1. Final Review – session 2 Environmental and Exploration Geophysics I
tom.h.wilson
Department of Geology and Geography
West Virginia University
Morgantown, WV
Tom Wilson, Department of Geology and Geography

2. On tap for the day Continued exam review
Brief answers to review problems from last time with some additional group problems to consider today
All group and review problems are linked on the class page.
Extra credit magnetics lab? Turn in today before leaving.
Final is from 3-5pm on Tuesday, December 15th – rm 325 Brooks
Tom Wilson, Department of Geology and Geography

3. 3-5pm Tuesday, December 15th 325 Brooks Hall
Spread out in the exam room. Sit in back of the person in front of you.
Bring a pencil, ruler, eraser and calculator Show your work!
I will hand out an equation list following the earlier format
See
See links in sessions 29 and 30, class web page for review materials
I’m generally in my office. If you have questions drop by – but me to ensure I’ll be around.
Tom Wilson, Department of Geology and Geography

4. Exam Schedule: http://registrar. wvu
REMEMBER! Exam will be held in rm 325 Brooks Hall
No early or make-up exams offered!
Tom Wilson, Department of Geology and Geography

5. Recall grade breakdown – regular section
32% homework
5% papers
28% lab reports
5% attendance/participation
10% mid term
The grade summaries posted last time covered about 80% of your semester grade.
Final exam counts 20% of your total semester grade
STUDY HARD!
Tom Wilson, Department of Geology and Geography

6. Recall grade breakdown – writing section
Regular section:
32% homework
5% papers
28% lab reports
5% attendance/participation
5% mid term
10% Essays
At this point, we have about 85% of the grades factored in.
Final exam counts 15% of your total semester grade
STUDY HARD!
Tom Wilson, Department of Geology and Geography

7. Brief answers to the general review questions from last time
Problem 1: The butte – a)44.5mG, b) infinite plate, c) 31mG; d) 13.46mG.
Problem 2: use Pythagorean theorem to solve for ZE in terms of FE and HE
Problem 3: i=67.44o,XE=20,019nT, YE=-3350nT, ZE=48,856nT
Problem 4: 1.9nT
Problem 5: The theoretical gravity is an estimate of the acceleration at a point on the Earth’s surface that incorporates known “non-geological” contributions to acceleration.
Problem 6: gt = g - gFA + gBP - gT + ….
Tom Wilson, Department of Geology and Geography

8. Answers to group problems from last time
Problem 1: (Devil’s tower) -0.3mG decrease in your observation
Problem 2: Vertical cylinder with depth to top of 9.85m
Problem 3: Horizontal cylinder, depth 484m
Tom Wilson, Department of Geology and Geography

9. Problem 2 (see class link lecture 29 group review)
Tom Wilson, Department of Geology and Geography

10. Problem 3 from last class’ Group Review problems
Tom Wilson, Department of Geology and Geography

11. Brief answers to general review problems in today’s handout …
Chapter 7 problems:
See graded homework
Answers to review problems just handed out …
Problem 1: 6,371,953m
Problem 2: 4.3nT
Problem 3 & 4: estimate of g that does not incorporate subsurface geological complexity and includes gT&D.
Tom Wilson, Department of Geology and Geography

12. Brief answers to general review problems in today’s handout … (cont.)
Problem 5: gtcbg=gt - g + gFA - gBP + gT ± gT&D.
Problem 6: a) sphere, b) 0.02mG c) 7.7m, d) 196
Problem 7: km
Problem 8: V cyl, 4m
Problem 9: k=0.095 emu
Problem 10: mG
Tom Wilson, Department of Geology and Geography

13. Some additional group problems for exam review …
Start working over these in groups.
We’ll take some time to review questions before leaving …
Take about 10 minutes or so to set up and work through some of these problems
Tom Wilson, Department of Geology and Geography

14. Tom Wilson, Department of Geology and Geography
Today’s group problem 1 – (handed out last time. Did you try to work through them?)
Tom Wilson, Department of Geology and Geography

15. Tom Wilson, Department of Geology and Geography
This problem requires measuring diagnostic positions or distance and depth estimates
How would you label the table?
Tom Wilson, Department of Geology and Geography

16. Tables will be provided in the equation list
In this group problem you will find this is a vertical cylinder with approximated depth to top of about 20m
Tom Wilson, Department of Geology and Geography

17. Tom Wilson, Department of Geology and Geography
Today’s group problem 2
Tom Wilson, Department of Geology and Geography

18. Tom Wilson, Department of Geology and Geography
Another problem that requires analysis of depths obtained from two different assumed geometries
Tom Wilson, Department of Geology and Geography

19. Remember this is a gravity problem
So you’ll get your depth index multipliers from the gravity tables.
Tom Wilson, Department of Geology and Geography

20. Tom Wilson, Department of Geology and Geography
Group 2 problem
The table below shows the setup you’d use to answer problem 2. Note that you should get horizontal cylinder at a depth of ~7 m.
Position is the distance from the anomaly peak to the point where the anomaly falls to ½, ¼ etc of it’s maximum (or minimum value). DIM is depth index multiplier
Tom Wilson, Department of Geology and Geography

21. Tom Wilson, Department of Geology and Geography
Today’s group problem 3
Remember tide and drift correction is
Tom Wilson, Department of Geology and Geography

22. Tom Wilson, Department of Geology and Geography
You should find that
Graphically obvious the value is about 1mG less
So, base 6 has a value of 3 mG relative to the main base or main reference value of 0 for this survey.
Tom Wilson, Department of Geology and Geography

23. Again - Exam Schedule: http://registrar. wvu
I’ll be around between now and next Tuesday but drop me an if you have a specific time in mind.
REMEMBER! Exam will be held in rm 325 Brooks Hall
No early or make-up exams offered!
Tom Wilson, Department of Geology and Geography