Wind Driven Plate Tectonics

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Wind Driven Plate Tectonics

Asim Mohamed Widatalla

Luleå University of Technology Master Thesis, Continuation Courses

Environmental Engineering

Department of Civil and Environmental Engineering Division of Renewable Energy

2007:082 - ISSN: 1653-0187 - ISRN: LTU-PB-EX--07/082--SE

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Dept. of Environmental Engineering

Wind Driven Plate Tectonics

Master thesis

Asim Mohamed Widatalla

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Widatalla Asim, LTU, 2007

Wind Driven Plate Tectonics

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Abstract

The objective of this project was to investigate if plate tectonics could be partly influenced by the dominating winds i.e. to investigate how predominate winds over the continents are correlated to tectonic plate movements.

This report presents the principle explanations and calculation methods to the hypothesis. The required data of the monthly mean wind velocity and the wind direction at 117 locations on the continents of the world were collected. By calculating the monthly mean wind force the resulting monthly force was calculated. The result indicates a relatively strong correlation between the plate movement and predominant wind in four out of five cases.

These results are mainly of scientific interest but could also be of interest for the climate change, since changing wind pattern would eventually affect the tectonic plate movements.

Key words: plate tectonics, wind velocity and direction, climate change effects

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Preface

While looking for a topic for the master thesis, I was planning to select a topic in renewable energy, I meet Professor Bo Nordell, where we discussed different things and topics, and he mentioned that he kept an idea for several years, in which he assumed that the plate tectonics may be influenced by the wind forces. Because my background is far from the earth sciences, it was the first time for me to know about this tectonics theory, so I was a little bit aware of that. But since still I should work in a senior design project in Renewable Energy, and this topic was suggested to be one of the options for that project, I planned to start and to give the final decision later.

After a while, I found that, I had the chance to see the whole world in a different view. Plates move in slow motion, this could be measured typically about 2 cm per year. I was supposed to investigate if the dominant wind could be among the factors that will affect this motion.

So at the end of the day, I found myself, spent not only a single course period, but most of the winter and spring in front of a computer, selecting different cites and locations all around the five continents, drawing maps, analyzing the data, correlating the results with the actual movement of the plates, and trying to come up with amazing conclusion, this is quite a challenging thing to do. Even though I am glad this period is now over, it has been a very interesting learning process to go through, which has been facilitated by quite a few people whom I would like to thank:

◙ Professor Bo Nordell for his friendly and fruitful way of supervision, and for giving the constructive feedback and comments;

◙ My beloved parents – who they ever believe in science and knowledge- for their continuous supporting, caring, prayers, and still they are encouraging me to go further.

◙ Hisham my brother for being a part of every nice step in my life;

◙ Reem my wife for taking the right decision at the difficult time, studying the nanophysics, and caring of our kids, giving me the strength and a reason to overcome challenges and achieve things.

◙ To Mohamed and Omer my sons, for giving the real meaning and lovely taste to the life, and making me look at the future as a world of possibilities.

◙ Finally, I would like to thanks my sisters, relatives and friends, especially those who spent the nights praying for me, and those who keep thinking of me and believing that, I will do it.

My thanks will ever be at the beginning and the end to Allah who said:

……….. ‘‘And when your Lord made it known: If you are grateful, I would certainly give to you more, and if you are ungrateful, My chastisement is truly severe’’

……….. (14:7)

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Table of Content

Abstract ... 3

Preface ... 5

Table of Content... 7

List of Figures ... 8

List of Tables... 9

1 BACKGROUND... 10

1.1 Plate Tectonics ... 10

1.2 Major plates... 11

1.3 Climate Change ... 11

2 OBJECTIVES ... 12

3 METHOD... 13

3.1 The force Equation: ... 13

3.2 The Torque Equations ... 13

4 PROCEDURE AND RESULTS ... 14

4.1 General ... 14

4.2 Australia ... 14

4.2.1 Overall Site method... 15

4.2.2 Overall Time method ... 17

5 DISCUSSION AND SUMMARY ... 19

5.1 General: ... 19

5.2 Australia ... 19

6 CONCLUSION ... 22

7 REFERENCES... 24

APPENDIX ... 25

A: South America:... 25

B: North America ... 32

C: Africa ... 40

D: Eurasia... 48

REFERENCES:... 54

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List of Figures

Figure 1: Major and minor tectonics plates of Earth [UPRM, 4]... 11

Figure 2: Simplified picture illustrating the wind over land. ... 13

Figure 3: Location of selected 20 sites and area center of Australia... 14

Figure 4: The Australian plate, center of continent (Alice Springs) and centre of plate [ESUM, 10] ... 19

Figure 5: Monthly wind force over Australia... 20

Figure 6: Monthly wind force direction over Australia. ... 20

Figure 7: The arrows indicate the actual and calculated direction of the Australian plate movement, [ESUM, 10] ... 21

Figure 8: Major plates, plate boundaries, and plate movements. [Christopherson, 11]... 21

Figure 9: Digital Tectonics Activity Map - plate boundaries - plate movements. [NASA

, 12

]... 22

Figure 10: Location of selected 21 sites and mass center of gravitation, South America. ... 25

Figure 11: South American plate and the location of Sao Carlos city, the area center of the continent, and the suggested location of the center of the plate, [USGS, 13]... 29

