هسته زمین: دینامیک، ساختار، چرخش

Published by the American Geophysical Union as part of the __Geodynamics Series__. Geomagnetism, dynamo theory, seismology, geodesy, and mineral physics each present significant perspectives on Earth's core. When interelated, scientists gain and invaluable vantage from which to understans the evolution, dynamics, and state of the core. __Earth's Core: Dynamics, Structure, Rotation__ presents a synthesis of current understanding in proactive analyses of Earth core phenomena, including research in core composition, wave-speed variation, magnetic field signatures, core mantle boundary issues, and more. Content: Title Page......Page 3 Copyright......Page 4 Contents......Page 5 Preface......Page 7 Stephen Zatman Dedication......Page 8 Introduction......Page 9 1. Introduction......Page 12 2. Spectra, Receiver Strips and Splitting Functions ......Page 14 3. Looking for a Time-Dependent Signal ......Page 17 4. Splitting Functions for Real Data ......Page 19 5. Determining the Final Rotation Rates ......Page 22 6. Does the Rotation Rate Depend on the Mantle Correction? ......Page 24 7. Discussion......Page 25 References......Page 27 Study of Inner Core Structure and Rotation Using Seismic Records from Novaya Zemlya Underground Nuclear Tests ......Page 29 On the Origin of Complexity in PKP Travel Time Data. ......Page 37 1. Introduction......Page 38 2. Description of the Datasets and Some Specific Trends ......Page 39 3. Complex Inner Core Anisotropy or Strong Heterogeneity at the Base of the Mantle? ......Page 41 4. Different Global Projections of the PKP Travel Time Residuals ......Page 43 5. Possible Alternative Models to the Hemispherical Inner Core Anisotropy ......Page 46 6. Conclusions......Page 47 References......Page 49 Three-Dimensional Structure and Differential Rotation of the Inner Core ......Page 51 2. 3-D Structure of the Inner Core ......Page 52 3. Observations of Inner-Core Rotation ......Page 60 4. Potential Biases in Determination of Inner-Core Rotation ......Page 64 5. Discussion and Conclusion ......Page 66 References......Page 67 Inner Core Rotation: A Critical Appraisal......Page 70 Introduction......Page 71 The Structure of the Inner Core and the Departure from Cylindrical Symmetry ......Page 72 Inner Core Rotation: Investigations at the Worldwide Scale ......Page 76 Inner Core Rotation: Evidence Fromresidual Variations Along Particular Paths ......Page 78 Discussion and Conclusion ......Page 83 References......Page 85 1. Introduction......Page 88 2. Birch's Phase Diagram of Iron in the T-V Plane ......Page 89 3. The Three Established Triple Points ......Page 90 4. The Values of ̿V at Phase Boundaries and Triple Points......Page 92 5. The є Iron Solidus Melting Curve......Page 94 6. Relationship Between γeff and Electronic Specific Heat ......Page 97 7. Evaluation of the Integration Constant and Thermal Pressure for Tmp ......Page 98 8. The Assembled Phase Diagram......Page 99 9. Implications for the Earth's Core ......Page 100 10. Considerations Concerning Two Additional Solid Phases Added to the Five Well-Established Phase ......Page 105 References......Page 106 Solidification of the Earth's Core ......Page 109 1. Introduction......Page 110 2. Review of Alloy Phase Diagrams ......Page 111 3. Composition and Phase Diagram of the Core ......Page 112 4. Review of Directional Solidification and Crystal Growth of Metallic Alloys ......Page 115 5. Crystal Growth in the Core ......Page 117 7. Compositional Convection in the Outercore Driven by Solidification ......Page 123 References......Page 127 Introduction......Page 132 Discussion and Application ......Page 135 References......Page 138 1. Introduction......Page 140 2. Geophysical Background......Page 141 3. Mineral Physics Methods......Page 145 4. Physical Properties of Dense Iron ......Page 149 5. Properties of the Inner Core ......Page 155 6. Conclusions and Outlook ......Page 158 References......Page 159 Introduction......Page 165 Theory......Page 166 Observation......Page 172 Conclusions......Page 178 References......Page 179 1. Introduction......Page 182 2. Observational Background......Page 183 4. Viscous and Thermal Diffusive Timescales ......Page 184 5. Additional Timescales......Page 185 6. The Smallness of Ro and E ......Page 187 7. Stiff Systems......Page 189 9. Conclusion......Page 191 References......Page 192 