The document summarizes information about the internal layers of Earth. It describes Earth's core, mantle, and crust, along with their compositions, depths, densities, seismic velocities, temperatures, and other properties. The core is divided into a solid inner core and liquid outer core. The mantle is divided into upper and lower sections. The crust varies in thickness and composition depending on if it is continental or oceanic crust.

1. About Earth and Internal
Layers
SHIVAM VISHWAKARMA

2. About Earth (Fact Sheet)
 Shape: Oblate Spheroid
 Diameter(average): 12734 km
 Radius:
 Equatorial Radius: 6378 km
 Polar Radius: 6357 km
 Average Radius: 6367 km
 Difference in Radii: 22 km
 Gravity:
 g-value at the surface of the earth: 9.8 m/s^2
 g-value decreases with depth and altitude.
 g-value is minimum at the equator and maximum at the poles.
 g-value is zero at the center of the earth.

3. About Earth (Fact Sheet)
 Mass of Earth: 5.97 × 1024
kg
 Density: 5.5 g/cc
 Escape Velocity: 11.2 km/s
 Rotation Period: 23 hr. 56 min. 4 sec (23.9 hr).
 Length of day: 24 hrs.
 Distance from the sun:
 Perihelion Distance: 147.1 × 106
km
 Aphelion Distance: 151.1 × 106
km
 Average Distance (1 Astronomical Unit AU): 149.1 × 106
km
 Orbital Period: 365 days or 1 Year
 Eccentricity: 0.017
 Angular Velocity of Earth: 7.28 × 10−5
radian/sec
 Tangential Velocity of Earth: at equator 1671.48 km/hr, at pole 0.0 km/hr

4. About Earth (Fact Sheet)
 Orbital Velocity
 At Perigee point: 29.9 km/s
 At Apogee point: 29.5 km/s
 Average orbital velocity: 29.7 km/s
 Orbital Inclination: 0.0°
 Obliquity Angle: 23.4°
 Mean Temperature: 15°C
 Surface Pressure: 1 atm
 Number of Satellite: 1
 Interior layers: 3 (Crust, Mantle, and Core)

5. Formulae
 Mass of the celestial body: M =
g×R2
G
, where g is the acceleration due to gravity, R is the radius of
the celestial body, G is the universal gravitational constant: G = 6.67 ×
10−11m3
kgs2
 Escape Velocity: 𝐕𝐞𝐬𝐜 =
2GM
R
km/s
 Eccentricity of the orbit: e =
Ra−Rp
Ra+Rp
, where Ra is the aphelion distance and Rp is the perihelion
distance. If e1: elliptical orbit, e0: circular orbit.
 Kepler’s Planetary laws:
 1st law: Law of orbit.
 2nd law: law of the area or conservation of angular momentum.
∆A
∆t
=
L
2M
, where ∆A is swept area, ∆t is the
time interval, L is the angular momentum, and M is the mass of the planet.
 3rd law: law of time period. T2
∝ a3
,where T is the time period, a is the semi-major axis (aphelion distance).
T2
=
4π
GM
a3

6. Formulae
 Kepler’s 3rd law for two planets:
T1
2
T2
2 =
a1
3
a2
3
 Newton’s law of Gravitation: F =
m1m2
r2 , where m is the masses of the celestial body, r is the
distance between two celestial bodies.
 g-value for the planet: g = G
M
R2, where M is the mass of the celestial body, R is the radius of
the celestial body.
 g-value with altitude: gh =
GM
(R+h)2, where h is the altitude from the surface of the celestial body.
 g-value with depth: gh = g(1 −
d
R
), where d is the depth.

7. Formulae
 Orbital velocity of the celestial body around the star: v2 =
GMs
(Rc+h)
, where Ms is the mass of the star,
Rc is the radius of the celestial body, and h is the distance between the star and the celestial
body, which either may be perihelion or aphelion distances.
 Angular Velocity: ω =
θ
T
=
s
rT
=
V
r
=
2π
T
,where θ is the position angle, s is the length of the arc, r is
the radius of the circle, V is the linear velocity, T is the time.
 Tangential velocity: v = rω, where ω is the angular velocity.
 In the case of equator: vequator = requator × ωcelestial body
 Tangential velocity with latitude: v = rωCosL, where L is the latitude.
 Tangential velocity is maximum at the equator whereas zero at the poles.
 Sidereal Time:
lenth of day
360.98563°
=
One Sidereal day
360°
,for example, the length of the day for earth is 24 hr, so
sidereal time for the earth would be 23hr,56min,4sec.