Figure 12: Calculated monthly wind force of South America. ... 30

Figure 13: Calculated monthly wind force direction of South America. ... 30

Figure 14: Actual and calculated direction of the South American plate movement. [USGS, 13]... 31

Figure 15: Location of the selected 30 sites in North American. [Theodora, 14]... 32

Figure 16: The North America plate and the location of International Falls city, the area center of the continent, and the suggested location of the center of the [15]... 37

Figure 17: Total monthly wind force in North America. ... 37

Figure 18: Monthly wind force direction over North America... 38

Figure 19: Actual and calculated direction of the North American plate movement. [15]... 38

Figure 20: Modified map of San Andreas Fault, [16] ... 39

Figure 21: Location of the selected 29 sites in Africa, [ABC, 17]... 40

Figure 22: The African plate, Africa and the location of Yangambi city the area center of the continent, and the suggested location of the center of the plate [18]. ... 45

Figure 23: Calculated monthly wind force in Africa. ... 46

Figure 24: Calculating wind force direction in Africa over the year. ... 46

Figure 25: Actual and calculated direction of the African plate movement [18]... 47

Figure 26: Location of the selected 18 sites on the Eurasian continent [19] ... 48

Figure 27: The Eurasian plate and its center at Ekibastuz city, the area center of the continent, and the suggested location of the center of the plate [19] ... 52

Figure 28: Calculated monthly wind force over the year... 52

Figure 29: Calculated wind force direction over Eurasia during the year. ... 53

Figure 30: Actual and calculated direction of the Eurasian plate movement [19]. ... 53

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List of Tables

Table 1: Calculated wind force and wind direction at specific sites... 15

Table 2: Calculated overall wind force for different sites. ... 16

Table 3: Calculated wind force in Australia (January). ... 17

Table 4: The overall wind force based on monthly resultant force calculation. ... 18

Table 5: Results of the Overall Site and Overall Time methods for Australia... 20

Table 6: Summary of calculated wind force, torque, actual plate movement of major plates... 23

Table 7: Calculated monthly wind force and wind direction at Vladivia-Pichoy ...Erreur ! Signet non défini. Table 8: Calculated wind force and direction at difference locations in South America... 27

Table 9: Calculated wind force for a specific month (South America). ... 28

Table 10: Resulting overall wind force based on monthly data, South America. ... 28

Table 11: Results of the Overall Site and Overall Time methods for South America. ... 29

Table 12: Calculated wind force and direction at a specific site (Astoria)... 33

Table 13: Overall wind force and direction based on site calculations. ... 34

Table 14: Calculated wind force in North America for January. ... 35

Table 15: Calculated overall wind force based on monthly force calculations. ... 36

Table 16: Overall Site and Time methods (North America). ... 36

Table 17: Calculated monthly wind force and wind direction at ‘Port Sudan’. ... 41

Table 18: Overall wind force in Africa based on the sites calculation. ... 42

Table 19: The wind force calculation in a specific month (Africa) . ... 43

Table 20: The overall wind force based on monthly resultant force calculation. ... 44

Table 21: The results of the Overall Site and Time methods (Africa)... 45

Table 22: Calculated wind force at Bolsoj Santar. ... 49

Table 23: The overall wind force based on monthly resultant force calculation. ... 49

Table 24: Show the calculation of the wind force in a specific month (January) ... 50

Table 25: The result of the overall Site and Time methods (Eurasia). ... 51

Table 26: The results of the Overall Site and Time methods (Eurasia)... 51

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1 BACKGROUND

1.1 Plate Tectonics

Plate Tectonics is the theory that provides an explanation for the behaviour of the Earth's crust, particularly the global distribution of mountain building, earthquake activity, and volcanism in a series of linear belts. Numerous other geological phenomena such as lateral variations in surface heat flow, the geology of ocean basins, and various associations of igneous, metamorphic, and sedimentary rocks can also be logically related by plate tectonics theory.

The theory of plate tectonics arose out of two separate geological observations: continental drift, noticed in the early 20

^th

century, and seafloor spreading, noticed in the 1960s. The theory itself was developed during the late 1960s and has since been universally accepted by virtually all scientists. It has revolutionized the earth sciences and, because of its unifying and explanatory power for diverse geological phenomena, and because it was very successful at predicting many features of Earth's crust. Essential features of the plate tectonics hypothesis are widely accepted [Keith 2001, 1] ; but even so, some geologists were not satisfied until the slow motion of the plates could be measured typically about 2 cm per year. This was accomplished in the 1980s using satellites, lasers, and the positions of very distant galaxies.

The main features of plate tectonics are:

• The surface of Earth consists of several lithospheric plates; the plates encompass the crust

and the upper mantle.

• Plate boundaries are of four types: midocean ridges where new material is added to the

plates, subduction zones where denser and more ductile parts of plates are destroyed, transform faults where plates slide past another, and basal viscous shear zones along which motion between the base of lithospheric plates and underlying mantle (asthenosphere) occurs.

• Convection currents beneath the plates move the lithospheric plates in different directions.

• The energy source driving the convection currents is radioactivity of Earth’s mantle.

Convection is also driven by density contrasts of the Earth.

