The Earth has three major internal components which are the crust, mantle and the core. The core has two distinct parts which are the inner and the outer core. The crust has two types which are the Continental and the Oceanic crust. The earth's internal components has its boundaries/discontinuities which are the Mohorovicic, Lehmann, and Gutenberg discontinuity.

1. THE EARTH’S
INTERNAL
STRUCTURE

2. What is the importance of knowing the
Earth’s Planetary Structure?
Basic knowledge of our planet’s internal structure,
composition, properties and processes is needed to
understand many aspects of our Earth’s natural
surface characteristics.

3. Earth’s Interior:
 Primary composed of solids (densest of the three states of
matter).
 Liquids, lies at the planet surface thousands of kilometers
above the densest solids (not as dense as solids).
 Gases, have the weakest gravitational attractive force and are
held relatively loosely around earth (with even lower density
than liquids).

4. Planet Earth’s
Radius:
6400 km

5. Seismic waves
o These are various shock waves in which
its behavior is used as an important
evidence to gain knowledge about the
earth’s interior.

6. Types of seismic waves:
S waves (secondary) – waves travel more slowly than P waves
and arrives at the seismograph later. They can only move
through solids.
P waves (primary) – waves travel faster and are the first to arrive
at a recording seismogram. They pass through all types of
matter.
Surface wave – is a seismic wave that is trapped and travels
near the surface of the earth.

8. Seismograph -
instrument used
to record the
motion of the
ground during an
earthquake.

9. Seismogram -
the recording of
the ground
shaking at the
specific location
of the
instrument.

10. Difference between Seismogram and Seismograph:
• A seismogram is the paper record of the seismic
waves.
• A seismometer or seismograph is the actual
instrument.

11. Geothermal
gradient -
amount that
the Earth's
temperature
increases with
depth.

12. Earth’s major
components:

14. Core

15. Core
Earth’s innermost section
Contains one third of earth’s mass
Radius – 3360 kilometers (2100 mi)
Composed of iron and nickel

16. Core’s 2 distinct sections:
Inner core
 Radius – 960 km (600 mi)
 Solid
 Density – 13 grams per
cubic centimeter (0.5
lbs/in.³)
 Temperature is about
6900°C (12,400°F)
Outer core
 Radius – 2400 km (1500 mi)
 Liquid (lava)
 Density – 10 grams per
cubic centimeter (0.4 lbs/in
³)
 Temperature is about
4800°C (8600°F)

17. Mantle

18. Mantle
 Largest among the earth’s interior zones
 Contains nearly two thirds of earth’s mass
 Radius – 2885 km (1800 mi)
 Composed of solid rock matter with silicate
rocks (high in silicon and oxygen)
 Solid
 Density – 3.3 to 5.5 grams per cubic centimeter
(0.12 – 0.20 lbs/in.³)

19. There is a boundary between the mantle and the
crust marking the change of density called a
discontinuity, scientists call it Mohorovicic
discontinuity (Moho).

20. Crust

22. Crust
 Earth’s solid exterior
 Described as a earth’s hard outer shell
 Outermost layer of solid earth
 Represents only 1% of earth’s mass
 Composed of a great variety of rock types
 Density – 2.7 to 3.0 grams per cubic
centimeter (0.10 to 0.11 lbs/in.³)

23. Two kinds of Earth’s Crust:
Oceanic Crust
 Crust beneath the oceans
 Radius – 3 to 5 km (2 – 3 mi)
 Composed of basalt, a heavy, dark-colored,
iron-rich rock that is high in silicon(Si) and
magnesium(Mg)
 Liquid
 Density – 3.0 g/cm³

24. Continental Crust
 Comprises the major landmasses on earth
exposed to the atmosphere.
 Almost 3 times thicker than the oceanic
crust
 Contains more light-colored rocks and can
be granitic in composition.
 Radius – 20 to 70 km (12 – 44 mi)
 Solid
 Density – 2.7 g/cm³

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LISTENING!