8. Formulae
 Sidereal and Synodic relationship for Mercury and Venus:
1
P
=
1
E
+
1
S
 Sidereal and Synodic relationship for Mars, Jupiter, Saturn, Uranus, and Neptune
1
P
=
1
E
−
1
S
Where P is the sidereal planet of the planets, E is the sidereal period of the earth (23hr,56min,4sec or 1 day),
and S is the synodic period of the planets.

9. Interior of the Earth
Basically the internal layers of the earth have been divided into three layers, which
are Crust, Mantle, and Core. These layers are identified or classified by the
geophysical methods.
Crust is uppermost layer, Mantle is the middle layer and Core is the innermost layer.

11. Earth’s layer Classification
Chemical Layers Depths (km) Mechanical Layers Depths (km)
Crust Continental
Crust
35 to 40 km
70 km below root zone
Lithosphere 0 km to 100 or 150 km
Oceanic Crust 5-10 km
0 km at the center of MOR
Mantle Upper Mantle
Transition Zone*
35 km to 410 km Asthenosphere (LVZ)
Mesosphere
150 km to 250 or 300
km
250 or 300 km to 2900
km
410 km to 660 km
Lower Mantle 660 km to 2900 km
Core 2900 to 6367 km Barysphere Outer Core 2900 km to 5150 km
Inner Core 5150 km to 6367 km
* Transition Zone is the part of Upper Mantle

12. Behavior of the layers
Chemical Layers Minerals/Rocks/Elements Mechanical Layers Behaviors
Crust Continental
Crust
Granite, Granodiorite Lithosphere Brittle
(showing sandwich
model)
Oceanic Crust Basalt, Gabbro
Mantle
(Pyrolite
Compositon: 3
Dunite+ 1 Basalt)
Upper Mantle Peridotite, Eclogite, Olivine,
Spinel,Pyroxene, Perovskite, and
Oxides
Asthenosphere Plastic, Soft, Weak,
Horizontally flowing
layer
Transition Zone* Wadsleyite, Ringwoodite,
Perovskite, Magnesiowustite
Mesosphere Semi rigid
Lower Mantle
Core Fe+O, S, Ni-alloy Barysphere Outer Core Liquid
Inner Core Solid

13. Mechanical Layers and Thickness
Mechanical Layers Considered within Depths (km) Thickness (km)
Lithosphere Crust + Uppermost Upper
Mantle
0 km to 100 or 150 km 100 to 150 km
Asthenosphere (LVZ) Upper Mantle part 100 or 150 to 250 or 300 km 100 to 150 km
Mesosphere Remaining part of upper
mantle and whole lower
mantle
300 km to 2900 km 2600 to 2650 km
Barysphere Outer Core 2900 km to 5150 km 2250 km
Inner Core 5150 km to 6367 km 1217 km
LVZ: Low Velocity Zone

14. Chemical Layers and Thickness
Chemical
Layers
Depths Thickness
Crust Continental Crust Up to 35 or 40 km
Below root zone 70 km
Average 35 km
Oceanic Crust 5 to 10 km Average 5 km
Mantle Upper Mantle Uppermost Upper
Mantle
35 km to 410 km below
the continent
10 km to 410 km below
the oceanic crust
About 375 km to 400
km
Transition Zone 410 km to 660 km 250 km
Lower Mantle 660 km to 2900 km 2240 km
Core 2900 km to 6367 km 3467 km

15. Seismic Discontinuities
Seismic Discontinuities between Depths (km)
Conrad Discontinuity
(2nd Order Discontinuity)
Between Continental Crust (Upper
Crust) and Oceanic Crust(Lower
Crust)
11 km
Mohorovičić discontinuity Between Crust and Mantle 35 km below the continent
70 km below the root zone
5-10 km below the oceanic crust
No evidence in the MOR
Lehmann Discontinuity (LVZ) Between Lithosphere and
Asthenosphere
220 to 250 km
Gutenberg Discontinuity (D” layer)
ULVZ
Between Mantle and Core 2700 to 2900 km
Lehmann Bullen Discontinuity Between Outer Core and Inner
Core
5150 km
ULVZ: Ultra Low Velocity Zone