The Plate Tectonics theory asserts that Earth is divided into core, mantle, and crust. The crust is subdivided into oceanic and continental crust. This theory is based on a simple model of the Earth in which a rigid outer shell of 50–150 km thick, the lithosphere, consisting of both oceanic and continental crust as well as the upper mantle, is considered to lie above a hotter, weaker semi-plastic asthenosphere. The asthenosphere extends from the base of the litho- sphere to a depth of about 700 km.

The important geologic theory of plate tectonics asserts that the Earth's surface is composed

of about seven major blocks, or plates, and many more minor plates that move across the

Earth's surface at a very slow rate. Although the plates creep along at a rate of just cm per

year, this movement still causes stress and strain in the Earth's crustal structure. These shifting

plates cause faults, mountains, trenches, mid-oceanic ridges and rifts, and even ocean basins,

some movements may result in violent earthquakes and volcanic eruptions. The theory is

explaining geologic changes that result from the movement of litho-spheric plates over the

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asthenosphere. The visible continents, a part of the lithospheric plates upon which they ride, shift slowly over time as a result of the forces driving plate tectonics.

Plate tectonics is the surface expression of mantle convection driven by radiogenic heat [Dickinson 1981, 2] and the plates are able to move because of the relative weakness of the asthenosphere. Dissipation of heat from the mantle is acknowledged to be the source of energy driving plate tectonics. Three-dimensional imaging of the Earth's interior indicates that, convection of some sort is occurring throughout the mantle [Tanimoto 2000, 3].

Somehow, this energy must be translated to the lithosphere in order for tectonic plates to move. There are essentially two forces that could be accomplishing this: friction and gravity.

1.2 Major plates

The main plates as shown in the map in Figure 1 below are:

1.

African Plate, covering the African Continent.

2.

Antarctic Plate, covering the Antarctican Continent.

3.

Australian Plate, covering the Australian Continent.

4.

Eurasian Plate covering the Eurasia Continent.

5.

North American Plate covering the North American Continent and north-east Siberia.

6.

South American Plate covering the South American Continent.

7.

Pacific Plate, covering the Pacific Ocean.

Notable minor plates include the Indian Plate, the Arabian Plate, the Caribbean Plate, and the Scotia Plate.

Figure 1: Major and minor tectonics plates of Earth [UPRM,4].

1.3 Climate Change

Climate change refers to the variation in the Earth's global climate or regional climates over

time. It describes changes in the variability or average state of the atmosphere over time

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scales ranging from decades to millions of years. These changes may come from internal processes, be driven by external forces or, most recently, be caused by human activities.

In recent usage, especially in the context of environmental policy, the term "climate change"

is often used to refer only to the ongoing changes in modern climate, including the rise in average surface temperature known as global warming.

The global climate change has large implications for both humans and wildlife. Many threatened and endangered species, which already lead a precarious existence, are likely to suffer further declines. It’s checked clearly that the climatic changes have significantly affected natural ecosystems in many regions of the world. These changes include alterations in plant community structure, composition, biological productivity, biodiversity and spatial patterns [Wang et al. 2007, 5].

Global warming also threatens populations of species that were once relatively secure, and is likely to result in the endangerment of more species in the future. A study of habitats comprising 20 percent of the earth's surface suggested that 15 to 37 percent of the world's species may be extinct by 2050 if recent warming trends continue [Pounds et al, 2004, 6] and the alterations in these ecosystems lead to dramatic changes in soil physical properties, soil and surface water dynamics and in the soil carbon cycle, which in turn exert a profound influence on the entire biosphere [Christensen et al., 2004, 7] and [Wang et al. 2007, 5].

Earth's climate is a delicate balance of energy input, chemical and biological processes, and physical phenomena. The Earth's atmosphere plays a critical role in planetary surface temperature. Some gases, such as carbon dioxide (CO

2

) and methane (CH

4

), absorb and maintain heat in the same way that glass traps heat in a greenhouse. These greenhouse gases in Earth's atmosphere allow temperatures to build up, keeping the planet warm and habitable to the life forms that have evolved here. This phenomenon is called the greenhouse effect.

This study is based on the idea that plate tectonics could be party influenced by dominating winds, i.e. the resulting wind force on the different plates. As a consequence the ongoing climate change and possible changes in wind direction and wind velocities might change the movements of the plates.

2 OBJECTIVES

The aim of this initial study is to investigate if there is any correlation between plate movements and predominant wind directions. More specifically the aim is to investigate:

1- To analyse the global wind directions and the wind velocities.

2- To calculate resulting wind force in order to check the influence of that force on the Plate Tectonics movements.

3- To correlate the resulting wind force with the plate movement.

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3 METHOD

3.1 The force Equation:

The wind causes a skin friction on the ground surface. According to [Taylor 1916, 8], if it were possible to measure the tangential force exerted by the wind as it blows over a large tract of land, it should be equal to the skin friction on a similar small surface when subjected to the action of the very high wind.

So, to reduce the tract of land to a similar small flat plate, the trees and houses would be reduced to a mere roughness on the plate. It is to be expected, if the skin friction on unit area of the earth's surface, the wind force, F (N/m

²

), can be expressed

Figure 2: Simplified picture illustrating the wind over land.

.

F = kρQ² (1)

Where Q is the wind velocity near the surface (m/s), ρ is the density of the air assumed to be 1.29 Kg/m³, and according to: G. I. Taylor (1916), the value of the skin friction coefficient k will be the same as the constant which would be found in the laboratory by experimenting with a small, slightly roughened plate.

