Geophysical Data Analysis 1

Course notes for Geophysical Data Analysis 1, taught by Dr. Ayunda Aulia Valencia, S.T., M.T. and Agus Riyanto, M.Si., at the Department of Geosciences, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, for the Bachelor's Program in Geophysics.

The course covers seismic data processing and analysis using Seismic Unix (SU), GNU Octave, and other computational tools. The repository contains lecture notes, practical exercises, scripts, and supporting figures organized by lecture week.

Seismic Processing Workflow

The following diagram illustrates a conventional seismic reflection processing workflow, from raw seismic data to migrated output. The actual processing sequence may vary depending on the dataset and processing objectives.

flowchart TD
    A[Reformat] --> B[Geometry and Trace Edits]
    B --> C[F-K Filter]
    C --> D[Bandpass Filter]
    D --> E[Elevation Statics Correction]
    E --> F[1st Pass Velocity Analysis]

    %% Velocity analysis and statics
    F --> F1[1st Pass Residual Statics]
    F1 --> F2[2nd Pass Velocity Analysis]
    F2 --> F3[2nd Pass Residual Statics]

    E --> G[Deconvolution]
    G --> H[Residual Statics]
    F3 --> H
    H --> I[Amplitude Recovery]
    F2 -.-> I
    I --> J[CDP Denoise]

    subgraph BRANCHES[" "]
        direction LR

        subgraph REL["Relative Amplitude"]
            direction TD
            R1[AGC] --> R1a[3rd Pass Velocity Analysis]
            R1 --> R2[NMO Re-apply: VEL-3]
            R1a --> R2
            R2 --> R3[Stack] --> R4[Time Migration] --> R5[SEG-Y Out VOL1]
        end

        subgraph TRUE["True Amplitude"]
            direction TD
            T1[NMO Re-apply: VEL-3]
            T2[Stack]
            T4[Time Migration]
            T5[SEG-Y Out VOL2]

            T1 --> T2 --> T4 --> T5
        end
    end

    J --> R1
    J --> T1
    R1a -.-> T1

    style BRANCHES fill:none,stroke:none
    style REL fill:#E8F1FC,stroke:#3973AC,stroke-width:2px,color:#17365D
    style TRUE fill:#E8F5E9,stroke:#438653,stroke-width:2px,color:#20552A

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Material

The repository is organized by lecture week. Each numbered directory contains the notes and related materials available for that topic.

Directory	Topic
01_linux-and-setup/	Introduction to Linux, WSL installation, and Seismic Unix setup
02_geometry/	Seismic geometry assignment and application using Octave and Python
03_gain/	Seismic amplitude recovery and gain testing
04_noise-attenuation/	Seismic noise attenuation
05_deconvolution-and-statics-correction/	Seismic deconvolution and statics correction, both elevation and residual statics
06_velocity-analysis-and-stacking/	Velocity analysis, normal moveout (NMO), and stacking
07_stolt-migration/	Stolt migration
09_octave-introduction/	Introduction to GNU Octave and MATLAB-compatible computing
10_seismic-attributes/	Seismic attributes
11_neural-network-in-seismic/	Neural networks in seismic applications
12_spectral-decomposition/	Seismic spectral decomposition
13_seismic-ray-tracing/	Seismic ray tracing
14_acoustic-finite-difference/	Acoustic wave simulation using the finite-difference method
15_velocity-well-tie-and-depth-conversion/	Velocity analysis, well-to-seismic tie, and depth conversion

Weeks 8 and 16 are reserved for the midterm and final examinations, respectively. Some materials may be incomplete or subject to revision as the course notes are updated.

Tools and Technologies

• Seismic Unix (SU): Seismic data processing and shell-based workflows.
• GNU Octave: Numerical computing, signal processing, and seismic analysis. MATLAB-compatible scripts may also be used where applicable.
• Python: Supporting scripts and computational exercises.
• Linux/Unix: Command-line tools and scripting for seismic processing.

Refer to the individual lecture notes for topic-specific instructions, scripts, and requirements.

Contributing

Corrections, improvements, and additional examples are welcome.

1. Fork the repository.
2. Create a branch for your changes.
3. Commit your changes with descriptive commit messages.
4. Push your branch and submit a pull request.

License

No license has currently been specified for this repository. Unless otherwise stated, all rights are reserved by the repository owner.

Acknowledgments

• Dr. Ayunda Aulia Valencia, S.T., M.T., and Agus Riyanto, M.Si., for teaching Geophysical Data Analysis 1 (SCGF603501).
• The Center for Wave Phenomena (CWP) at the Colorado School of Mines for developing Seismic Unix.