16. Some Facts
 Repetiti Discontinuity is found at the depth of 950 km which is marked as the lower limit of the very rapid rise in the
seismic velocity.
 The lower part of the lithosphere and the asthenosphere are the part of the Upper Mantle.
 410 km and 660 km discontinuities are occurred because of the breakdown of the minerals into the metal oxides
(MgO and FeO) and SiO2. Within which the velocity increases slightly.
At the depth of 410 km
Olivine , (Mg, Fe) 2 SiO4 Wadsleyite β − Spinel Structure
At the depth of 660 km
Wadsleyite  Ringwoodite γ − Spinel Strucutre  Perovskite Mg, Fe SiO3+ Magnesiowustite Mg, Fe O

17. Some Facts (Reason)
 Low Velocity Zone or Asthenosphere is the weak, soft, and plastic layer. This layer contains horizontally flow
magmas with < 1% of water. At the depth of 150 km to 200 km the rocks tends to melt partially (1000 to
1500°C) and the small amount of water is added. Because of the partial melting and adding of water, the
rock layer becomes more ductile in the influence of temperature. We know that the seismic velocity
depends upon the stiffness and density of the material, therefore the seismic velocity tends to decrease
gradually.
 Ultra Low Velocity Zone (D” layer) is the boundary between solid silicate rocks of the mantle and liquid Fe-Ni
alloy of the outer core. ULVZ is the extremely low velocity zone, the S-wave is reduced up to 30%. In this zone
the seismic velocity is tend to decrease because of changing in the phase i.e. density contrast.
 The outer core is identified by the S-wave, because the S-wave cannot travel though the liquid material.

18. P-wave and S-wave velocity ranges
Layers/Discontinuity/Depths 𝐕𝐏 𝐨𝐫 𝛂 (km/s) 𝐕𝐒 𝐨𝐫 𝛃 (km/s)
Lithosphere (up to 150 km) 6.0  8.0 3.0 5.0
Asthenosphere (up to 250 km) LVZ 8.0 7.5 (decreasing) 5.0 4.5 (decreasing)
Upper Mantle part below the
Asthenosphere (250 to 410 km)
7.5  10.0 4.5  6.0
Transition Zone (410 to 660 km) 10.0 9.0 (decreasing) 6.0 5.5 (decreasing)
Lower Mantle (660 to 2700 km) 9.0  14.0 5.5  8.0
ULVZ (D” layer 2700 to 2900 km) 14.0  7.8 (decreasing) 8.0 0.0 (decreasing)
Outer Core (2900 to 5150 km) 7.8 11.0 0.0
Inner Core ~11.0 ±4.0

19. Temperature Range
Layer Depth (km) Temperature (°C)
Lithosphere Up to 100 300 – 500
Upper Mantle
(Asthenosphere +
remaining parts)
Up to 400 1000 – 15000
Transition Zone 410 to 660 1900
Lower Mantle Up to 2900 3700
Outer Core Up to 5150 4300
Inner Core Up to 6367 6000

20. Density range (g/cc)
 The bulk density of Earth (5.5 g/cc) is the most among the all planets.
Layer Density (g/cc)
Continental Crust 2.7
Oceanic Crust 2.9
Upper Mantle 4.4
Lower Mantle 5.6
Outer Core 9.9 – 12.2 (density sharply
increased)
Inner Core 12.8 -13.1

21. Volume and Mass Percentages
Layer Volume % Mass %
Crust ~1.85 0.4
Upper Mantle 26.85 82.77 67.2
Lower Mantle 55.92
Outer Core 15.37 15.97 32.4
Inner Core 0.6
Volume Sequence: Lower Mantle > Upper Mantle > Outer Core > Crust > Inner Core
Mass Sequence: Mantle > Core > Crust

22. g-value variation with depths
Layer Depths (km) g-value (𝐦/𝐬 𝟐
)
Surface 0.0 9.83
Lithosphere 150 9.56
Asthenosphere 300 9.33
Upper Mantle 660 8.78
Lower Mantle 2900 5.33
Outer Core 5150 1.87
Inner Core 6367 0.00
Gravity breakdown
at 1200 km depths.
g-value with depth: gh = g(1 −
d
R
), where d is the
depth.

23. Bulk Chemical Composition
 Bulk Chemical Composition of the Earth’s Crust (wt.%)
O > Si > Al > Fe > Ca > Na > K > Mg
 Bulk Chemical Composition of the whole Earth (wt. %)
Fe > O > Si > Mg > Ni > S > Ca > Al > Na > Cr > Mn > Co > P > K > Ti