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Natural disasters - Coggle Diagram
Natural disasters
Earth's layers
Inner core
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Although the temperature of the inner core is high enough to melt the iron and other elements, it remains solid because of the great pressure exerted by the other three layers.
Outer core
The outer core is made up of molten iron, sulfur, and other elements.
Although molten, the outer core is slightly cooler than the inner core.
Mantle
Above the outer core is a much thicker, hot layer called the mantle.
The temperature of the mantle is over 1,000°C, but it is not hot enough to melt the minerals found in the mantle.
The mantle is more like hot plastic, and can be deformed by pressure.
Crust
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The crust is solid and brittle, and “floats” on the mantle as a cluster of tectonic plates.
Avalanches
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Earthquakes and eruptions can trigger avalanches by shaking the surface layers of soil and rock loose.
Heavy rains cause avalanches by increasing the weight of the surface layer and making it more plastic so that it is easier for the surface to start moving.
Heavy snowfall on a steep slope can cause an avalanche if too much snow builds up on too steep a surface.
Earthquakes
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When the tension between the plates grows high enough, they slip past each other or they slip on top of and underneath each other. The slipping is the earthquake.
The greater the pressure built up between the plates, the greater the motion of the plates and the more powerful the earthquake.
Tsunamis
Tsunamis are giant waves caused by earthquakes or volcanic eruptions beneath the ocean. The movement of the Earth beneath the water lifts the water and starts it in motion.
As the moving water approaches land, the water near the shore falls back to become part of the growing wall of water.
Tsunamis are also known as tidal waves because the seaward movement of the water near the shore looks like the tide going out quickly.
Tsunamis can reach heights of 10 to 100 feet and they flow over the land with tremendous power when they strike.
Professions
Seismology is the study of the movement of the Earth. Seismologists study earthquakes, avalanches, mudflows, and tsunamis.
Volcanology is the study of volcanoes, their eruptions, and the materials ejected from a volcano during an eruption, including lahars.
Both sciences fall under the more general science of geology. Geologists are scientists who study the Earth in all of its aspects.
Mudflows
Mudflows are movement of surface materials caused by intense rainfall, sudden overflowing of lakes or bursting of dams.
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Lahars
Lahars are made from volcanic material such as volcanic ash or lava mixed with water. The water source for a lahar is typically from a stream, river, glaciers, or lake water.
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