Earth has an equatorial bulge and polar flattening, with

equatorial radius (req) ~21 km greater

than the polar radius (rpole). The radius (r) of an equivalent sphere

is 6,371 km.

rpole

reqr = 6371 km)

Equivalentsphere

- 30 m

10 m

Based on satellite mapping,the earth is now known to betruly pear-shaped, in that, added to facts of earth’s equatorialbulge and polar flattening, the south pole is ~40 m closer to the earth’s center than the north pole.

Whole earth density is twice the average density of surface rocks,i.e., density must increase with depths inside the earth.

Solar radiation 173,410direct reflection 52,000direct conversionto heat 81,000evaporation 40,000water transport inoceans and atmosphere 370photosynthesis 40

Internal heat 32.3flow by conduction 32volcanism/hot springs 0.3

Power Flowon Earth’s Surface(trillion Joules per Second)

Inner core

Outer core

Mantle

2250 km63

71 k

m2900 km

Man

tle Lith

osph

ere

Continental crustOceanic crust

0 km

200 km

100 km

Earth is a multi-layered

body. This is based on the following evidences:

1. seismic2. gravity and

3. geomagnetic.

HydrogenHelium

OxygenCarbon

Nitrogen

SiliconNeon

MagnesiumIron

SulphurAluminum

CalciumNickel

SodiumArgon

ChromiumPhosphorous

ManganeseChlorine

PotassiumOther elements

HHe

OCN

SiNeMgFeSAlCaNiNaArCrPMnClK

74.50023.840

0.82000.37500.0910

0.08300.05500.05700.10400.03800.00660.00740.00920.00330.00300.00320.00090.00110.00060.0003

29.8

15.6

13.933.3

1.51.82.00.2

1.9

46.6

27.7

2.15.0

8.13.6

2.8

2.61.5

UniverseWholeEarth

Earth’sCrust

Outercore

The whole earth is richer in Fe, Mg and Ni, and poorer in Si, K and Al, than what

is found on the earth’s surface.

Whole Earth density = 5.5 gm/cm3

Density of the crust = 2.7 gm/cm3

Mantle

Co

re

CrustRo

ckyM

etallic Innercore

Columbia Earthquake, February 1999

The damages from January 17,

1994, Northridge earthquake

included1. collapse of Northridge Meadows

Apartments building that killed 16 people (one third of all the fatalities),

2. destruction of the parking garage at CSUN, and

3. damage to the overpasses of Interstate 5 near Castaic Junction

PS

Surface

Surface

PS

Seismogramfrom station A

Seismogram from station B

Time since the earthquake occurred

Distance from epicenter

Tim

e si

nce

th

e ea

rth

qu

ake

occ

urr

ed (

min

ute

s)

P waveshadow zone

P waveshadow

zone

P and S waves also yield information on the earth’s internal structure.

The P-wave “shadow zone” extends from 103o to 142o from the hypocenter, for instance, . . .

Outer core Inner core

. . . whereas the S-wave “shadow zone” extends beyond 103o from the hypocenter.

Seismograms atstations 103o to 142o from the hypocenterthus receiveno direct P or S waves from thatearthquake.

This occursbecause the fluid outer core prevents S waves traversing through it and slows the P waves down.

Los Angeles

Upsala130o34’

QuestionUpsala (59o52’N:17o38’E), Sweden, is located 130.57o from Northridge (34o14’N:118o38’W),

CA. Could we, then, have expected more reliable estimates of magnitude and related parameters

for January 17, 1994, Northridge earth-

quake from Upsala Seismological

Observatory than from the U.S. Geological

Survey at Denver, CO?

Cities with population of2 million by the year 2000Convergent or transformplate boundaries

300,000 90,000 10,000

Fatalities exceeding:Earthquake fatalities from AD 1000 to 1988

4 8 km/s0Seismic Wave VelocityCrust

LithosphereAsthenosphere

km

Source:M.S.T. Bukowinski:

Nature, Sept 30, 1999pp. 432-433

Estimated increase in temperature with depth in the Earth, as inferred from studies of volcanoes, seismic

wave velocities, laboratory experiments

and theory*.

Tem

per

atu

re (

°K)

Quaternary

ProterozoicAzoic or Archean

HolocenePleistocenePlioceneMioceneOligoceneEocenePaleocene

0

25

24375865

144208245286360408438505570

250038004700

Tertiary

CretaceousJurassicTriassicPermianCarboniferousDevonianSilurianOrdovicianCambrian

Phan

eroz

oic

Ceno

zoic

Pale

ozoi

cM

eso

-zoi

c

Earth’s evolution

Dinosaurs had dominated the Mesozoic life but vanished at the Cretaceous-Tertiary boundary without leaving any trace

10

40

30

20

010 30200 605040

Pb206/Pb204

Pb

207 /

Pb

204

4.54 Ga

Pb207

Pb204 = (0.6128+0.014)

+ (4.46+0.10)

Pb206

Pb204

The lead-lead isochron for meteorites

Evaporation320,000 km3

Ocean Storage1,370,000,000 km 3

Precipitation285,000 km3

Precipitation95,000 km3

Evaporation60,000 km3

Run-off: 35,000 km3

A conceptual look at the hydrological cycle