Seismic Study of the Crust and Mantle Lithosphere in Cameroo

发布时间：2025-03-20 00:37

　　One of the main goals of seismology is to use seismic waves emanating from active and passive sources to make inferences about the properties and structure of the Earth and substantial successes have been recorded in recent decades.Some of these can be attributed to the rapid advancement in computing technology and the ever increasing deployment of dense seismic networks at different locations on the earth.The latter has led to the availability of quality seismic data and allowed a great variety ...

【文章页数】：154 页

【学位级别】：博士

【文章目录】：
Acknowledgement
Abstract
1. Introduction
    1.1 Geological Background of Cameroon
    1.2 Motivation and Thesis Objectives
    1.3 The Cameroon Broadband Seismic Experiment
    1.4 Previous Studies Using CBSE Array Data
    1.5 Achievements and Thesis Outline
2. Methodology
    2.1 Seismic Waves
    2.2 The Ambient Seismic Noise Field
    2.3 Ambient Noise Cross-Correlation Method
    2.4 Computation of Surface-wave Dispersion
    2.5 Surface Wave Tomography
    2.6 Rayleigh Wave Ellipticity
    2.7 Receiver Function Method
    2.8 Joint Seismic Inversions
3. Crustal Radial Anisotropy beneath Cameroon from Ambient Noise Tomography
    3.1 Introduction
    3.2 Data and Methodology
    3.3 Results and Discussion
        3.3.1 Cross-Correlation
        3.3.2 Phase Velocity Measurement and Tomography
        3.3.3 3-D Shear Wave Velocity Models
        3.3.4 Cross Sections
        3.3.5 Uncertainty in Radial Anisotropy
    3.4 Conclusions
4. Crust-Mantle Coupling Mechanism in Cameroon, West Africa, Revealed By 3D S-Wave Velocity and Azimuthal Anisotropy
    4.1 Introduction
    4.2 Data and Methodology
        4.2.1 Data
        4.2.2 Data Processing
        4.2.3 Dispersion Analysis
        4.2.4 Phase Velocity Maps and Azimuthal Anisotropy
        4.2.5 Depth Inversion for Shear Wave Speed and Azimuthal Anisotropy
    4.3 Results and Discussion
        4.3.1 Discrepancy between the Phase Velocity Measurements from ANT andTS Method
        4.3.2 Checkerboard Tests
        4.3.3 2D Isotropic and Anisotropic Phase Velocity Maps
        4.3.4 3D Models of Isotropic and Azimuthal Anisotropy
        4.3.5 Cross Sections along the NA Inverted 3D Isotropic Vsv Model
        4.3.6 Correlation with Previous SKS Splitting Studies
    4.4 Conclusions
5. Further Constraints on the Shear Wave Velocity Structure of Cameroon from JointInversion of Receiver Function, Rayleigh Wave Dispersion and EllipticityMeasurements
    5.1 Introduction
    5.2 Data and Methodology
        5.2.1 Rayleigh Wave Dispersion Data
        5.2.2 P-Wave Receiver Functions
        5.2.3 Rayleigh Wave Ellipticity (ZH Ratio)
        5.2.4 Joint Inversion Scheme
    5.3 Results and Discussion
        5.3.1 Rayleigh Wave Ellipticity Measurements (ZH Ratio)
        5.3.2 Inverted 1-D Velocity Models
        5.3.3 Localized High Velocity Layer (HVL) In the Uppermost Crust
        5.3.4 Crustal Thickness Estimate
        5.3.5 V_p/V_s Ratio (Poisson's Ratio)
    5.4 Conclusions
6. Conclusions and Future Directions
    6.1 Summary of Findings
    6.2 Viable Geodynamic Model for the CVL
    6.3 Further Work
References
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