So since the actual values of the skin friction coefficient k are of the same order of magnitude, but probably somewhat smaller than those found in the laboratory, being 0.002 to 0.003 as against the value 0.004 found for skin friction in a pipe, so we assumed the value of the constant to be 0.003.

3.2 The Torque Equations

Torque is known as the application of force where there is rotational motion, and it can be expressed according to the following relation:

T=F

_tot

*r (2)

Where F

tot

is the total force on the specific continent (resulting force per m² x area of the

continent) attached in centre, and r is the perpendicular (or smallest) distance to the mass

center of the plate. Here we are assuming that the mass center is equivalent to the area center.

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4 PROCEDURE AND RESULTS

4.1 General

The wind data were investigated at many locations, selected all around each continent, as shown by the maps illustrating chosen locations (see blow), Monthly wind data of the selected points were determined by using the METEONORM Version 5.1 software [Meteonorm, 2007, 9].

The different locations in each continent or plate were selected randomly, but the basic idea behind the selection is that:

1- Evenly distributed on all sides of the continent.

2- The selection of the specific locations is to give an idea of the actual effects of the wind forces on the specific continent and the specific plate.

Two calculations methods have been used to determine the wind force in this study; In the Overall Site Method the overall annual wind force of the sites was used as the basic data for the final overall result. In the Overall Time Method the overall monthly wind force was used as the basic data for calculating the final overall result.

4.2 Australia

For the analytical study of the Australian plate, the wind data were investigated at twenty locations all around Australia, as shown in Figure

3

.

Alice Springs city which located at the center of the Australian continent, assumed as the area center of the continent.

Figure 3: Location of selected 20 sites and area center of Australia.

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4.2.1 Overall Site method

Based on the above equation and assumptions, for each of the twenty sites, the wind force and direction was calculated, to show the calculation process here below is Carnarvon Airp site mentioned as example.

Table 1: Calculated wind force and wind direction at specific sites.

Site: Carnarvon Airp.

Month Wind Speed Wind Direction F (N/m2) Fy (N/m2) Fx (N/m2)

Jan 7.5 194 0.22 0.2 0.1

Feb 6.9 197 0.18 0.2 0.1

Mar 6.5 212 0.16 0.1 0.1

Apr 5.2 230 0.10 0.1 0.1

May 4.5 207 0.08 0.1 0.0

Jun 4.3 229 0.07 0.0 0.1

Jul 4.4 224 0.07 0.1 0.1

Aug 4.9 231 0.09 0.1 0.1

Sep 6.1 214 0.14 0.1 0.1

Oct 7 211 0.19 0.2 0.1

Nov 7.3 198 0.21 0.2 0.1

Dec 7.8 185 0.24 0.2 0.0

Yearly mean 6.0 211 0.147 0.128 0.063

Wind Direction 206.3 Wind Force 0.143

By calculating the wind force and wind direction of each location, we can get the overall wind

force and wind direction.

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Table 2: Calculated overall wind force for different sites.

Location Wind Force Wind Direction Fy= F*COS(Θ-180) Fx= F*SIN(Θ-180)

Carnarvon Airp 0.143 206.3 0.13 0.06

Sheoaks Aws 0.003 180.2 0.00 0.00

Elcho island 0.001 90.7 0.00 0.00

Double IsI pT 0.194 195.9 0.19 0.05

Mallacoota Aws 0.036 136.2 0.03 -0.02

Adele isi awa 0.019 125.9 0.01 -0.02

thursday/hall 0.013 128.6 0.01 -0.01

Gooseberry Hill 0.118 255.5 0.03 0.11

Williamtown Airp 0.024 245.5 0.01 0.02

Thangool 0.011 127.3 0.01 -0.01

Learmonth airp 0.042 120.9 0.02 -0.04

Mt Gambier 0.017 180.3 0.02 0.00

Lancelin 0.074 246.4 0.03 0.07

Esperance 0.004 223.7 0.00 0.00

Cooktown Mission 0.071 167.6 0.07 -0.02

Greater Wollongo 0.042 208.9 0.04 0.02

Swanburne Aws 0.112 252.8 0.03 0.11

Albany Airp 0.002 152.1 0.00 0.00

Naracoorte 0.018 213.9 0.01 0.01

Green Island 0.23 167.7 0.22 -0.05

0.043 0.015

Wind Direction 199.2

Wind Force 0.046

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4.2.2 Overall Time method

Since the wind varies in velocity and direction over the year the effect of the wind force on the different sites was studied during each month, as the calculations procedure and the results shown for the first month of the year in the table below

Table 3: Calculated wind force in Australia (January).

