Internal Structure Of The Earth

Question 1

The earth’s interior is divided in terms of composition, into three major layers:

✔ crust

✔ mantle

✔ Core

Question 2

✔ Outermost layer
✔ Consists mostly of rocks including granite and basalt
✔ Where the different landforms, oceans and seas are formed
✔ Has a definite boundary (Moho-separates the crust from the mantle)

Answer 2

Crust

Question 3

Types of crust

thicker and less dense than oceanic crust; average thickness is about 20-40 km
but under mountain ranges it can be as 70 km thick; made up of mostly granite
which is less dense

Answer 3

Continental Crust

Question 4

Types of crust

denser and thinner; average thickness is about4-7 km; made up of mostly basalt which is denser

Answer 4

Oceanic Crust

Question 5

✔ Largest layer under the crust consisting of about 80% of the Earth’s volume
✔ About 2 885 km thick
✔ Composed of element silicon, oxygen, iron, and magnesium
✔ Peridotite- the main rock type that makes up the mantle
✔ Its temperature ranges from about 871 ºC under the crust and 2 204 ºC near the outer core

Answer 5

Mantle

Question 6

described as the steady increase in temperature with depth

This is responsible for the different behaviors of rocks. Rocks in the upper mantle are cool and brittle while the rocks in the lower mantle are hot and soft but not molten. Rocks in the upper mantle are brittle enough to break under stress and produce earthquakes. Rocks in the lower mantle are soft and when subjected to force, they flow instead of break.

Answer 6

Geothermal gradient

Question 7

✔ Innermost layer of the Earth
✔ Has radius of about 3 460 km
✔ Its temperature is hotter than the mantle reaching up to about 5 500 ºC
✔ Highly dense and is divided into two parts

Answer 7

Core

Question 8

✔ Liquid layer of the Earth that lies underneath the mantle
✔ Consists mainly of liquid metals such as iron and nickel
✔ Approximately 2 254 km thick
✔ Has a temperature ranging from 2 204 ºC to 4 982 ºC

Answer 8

Outer core

Question 9

✔ The center of the Earth
✔ Made up of solid nickel and iron
✔ Has a temperature ranging over 4 980 º C
✔ Under a great amount of pressure(132Mkg/cm²). The extreme pressure compresses the inner core to a solid state despite the fact that it is even hotter in this layer than the liquid outer core.

Answer 9

Inner core

Question 10

How does the internal structure of the earth influence plate tectonics?

Answer 10

As the Earth rotates, the liquid outer core spins, creating the Earth’s magnetic field. Not surprisingly, the Earth’s internal structure influences plate tectonics. The upper part of the mantle is cooler and more rigid than the deep mantle; in many ways, it behaves like the overlying crust.