1. Introduction......Page 194 2. Core Dynamics and Geodynamo Modeling ......Page 196 4. Gravitational Coupling......Page 200 5. Electromagnetic Coupling......Page 202 6. Topographic Coupling......Page 205 7. Conclusion......Page 207 Appendix A: Angular Momentum Variation of the Core ......Page 209 Appendix B: Partial Slippery Boundary Conditions......Page 210 References......Page 212 1. Introduction......Page 214 2. Radial Core Structure and its Evolution ......Page 215 3. Lateral Variation of Core Structures ......Page 221 4. Future Prospects......Page 227 Appendix: Derivation of Eq.20 ......Page 228 References......Page 229 1. Introduction......Page 233 2. Decadal Flows in the Tangent Cylinder ......Page 235 3. Implications for Inner Core Coupling ......Page 236 4. Conclusions......Page 238 References......Page 239 Introduction......Page 241 Density Profile in the Outer Core ......Page 242 Choice of Spheroidal Modes for this Study ......Page 243 Seismic Results for Modified Models ......Page 245 Wobble Periods for Modified Models ......Page 247 Conclusions......Page 248 References......Page 249 1. Introduction......Page 251 2. Geomagnetism and Flow Modeling ......Page 252 3. Core Angular Momentum......Page 254 4. Core-Mantle Coupling Mechanisms ......Page 255 References......Page 258 Introduction......Page 262 Nutation Model......Page 264 Nutations and Topography at the Core Mantle Boundary and at the Inner Core Boundary ......Page 266 Constraint to the Poincare Motion ......Page 267 Electromagnetic Coupling in Mhb2000 ......Page 268 Inner Core Viscosity Effects......Page 271 Inner Core Viscosity and Electromagnetic Coupling;results and Discussion ......Page 272 Conclusions......Page 274 References......Page 275 Title Page 3 Copyright 4 Contents 5 Preface 7 Stephen Zatman Dedication 8 Introduction 9 The Earth's Free Oscillations and the Differential Rotation of the Inner Core 12 1. Introduction 12 2. Spectra, Receiver Strips and Splitting Functions 14 3. Looking for a Time-Dependent Signal 17 4. Splitting Functions for Real Data 19 5. Determining the Final Rotation Rates 22 6. Does the Rotation Rate Depend on the Mantle Correction? 24 7. Discussion 25 References 27 Study of Inner Core Structure and Rotation Using Seismic Records from Novaya Zemlya Underground Nuclear Tests 29 On the Origin of Complexity in PKP Travel Time Data. 37 1. Introduction 38 2. Description of the Datasets and Some Specific Trends 39 3. Complex Inner Core Anisotropy or Strong Heterogeneity at the Base of the Mantle? 41 4. Different Global Projections of the PKP Travel Time Residuals 43 5. Possible Alternative Models to the Hemispherical Inner Core Anisotropy 46 6. Conclusions 47 References 49 Three-Dimensional Structure and Differential Rotation of the Inner Core 51 1. Introduction 52 2. 3-D Structure of the Inner Core 52 3. Observations of Inner-Core Rotation 60 4. Potential Biases in Determination of Inner-Core Rotation 64 5. Discussion and Conclusion 66 References 67 Inner Core Rotation: A Critical Appraisal 70 Introduction 71 The Structure of the Inner Core and the Departure from Cylindrical Symmetry 72 Inner Core Rotation: Investigations at the Worldwide Scale 76 Inner Core Rotation: Evidence Fromresidual Variations Along Particular Paths 78 Discussion and Conclusion 83 References 85 The Three-Dimensional Phase Diagram of Iron 88 1. Introduction 88 2. Birch's Phase Diagram of Iron in the T-V Plane 89 3. The Three Established Triple Points 90 4. The Values of ̿V at Phase Boundaries and Triple Points 92 5. The є Iron Solidus Melting Curve 94 6. Relationship Between γeff and Electronic Specific Heat 97 7. Evaluation of the Integration Constant and Thermal Pressure for Tmp 98 8. The Assembled Phase Diagram 99 9. Implications for the Earth's Core 100 10. Considerations Concerning Two Additional Solid Phases Added to the Five Well-Established Phase 105 References 106 Solidification of the Earth's Core 109 1. Introduction 110 2. Review of Alloy Phase Diagrams 111 3. Composition and Phase Diagram of the Core 112 4. Review of Directional Solidification and Crystal Growth of Metallic Alloys 115 5. Crystal Growth in the Core 117 7. Compositional Convection in the Outercore Driven by Solidification 123 8. Conclusions 127 References 127 Thermodynamics of Epsilon Iron at Core Physical Conditions 132 Introduction 132 Discussion and Application 135 References 138 Physical