Location Wind ForceWind Force Wind ForceWind Force Wind Direction Fy= F*COS(Θ-180) Fx= F*SIN(Θ-180)

Carnarvon Airp 0.22 194 0.21 0.05

Sheoaks Aws 0.09 180 0.09 0.00

Elcho island 0.01 270 0.00 0.01

Double IsI pT 0.25 188 0.25 0.03

Mallacoota Aws 0.09 90 0.00 -0.09

Adele isi awa 0.08 293 -0.03 0.07

thursday/hall 0.02 315 -0.01 0.01

Gooseberry Hill 0.19 213 0.16 0.10

Williamtown Airp 0.07 180 0.07 0.00

Thangool 0.02 120 0.01 -0.02

Learmonth airp 0.14 293 -0.05 0.13

Mt Gambier 0.1 180 0.10 0.00

Lancelin 0.12 213 0.10 0.07

Esperance 0.13 90 0.00 -0.13

Cooktown Mission 0.04 168 0.04 -0.01

Greater Wollon. 0.07 180 0.07 0.00

Swanburne Aws 0.14 213 0.12 0.08

Albany Airp 0.07 90 0.00 -0.07

Naracoorte 0.06 225 0.04 0.04

Green Island 0.16 168 0.16 -0.03

0.054 0.005

Wind Force Wind Force Wind Force

Wind Force 0.054 Wind direction Θ

Wind direction Θ Wind direction Θ

Wind direction Θ 364.7

Based on the above results of January and the results of the rest months of the year, one can

observe the overall effect of the wind force from the different locations around Australia,

through the year. This can be calculated easily by the following procedure, where the wind

force and the angle of direction of each month were used as basic data, and then both the

overall resultant force and the angle of direction can be calculated as an average value:

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Table 4: The overall wind force based on monthly resultant force calculation.

Month

Wind Force

Wind

Direction PI/180

Fy=F*COS(Θ- 180)

Fx=F*SIN(Θ- 180)

Jan 0.054 364.7 0.017456 -0.05 0.00

Feb 0.042 314.3 0.017456 -0.03 0.03

Mar 0.044 222.3 0.017456 0.03 0.03

Apr 0.045 315 0.017456 -0.03 0.03

May 0.038 297.3 0.017456 -0.02 0.03

Jun 0.023 292 0.017456 -0.01 0.02

Jul 0.021 252.7 0.017456 0.01 0.02

Aug 0.011 174.9 0.017456 0.01 0.00

Sep 0.013 227.7 0.017456 0.01 0.01

Oct 0.022 187.6 0.017456 0.02 0.00

Nov 0.039 179.6 0.017456 0.04 0.00

Dec 0.035 172.1 0.017456 0.03 0.00

0.001 0.014

¹⁶

Nm

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5 DISCUSSION AND SUMMARY

5.1 General:

By using the calculation procedures, and the results mentioned above, it will be possible to analyse the global wind directions and the wind velocities, and this will lead to the calculation of the resulting wind force needed for investigating its influence on the different plate tectonics movement.

As shown in the calculation procedure, there two different ways of calculations were used.

The Overall Site method is based in the overall annual wind force of the site. In the second method, the Overall Time Method, the overall monthly wind force is the basic data of the final overall result. By using the second method we will be able to recognize the seasonal variation of the wind force.

As mentioned above, the main objectives behind the study are to correlate the resulting wind force with the plate movement. The actual direction of plate movement is seen in Figure 7.

5.2 Australia

The force of the Overall Site Method was used to calculate the torque of the wind force. Here Over which depend on the assumption of a specific location as a centre of gravitation and by measuring the distance of each location from this centre and according to the first relation that mentioned previously, we can calculate the overall torque, the location of the centre of gravitation shown in Figure 4 below.

Figure 4: The Australian plate, center of continent (Alice Springs) and centre of plate [

ESUM,

10]

Based on the result of the second method of calculation – the Overall Time Method – Figure 5

illustrates the different wind force value of each Month. From the graph it can be seen that the

greatest wind force over the Australian plate occurs during January – 0.048 N/m²- while the

lowest wind force value occurs in September where the value used to reach 0.012 N/m².

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The results of the wind force and the wind angle of direction based on the two methods of calculations, beside the wind torque results were shown here in the table below:

Table 5: Results of the Overall Site and Overall Time methods for Australia Method Overall Site Method Overall Time Method

Wind Force 0.046 N/m² 0.014 N/m²

Wind Direction 199.2 º 265.7 º

Wind Torque -8.91^.10¹⁶ Nm

0 0.01 0.02 0.03 0.04 0.05 0.06

Wind force N/m2

Jan Mar May Jul Sep Nov

Months

Wind Force

Figure 5: Monthly wind force over Australia.

The corresponding wind force directions through the year are shown in Figure 6.

Wind force direction

0 50 100 150 200 250 300 350 400

0 2 4 6 8 10 12 14

Months

Angle of direction

Figure 6: Monthly wind force direction over Australia.

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So from the calculated wind force direction that mentioned above in table 26, where the angle of direction is between 199.2 and 265.7 - that can be illustrated in the map as in the figure 10 below - if we compare that with the actual movement of the Australian plate as shown in the map from After Christopherson (1997), figure 11, we will find the same direction of movement of the plate.

Figure 7: The arrows indicate the actual and calculated direction of the Australian plate movement, [ESUM, 10]

Figure 8: Major plates, plate boundaries, and plate movements. [Christopherson, 11]

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5.3 SUMMARY

The described calculation methods of the wind, wind force and torque used for the Australian plate were applied on the rest of the major plates (South America, North America, Africa and Eurasia). The resulting wind forces were correlated with the size of the actual movement of these plates based on the data of Digital Tectonics Activity Map of the Earth in Figure 9. A summary of these results are given in Table 6.

All the details of the calculations processes are available in the Appendices A, B, C and D.

