a change causing chemical leaks, extreme weather and it also effect food chains due to animals being killed. Monitoring also help people gain knowledge, prepare for the changes that may happen and to educate future scientists.
Theories:
The geological fit: Eastern America and West Africa was mapped and it revealed they fit together meaning they were once joined; this supports plate tectonics. The picture shows that the continents fit together but there are places that overlap and there are some gapes but this could be due to weathering and landslides.
Geolsoc.org.uk. (2018). The Geological Society. [online] Available at: https://www.geolsoc.org.uk/Plate-Tectonics/Chap1-Pioneers-of-Plate-Tectonics/Alfred-Wegener/Jigsaw-Fit [Accessed 12 Oct. 2018].
Tectonic fit: fold mountains pieces found in two areas that match when reassembled they creates continues mountain range. Fold Mountains are made when two plates collide forcing rocks upwards.
The British Geographer. (2018). Plate Tectonic Theory. [online] Available at: http://thebritishgeographer.weebly.com/plate-tectonic-theory.html [Accessed 12 Oct. 2018].
Glacial fit: people have found scratches on the bedrock made by blocks of rocks embedded in the ice as the glacier moves these show the direction of the glacier. This how the pates move by the scrapes on the bedrock from the rocks in the ice glaciers but it also shows the direction that certain plate is moving.
Raregoldnuggets.com. (2018). [online] Available at: http://raregoldnuggets.com/wp-content/uploads/glacialgolddeposits.jpg [Accessed 12 Oct. 2018].
Fossil evidence: there have been found many examples of fossil in separate continents suggesting they were joined. This supports plate tectonics due to the same fossils found in different location showing they must have been connected of near for the animals travel to a different area proving the plates move.
Earth How. (2018). PANGEA FOSSILS: Evidence of the Pangea Supercontinent - Earth How. [online] Available at: https://earthhow.com/pangea-fossils-evidence/ [Accessed 12 Oct. 2018].
Jigsaw fit: this is the idea of the coast lines of Eastern America and West Africa fit together 100m below sea level. This supports plate tectonics because it shows they have been connected at some point and they have slowly drifted apart supporting the theory of plate tectonics.
Classroomatsea.net. (2018). Classroom@Sea » Learn » Plate tectonics. [online] Available at: http://www.classroomatsea.net/general_science/plate_tectonics/cont_drift.html [Accessed 12 Oct. 2018].
How scientists minimise the impact of changes to the Earth:
Scientists can measure the different changes if there is an irregular pattern or a point that is out of shape they may consider it as a sign to show they will be a volcano, Earthquake or a tsunami. This could mean saving thousands of lives, this will enable the government to evacuate the towns and cities in danger.
They measure each one differently, they use a Richter scale to measure earthquakes this is how much force the earthquake can release. They can also predict if a major Earthquake is going to occur based on movements of the plates.
Scientists can see sudden movement of the plates which causes tsunamis. The movements of the plates causes massive water displacements and when they water is then pushed out if causes massive waves to form, they may be more than one. They cannot predict how big the wave is going to be before it happens.
They also can minimise the effects of a volcano become some signs show months or weeks before they erupt. They can see if magma moves to the area underneath the volcano meaning it’s going to erupt.
How do the Government minimise the impact of changes in the Earth: The government can offer support after the event has happened they can rebuild houses making people able to sleep and they can also provide food and water, they setup rescue teams to search for trapped civilians.
When a tsunami strikes the government can plan an evacuation route from your home, school, workplace or any other major places people are. They can also use a radio to keep informed of local watches and warnings.
When an earthquake is predicted they can offer training for people who will be effected they may also modify buildings to withstand earthquakes they recommend if your outside when it happens you stand in the part that is open (no trees or buildings nearby.) stay there until it has stopped.
When a volcano is going to erupt they recommend people listen to the authorities so they can help you safely get away from the danger like lava and hot gases. After the eruption has stopped they may also offer support for the people in need, this may be food shelter or even finding family who got lost in the panic. They will also rebuild houses so the people who are now homeless have somewhere to live again.
How do the General public prepare for a volcanic eruption:
When there is a tsunami the public can get to high ground so they are not swept away by the huge waves. They can also stay away from the beaches, people want to watch the wave but if you can see it then you are too close and you may be injured or even be killed. After the general public could offer to help rescue teams find people, they can also help clean up the damages been dealt.
The General public can prepare themselves for the aftershocks during an Earthquake they should also take cover and stay inside. It is more dangerous to be outside but it is recommended if you are to go to an open area where they are no things that can fall and injure you. After the Earthquake the ones who are trapped or injured can help find people in need and offer support like get help if they are trapped.
When a volcano is erupting the citizens should stay as calm as possible and comply with instructions given by authorities. They may set up assembly points to meet at the worst thing to do is panic because they can cause people to injured by people pushing. After the volcano has erupted they will try to help rebuild, a lot of people will lose they valuables because the lava destroys everything including houses, shops and cars. People will need help starting up their lives again.
Different theories about changes in the earth:
There are many theories and ideas. Some get support if they have sufficient evidence like plate tectonic this theory was made of multiple ideas, Arthur Holmes made up the idea of thermal convection to explain the movement of the plates. He said the substances that are heated the density decreases and it then rises until it cools making the density increase making it sink causing it to push the plates apart.
Another idea made by Harry Hess what that the sea floor is spreading, he discovered the oceans were shallower in the middle and it was deepest at the continental plate margins in the Pacific Ocean. Meaning that as the plates moved away it would get deeper at the margins so his discovery supported movement of the plates he also discovered that some flat topped mountains and sunken islands made up the whole shape of the pacific ocean floor.
Frederick Vine and Drummond Mathews idea was that the Earth’s magnetic field changes over time. This suggests the floor of the ocean was made at the oceanic middle ridges then was cut in half. Then later the activity pushed sideways causing the plates to move. This could be true seen as there are waves this may cause the plates to separate.
John Tuzo-Wilson discovered the plate hotspots and the way volcanoes are formed, he used Hawaiian island as an example of a hot spot as these are volcanic islands. He found that volcanos are mostly found at the plate boundaries.
Some other theory’s that support plate tectonics are The Geological fit, Tectonic fit, Glacial deposits, fossil evidence and the jigsaw fit. (described above) these link together these theories provided evidence for Alfred Wengers big idea about plate tectonics people were sceptical because he couldn’t provide evidence and explain how the plates moved. These mini theories helped him explain how continental drift worked.
I believe some theories link together more than others. For example, the tectonic fit and glacial deposits, this is because fold mountains are made by two plates colliding so this means there could be some rock that was swapped (traded places) and also the glacial deposits show the way a pates moving due to the scratches on the bedrock. I also believe the theory that provided the most evidence is the fossil evidence, the geological fit and the jigsaw fit. Because, these link together really well they support each other as the geological fit states the outlines of West Africa and South America fit together meaning they were connected this is backup by the jigsaw fit as this says the coast lines below sea level also matches. These both support the idea of the fossils, if they were connected it means animals could move across the borders. This then means they could die on either side hence why there are fossils found in South America that are the same as West Africa.
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