Geophysical Exploration of Crustal Structure

(MC, 2024 Fall semester)

Japanese | English


[Schedule] [Note] [Exercise] [Submission of reports and homeworks] [References]

What's New


Scopes

Geophysical exploration is a promising tool to obtain information from the subsurface to understand crustal structures, properties, and activities by measuring physical response from the Earth. It is natural to say that understanding the inner Earth starts from looking inside the Earth. In presentations at earth sciences conferences, you will see seismic reflection and resistivity sections. Even geologists should know what these sections represent. Geophysicists, like you, can not leave them as a black box even if you do not have special interests in data processing.

This course deals with Exploration Geophysics. Due to the limited time, the lecture mainly focuses on basic theory and concepts. Applications and real implementations will be set aside. A computer exercise on data processing is included to help understand lectures.

Knowledge of applied mathematics and physics, which includes elasticity, wave theory and electromagnetics, is preferable. They will help you understand the course easily. These basic subjects are common in seismology, geodeasy, and so on.

This course aims to learn the attitude toward extracting target information from the observed data and to understand the importance of basic mathematics and physics.


Schedule

The schedule will be updated occasionally.

No. Date Contents Explanation
1
Oct. 02 Basics of geophysical exploration
2
Oct. 09 Basics of elastic wave theory
3
Oct. 16 Basics of elastic wave theory (cont'd)
4
Oct. 23 Basics of seismic reflection method
  • Basic ideas, data acquisition, processing flow
  • Convolution model of wave propagation in subsurface
  • Handout (Reflection seismic basics)
  • Exercise 1
5
Oct. 30 Seismic data analysis (Filters)
  • Digital filters
  • Frequency (bandpass) filters
  • Velocity (f-k) filters
  • Handout (Data analysis : Filter)
  • Handout (Figures from Chapter 1 of Yilmaz's Book)
  • Exercise 2
6
Nov. 13 Seismic data analysis (Filters, cont'd)
  • Wiener filter
  • Deconvolution
  • Handout (Appendix B of Yilmaz's Book)
  • Handout (supplement for Laplace transform and z-transform)
  • Exercise 3
7
Nov. 20 Seismic data analysis (processing)
  • Velocity analysis
  • Nomal moveout (NMO) correction
  • Common-midpoint (CMP) stacking
  • Handout (Data processing : NMO, Velocity analysis, CMP)
  • Exercise 4
8
Nov. 27 Seismic data analysis (Migration)
  • Basics of seismic migration
  • Wave equation migration
  • Handout (Migration)
  • Handout (Appendix D of Yilmaz's Book)
  • Exercise 5
-
Dec. 04
---
Class is called off due to the SEGJ Fall meeting.
*
Dec. 04
Data processing excercise (1)
  • Data processing of real 2D seismic data using Seismic Un*x
  • Contents: Data manupilation, display, filter, gain.
  • Excercise 6
  • Students are encouraged to proceed to the exercise in advance. The time required is about 0.5 hour.

  • You may continue with Exercise 7 when finished.
9
Dec. 11 Interpretation of seismic section
  • Interpretation of seismic section
  • Acousatic impedance analysis
  • Brightspot, AVO
  • 3-D seismic method
  • Handout (Interpretation)
  • Handout (interpretation exercise)
10
Dec. 18
Data processing excercise (2)
  • Data processing of real 2D seismic data using Seismic Un*x
  • Contents: Vvelocity analysis, CMP stacking, migration, depth conversion.
  • Excercise 7
  • Students feel free to proceed to the exercise in advance. The time required is about 1.5 hour.
  • The lecturer is present in the room and provide assistance during the class.

  • Visit here for your final products (report).
  • Deadline: Jan 17, 2024.
11
Dec. 25 Basics of electromagnetic theory
  • Maxwell's equation
  • Propagation of electromagnetic wave
  • Handout (Basics of electromagnetic theory and MT method)
  • Today's homework
12
Jan. 15 Electromagnetic method (Magnetotelluric method)
  • Basics of Magnetotelluric method
  • Derivation of MT parameters
  • Inversion
  • Handout (Basics of electromagnetic theory and MT method)
  • Today's homework
13
Jan. 22 Application of geophysical exploration
  • Application of MT method to earth science
  • Application of seismic reflection method to earth science
  • Discussion on th excercise results.
  • Handout (Application of seismic method)
  • Handout (Application of MT method)
14
Jan. 29 Topics on geophysical exploration
  • Topics are on request.
  • Past topics (example)
    • Exploration Geophysics for Civil Engineering
    • Inversions and full waveform inversion (FWI)
    • Electrical survey, gravity survey and magnetic survey
    • Seismic intererometry
  • Final report


Note


Exercise

Exercise on data processing of seismic reflection method. Updated occasionally.


Submission of reports and homeworks


References


Last modified: Tue Oct 1 15:08:04 JST 2024