Figure 9: Digital Tectonics Activity Map - plate boundaries - plate movements. [NASA, 12].

6 CONCLUSION

As seen in the Table 6, the correlation of the calculated force of the wind direction of North

America is almost the same as the actual plate movement, where the difference in the angle of

direction is 7.3

^o

. The difference in the angles of direction for South America reach 16.4

^o

,

even the plates of Eurasia and Africa based on the above correlation were found in directions

near to the actual movement directions of these plates, but the difference in the angles of

direction was found 37.8

^o

and 93.8

^o

respectively.

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Table 6: Summary of calculated wind force, torque, actual plate movement of major plates.

Calculated wind force data Difference

Force (N/m²) Torque (Nm)

Wind force direction Θ1

Plate movement

Θ2

mm per year

Θ1- Θ2 Australia 0.014-0.046 -8.91 ^.10¹⁶ 199.2-265.7 230 72 30.8-35.7 South

America 0.022-0.047 -1.17 ^.10¹⁵

55.0-73.6 90 35 35.0-16.4

North

America 0.0075-0.021 4.3 ^.10¹⁵

210.0-187.3 180 35 7.3- 30.0

Africa 0.007-0.025 1.66 ^.10¹⁶ 176.2-152.8 270 33 93.8

Eurasia 0.019-0.023 7.34 ^.10¹⁶ 376.2-352.8 315 19 37.8-61.2

The wind velocity values are not random, but the random selection of the locations from all around a specific plate, will not give enough data, which will reflect a very clear view of the actual situation of the effect of the wind force.

The angle of direction for the wind force that obtained from the study for the all five plates is closer to the actual movement direction of these plates, where the difference varies from plate to other.

Both methods show that, even the result value of the wind force at the study is small, but the

influence of the wind force on the plate tectonics movements, expected to be higher, if the

wind velocities increased due to any reasons such as the global climate change.

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7 REFERENCES

1. MacKenzie, Keith, Evidence for a plate tectonics debate, Earth-Science Reviews 55 2001 235–336.

2. W. R. Dickinson, Plate tectonics through geological time, Phil. Trans. R. SOG.LOIUI.

A 301, 207-215 (1981).

3. Tanimoto, Toshiro and Thorne Lay (2000) Mantle dynamics and seismic tomography, Proc. Natl. Acad. Sci. USA, Vol. 97, No. 23 (Jan. 1, 1916), pp. 12409-12410.

4. The website of Universidad de Puerto Rico - Mayagüez, http://geology.uprm.edu/Morelock/1_image/plate.jpg

5. Genxu Wang a,c, Yibo Wang b, Yuanshou Li c, Huiyan Cheng, Influences of alpine ecosystem responses to climatic change on soil properties on the Qinghai–Tibet Plateau, China. Catena 70 (2007) 506–514.

6. J. Alan Pounds and Robert Puschendorf, Clouded futures, NATURE, 2004.

http://www.nature.com/nature/journal/v427/n6970/pdf/427107a.pdf et al, 2004 7. Christensen, T.R., Johansson, Torbjom, Akerman, Jonas H., Masterpanov, Mihail,

2004. Thawing sub-arctic permafrost: effects on vegetation and methane emissions.

Geophysical Research Letters 31, L04501.

8. G. I. Taylor (1916) Skin Friction of the Wind on the Earth's Surface, Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, Vol. 92, No. 637 (Jan. 1, 1916), pp. 196-199.

9. Meteonorm, 2007. The Meteonorm Model.

http://software.cstb.fr/soft/present.asp?page_id=us!meteonorm

10. ESUM The website of the School of Earth Sciences-University of Melbourne - Australia http://web.earthsci.unimelb.edu.au/antarctica/plateTectonics.html 11. Christopherson. R.W., 1997. Geosystems, 3

^rd

Ed. Prentice Hall corp. Upper Saddle

River, NJ. 656 pp.

12. NASA, Planetary Geodynamics Laboratory at the National Aeronautics and Space Administration. http://denali.gsfc.nasa.gov/dtam/data/ftp/dtam.jpg

13. USGS, The website of the U.S. Geological Survey, http://pubs.usgs.gov/publications/text/slabs.html

14. The popular educational web site of Information Technology Associates (ITA).

http://www.theodora.com/maps/

15. The Zetatalk website, http://www.zetatalk.com/info/tinfo05t.htm 16. Geology, http://geology.com/articles/images/san-andreas-fault-map.jpg 17. ABC, The ABC teach website, http://www.abcteach.com/Savannah/map.htm 18. The Zetatalk website, http://www.zetatalk.com/info/tinfo05r.htm

19. The Zetatalk website, http://www.zetatalk.com/info/tinfo05s.htm

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APPENDIX

A: South America:

For the analytical study of the South American plate, the wind data were investigated at twenty-one locations, all around South America, as shown in figure 6.

Ji-Parana BR city which located at the center of the South American continent, assumed as the area center of the continent.

Figure 10: Location of selected 21 sites and mass center of gravitation, South America.

Overall Site method

Based on the above equations and assumptions, for each of the twenty-one sites, the wind

force and direction was calculated, to show the calculation process here below is Vladivia-

Pichoy site mentioned as example.

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Table 7: Calculated monthly wind force and wind direction at Vladivia-Pichoy .