Properties of Iron in the Inner Core 140 1. Introduction 140 2. Geophysical Background 141 3. Mineral Physics Methods 145 4. Physical Properties of Dense Iron 149 5. Properties of the Inner Core 155 6. Conclusions and Outlook 158 References 159 Thermal Core-Mantle Interactions: Theory and Observations 165 Introduction 165 Theory 166 Observation 172 Conclusions 178 References 179 The Range of Timescales on which the Geodynamo Operates 182 1. Introduction 182 2. Observational Background 183 3. Basic Timescales and Equations 184 4. Viscous and Thermal Diffusive Timescales 184 5. Additional Timescales 185 6. The Smallness of Ro and E 187 7. Stiff Systems 189 8. Implications 191 9. Conclusion 191 References 192 Geodynamo Modeling and Core-Mantle Interactions 194 1. Introduction 194 2. Core Dynamics and Geodynamo Modeling 196 3. Viscous Coupling 200 4. Gravitational Coupling 200 5. Electromagnetic Coupling 202 6. Topographic Coupling 205 7. Conclusion 207 Appendix A: Angular Momentum Variation of the Core 209 Appendix B: Partial Slippery Boundary Conditions 210 References 212 Thermal Interactions Between the Mantle, Outer and Inner Cores, and the Resulting Structural Evolution of the Core 214 1. Introduction 214 2. Radial Core Structure and its Evolution 215 3. Lateral Variation of Core Structures 221 4. Future Prospects 227 Appendix: Derivation of Eq.20 228 References 229 Decadal Oscillations of the Earth's Core, Angular Momentum Exchange, and Inner Core Rotation 233 1. Introduction 233 2. Decadal Flows in the Tangent Cylinder 235 3. Implications for Inner Core Coupling 236 4. Conclusions 238 References 239 Can a Stably Stratified Layer in the Core be Detected Using Seismic Normal Modes or Earth Rotation? 241 Introduction 241 Density Profile in the Outer Core 242 Choice of Spheroidal Modes for this Study 243 Seismic Results for Modified Models 245 Wobble Periods for Modified Models 247 Conclusions 248 References 249 The Core and Fluctuations in the Earth's Rotation 251 1. Introduction 251 2. Geomagnetism and Flow Modeling 252 3. Core Angular Momentum 254 4. Core-Mantle Coupling Mechanisms 255 5. Conclusion 258 References 258 Information About the Core from Earth Nutation 262 Introduction 262 Nutation Model 264 Nutations and Topography at the Core Mantle Boundary and at the Inner Core Boundary 266 Constraint to the Poincare Motion 267 Electromagnetic Coupling in Mhb2000 268 Inner Core Viscosity Effects 271 Inner Core Viscosity and Electromagnetic Coupling;results and Discussion 272 Conclusions 274 References 275 This volume contains seventeen papers that are a mixture of presented papers from the Geophysical Union session on Core Dynamics, held in the Fall of 2000 in San Francisco, and invited papers for this volume. An international group of contributors present their research on topics grouped under the broad themes of seismology, mineral physics, geomagnetics and geodynamics, and geodosy. Individual topics include the Earth's free oscillations and the differential rotation of the inner core, complexity in PKP travel time data, thermal core-mantle interactions, and the core and fluctuations in the Earth's rotation. (Annotation copyrighted by Book News, Inc., Portland, OR.) This volume contains 17 papers that are a mixture of presented papers from the Geophysical Union session on Core Dynamics, held in the Fall of 2000 in San Francisco, and invited papers for this volume. An international group of contributors present their research on topics grouped under the broad themes of seismology, mineral physics, geomagnetics and geodynamics, and geodosy. Individual topics include the Earth's free oscillations and the differential rotation of the inner core, complexity in PKP travel time data, thermal core-mantle interactions, and the core and fluctuations in the Earth's rotation. Annotation copyrighted by Book News, Inc., Portland, OR Geomagnetism, dynamo theory, seismology, geodesy, and mineral physics each present significant perspectives on Earth's core. When interelated, scientists gain and invaluable vantage from which to understans the evolution, dynamics, and state of the core. Earth's Core: Dynamics, Structure, Rotation presents a synthesis of current understanding in proactive analyses of Earth core phenomena, including research in core composition, wave-speed variation, magnetic field signatures, core mantle boundary issues, and more.