Download PowerPoint Presentation - The Interior of the Earth

The Interior of the Earth
I. Studying the Earth’s Interior
A. Scientists study the structure of the earth’s
interior using seismic waves.
B. There are different types of seismic waves:
1. Surface waves roll along the surface of the
earth as swells
2. Waves that penetrate the interior of the earth:
 Primary (P-waves)
move quickly, can penetrate both liquids and
solids
 Secondary (S-waves)
can penetrate solids, not liquids
C. P-waves and S-waves are
used to determine the
composition and structure
of the earth’s interior.
Changes in wave
direction and speed
indicate changes in
composition and
physical properties
(temperature, state of
matter)
II. Characteristics of Earth’s Interior
A. Activity inferred from seismic studies:
Liquid and plastic layers are convective:
 due to heat escaping from the core through the mantle.
 material moves from high heat (low density)to low heat
(high density).
 as this occurs in the mantle it causes lithosphere to glide.
II. Characteristics of Earth’s Interior
B. Physical Properties inferred from seismic studies.
1.
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Inner Core:
state of matter - solid
composition - iron
depth - 5150-6370 km (3219-3981 miles)
temperature - 6300-6500 °C
pressure - 3.2-3.8 million atm
density - 12.7-13.0 g/cm3
% of Earth’s mass - 1.7%
II. Structure of Earth’s Interior
2. Outer Core:
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state of matter - molten (liquid)
composition - iron, small amounts of nicke
depth - 2890-5150 km (1806-3219 miles)
temperature - 5000-6300 °C
pressure - 1.5-3.2 million atm
density - 9.9-12.7 g/cm3
% of Earth’s mass - 30.8%
3. Lower Mantle:
 state of matter - stiff plastic (solid)
 composition - silicon, magnesium, oxygen, iron,
aluminum
 depth - 650-2890 km (406-1806 miles)
 temperature - 2500-5000 °C
 pressure - 0.4-1.5 million atm
 density - 3.3-9.9 g/cm3
 % of Earth’s mass - 49.2%
4. Upper Mantle (includes transition zone & asthenosphere):
 state of matter - soft plastic (liquid)
 composition - silicon, magnesium, oxygen, iron,
aluminum
 depth - 50-650 km (6-406 miles)
 temperature - 5000-2500 °C
 pressure - 0.1-0.4 million atm
 density - 3.3-3.0 g/cm3
 % of Earth’s mass - 17.8%
5. Lithosphere and Crust (includes tectonic plates):
 state of matter - brittle (solid)
 composition - silicon, magnesium, oxygen, iron,
aluminum, sodium, potassium
 depth - 0-50 km (0-31miles)
 temperature - 0-500 °C
 pressure - 1 – 100,000 atm
The remaining 0.1%
of the earth’s mass is
 density - 0-3.0 g/cm3
living material.
 % of Earth’s mass - 0 .4%
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