Month Wind Speed Θ F (N/m2) Fy (N/m2) Fx (N/m2)

Jan 3.4 180 0.04 0.0 0.0

Feb 3.1 180 0.04 0.0 0.0

Mar 2.6 180 0.03 0.0 0.0

Apr 2.1 0 0.02 0.0 0.0

May 2 0 0.02 0.0 0.0

Jun 2.6 0 0.03 0.0 0.0

Jul 2.6 0 0.03 0.0 0.0

Aug 2.8 0 0.03 0.0 0.0

Sep 2.9 0 0.03 0.0 0.0

Oct 3 0 0.03 0.0 0.0

Nov 3.1 180 0.04 0.0 0.0

Dec 3.2 180 0.04 0.0 0.0

Yearly mean 2.783 75.000 0.031 0.000 0.000

Wind Direction 172.9

Wind Force 0.000

By calculating the resulting wind force and direction at different locations (e.g. Table 8), we

can easily get the overall wind force, direction and torque, as shown in Table 9.

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Table 8: Calculated wind force and direction at difference locations in South America.

Location Wind ForceWind ForceWind ForceWind Force Wind Direction Fy= F*COS(Θ-180) Fx= F*SIN(Θ-180)

Vladivia-Pichoy 0 172.9 0.00 0.00

Concepcion 0.03 239.8 0.02 0.03

Arica-Shacalluta 0.027 253.2 0.01 0.03

San Juan de Marcona 0.041 180 0.04 0.00

Lima 0.064 180 0.06 0.00

Islotes Evangelista 0.49 258 0.10 0.48

Esmeraldas EC 0.04 180.1 0.04 0.00

Cali/Alfonso Bonill 0.005 180.1 0.00 0.00

Simon Bolivar Airp. 0.086 206.6 0.08 0.04

Caracas/La Carlota 0.018 258.1 0.00 0.02

Mabaruma 0.018 248.1 0.01 0.02

Cayenne-Rochea 0.063 263.6 0.01 0.06

Sao Luiz 0.061 90 0.00 -0.06

Macau 0.071 92.1 0.00 -0.07

Loao Pessoa 0.038 92.2 0.00 -0.04

Salvador 0.093 94.9 0.01 -0.09

Punta Del Este 0.131 253 0.04 0.13

Viedma-Castello 0.139 256.2 0.03 0.13

Comodoro Rivadavi 0.144 112.9 0.06 -0.13

Rio Gallegos Airp 0.172 258 0.04 0.17

Ushuaia Airp 0.112 258 0.02 0.11

0.027 0.039

Wind Force 0.047 Wind direction Θ 55.0

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Overall Time Method

Table 9: Calculated wind force for a specific month (January).

Location Wind ForceWind ForceWind ForceWind Force Wind Direction Fy= F*COS(Fy= F*COS(Fy= F*COS(Fy= F*COS(Θ-180)

Fx= F*SIN(

Fx= F*SIN(Fx= F*SIN(

Fx= F*SIN(Θ- 180)

Vladivia-Pichoy 0.04 180 0.04 0.00

Concepcion 0.08 225 0.06 0.06

Arica-Shacalluta 0.04 248 0.01 0.04

San Juan de Marcona 0.06 180 0.06 0.00

Lima 0.08 180 0.08 0.00

Islotes Evangelista 0.6 258 0.13 0.59

Esmeraldas EC 0.06 0 -0.06 0.00

Cali/Alfonso Bonill 0.01 0 -0.01 0.00

Simon Bolivar Airp. 0.13 23 -0.12 -0.05

Caracas/La Carlota 0.02 78 0.00 -0.02

Mabaruma 0.02 68 -0.01 -0.02

Cayenne-Rochea 0.07 68 -0.03 -0.06

Sao Luiz 0.06 90 0.00 -0.06

Macau 0.06 90 0.00 -0.06

Loao Pessoa 0.03 90 0.00 -0.03

Salvador 0.1 90 0.00 -0.10

Punta Del Este 0.12 78 -0.02 -0.12

Viedma-Castello 0.2 248 0.07 0.19

Comodoro Rivadavia 0.21 293 -0.08 0.19

Rio Gallegos Airp 0.24 258 0.05 0.23

Ushuaia Airp 0.15 258 0.03 0.15

0.009 0.044

Based on the above results of January and the results of the rest months of the year, one can observe the overall effect of the wind force from the different locations around South America, through the year as shown below:

Table 10: Resulting overall wind force based on monthly data, South America.

Month Wind ForceWind ForceWind ForceWind Force Wind Direction Fy= F*COS(Fy= F*COS(Fy= F*COS(Fy= F*COS(Θ-180) Fx= F*SIN(Fx= F*SIN(Fx= F*SIN(Fx= F*SIN(Θ-180)

Jan 0.045 257.9 0.01 0.04

Feb 0.027 257.7 0.01 0.03

Mar 0.022 256.2 0.01 0.02

Apr 0.022 263.6 0.00 0.02

May 0.018 100.6 0.00 -0.02

Jun 0.013 110.9 0.00 -0.01

Jul 0.027 265.7 0.00 0.03

Aug 0.021 248.3 0.01 0.02

Sep 0.021 256.4 0.00 0.02

Oct 0.026 255.7 0.01 0.03

Nov 0.04 253.2 0.01 0.04

Dec 0.038 254 0.01 0.04

0.006 0.021

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Method Overall Site Method Overall Time Method

Wind Force 0.047 N/m² 0.022 N/m²

Wind Direction 55.03 º 73.6 º

Wind Torque

-1.17

^.

10

¹⁵Nm

The first method was used to calculate the torque of the wind force which depend on the assumption of a specific location as a centre of gravitation and by measuring the distance of each location from this centre and according to the first relation that mentioned previously, we can calculate the overall torque, the location of the centre of gravitation shown in Figure (11) below.

Figure 11: South American plate and the location of Sao Carlos city, the area center of the continent, and the suggested location of the center of the plate, [USGS, 13]

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Based on the result of the second method of calculation – the Overall Time Method – Figure (12) illustrates the different wind force value of each month. From the graph it can be seen that the greatest wind force over the South American plate occurs during the winter season from November to January 0.035 – 0.04 N/m²- while the lowest wind force value occurs in June where the value used to reach 0.014 N/m².

Wind Force

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Months

Wind Force (N/m2)

Figure 12: Calculated monthly wind force of South America.

The corresponding wind force directions through the year are shown in Figure below.

Wind Force direction

0 50 100 150 200 250 300

0 2 4 6 8 10 12 14

Months

Degrees

Figure 13: Calculated monthly wind force direction of South America.

So from the calculated wind force direction that mentioned above in table 11, where the angle

of direction is between 55.03 and 73.6 - that can be illustrated in the map as in the figure (14)

below -, if we compare that with the actual movement of the Australian plate as shown in the

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map from After Christopherson (1997), figure (8) above, we will find the same direction of movement of the plate.

Figure 14:Actual and calculated direction of the South American plate movement.[USGS, 13]

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B: North America

For the analytical study of the North American plate, the wind data were investigated at twenty nine locations, all around North America, as shown here below in figure 4.

International Falls station, which located at the center of the North American continent, was assumed as the area centre of the continent.

Figure 15: Location of the selected 30 sites in North American. [Theodora, 14]

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Overall Site Method:

Based on the above equations and assumptions, for each of the 30 sites, the wind force and direction was calculated, to show the calculation process here below is Astoria site mentioned as example.

Table 12: Calculated wind force and direction at a specific site (Astoria).

By calculating the wind force and direction at the different locations, we can easily get the overall wind force, direction and torque, as shown in the following table.

Month Wind Speed Wind Direction F (N/m2) Fy (N/m2) Fx (N/m2)

Jan 4.4 90 0.07 0.00 -0.07

Feb 4.4 90 0.07 0.00 -0.07

Mar 4.3 113 0.07 0.03 -0.07

Apr 4.2 248 0.07 0.03 0.06

May 4.1 293 0.07 -0.03 0.06

Jun 4.2 315 0.07 -0.05 0.05

Jul 4.1 315 0.07 -0.05 0.05

Aug 3.9 315 0.06 -0.04 0.04

Sep 3.7 225 0.05 0.04 0.04

Oct 3.7 113 0.05 0.02 -0.05

Nov 4.3 113 0.07 0.03 -0.07

Dec 4.4 90 0.07 0.00 -0.07

Yearly mean 4.1 193 0.07 0.00 -0.01

Wind Direction 259.0 Wind Force 0.009

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Table 13: Overall wind force and direction based on site calculations.

Location Wind Force Wind Direction Fy= F*COS(Θ-180) Fx= F*SIN(Θ-180)

Astoria 0.009 259 0.00 0.01

Colima 0.024 254.7 0.01 0.02

Campbell River Airp. 0.002 109.5 0.00 0.00

Mclnnes Islands BC 0.063 237.2 0.03 0.05

Middleton Isl. Amos 0.15 259.5 0.03 0.15

Point Hope 0.059 265.3 0.00 0.06

San Felipe 0.073 142 0.06 -0.04

San Francisco CA 0.079 250.9 0.03 0.07

Stika Japonski 0.045 106.8 0.01 -0.04

Togiac Village 0.03 207.4 0.03 0.01

Barrow AK 0.128 253.1 0.04 0.12

Henrik Koreyerholme 0.131 177.9 0.13 0.00

Isachsen 0.008 254.2 0.00 0.01

Sachs Harbour 0.059 90 0.00 -0.06

Kap tobin 0.046 260.2 0.01 0.05

Prins Christian Sund 0.135 97.8 0.02 -0.13

Cartwright 0.081 103.9 0.02 -0.08

Port Aux Basques 0.071 269.9 0.00 0.07

Longue Pt De Mongue 0.014 258.5 0.00 0.01

Chatham Airp. NB 0.042 248.3 0.02 0.04

Western Head 0.047 126.5 0.03 -0.04

Portland ME 0.023 238.6 0.01 0.02

Storrs CT 0.045 250 0.02 0.04

Atlantic City 0.037 96.3 0.00 -0.04

Kinston 5se 0.026 223.1 0.02 0.02

Jacksonville Airp. 0.006 264.4 0.00 0.01

West Palm Beach 0.029 94.4 0.00 -0.03

Tampa FL 0.026 247.4 0.01 0.02

Houston Airp. 0.016 100.1 0.00 -0.02

0.018 0.010

Wind Force 0.021