1. Attitudes of Planes and Lines

2. Frame of Reference
Always need to be thinking in 3 dimensions

3. The Brunton Compass ~$250 to replace
you are responsible for your compass!

4. The Brunton Compass

5. Azimuth and Quadrant on Map
315°
045°
N45°W
N45°E
S45°W
S45°E
225°
135°
Azimuth – measured in 0 to 360 degrees from true north in clockwise
Quadrant – measured in 90 degree increments either from N or S to E or W

6. Azimuth and Quadrant on Compass
East and West are reversed!
In azimuth ring, 0 to 360 degrees are marked from true north counterclockwise

7. Earth’s Magnetic Field
physically
North Pole
South Pole
By definition, North Magnetic Pole is the wandering point on the Earth’s surface
where the Earth’s magnetic field points vertically downwards. So it is still near
the geographic north pole.

8. Magnetic Declination declination = 15˚
your compass needs to be adjusted for the magnetic declination in the area in which you are using it
declination = 15˚

9. Adjustment to Compass 0 Declination 15 East Declination
15 West Declination

10. Planes and Lines Planar Features:
Bedding, fractures, fault planes, dikes
Linear Features:
Grooves and streaks on a surface, intersections of two planar features, fold hinge lines

11. Linear Features
lineations

12. Attitudes of Planes and Lines
described by strike and dip
Lines:
described by trend and plunge

13. Strike Strike Line A horizontal line in the plane Strike
the angle between the strike line and true north
Measured in azimuth or quadrant

14. Dip Dip Line: A line in the plane perpendicular to the strike line
Dip (Dip angle):
the angle from a horizontal down to the dip line in a vertical plane
Measured from 0–90 degrees
Dip Direction:
Always need to be specified as downdip

15. occurs when the dip of a plane is measured oblique to strike
Apparent Dip
occurs when the dip of a plane is measured oblique to strike

16. Measuring Planes
when your compass is leveled horizontally along an inclined plane, it measures the strike of that plane

17. Measuring Planes Cont…

18. Right Hand Rule

19. Sighting

20. Recording Strike and Dip
strike is recorded first, then dip
S85ºE, 23ºSW
095º, 23ºSW
strike
dip angle
dip direction

21. Trend (Bearing) Trend Line
A line orthogonally projected onto a horizontal plane
Trend
the angle between the trend line and true north
Measured in azimuth or quadrant

22. Plunge
plunge:
the angle that a line makes with respect to a horizontal plane as measured in a vertical plane
measured from 0 – 90 degrees

23. Rake or Pitch
the angle between a lineation and the horizontal line measured in the plane where the line occurs

24. Measuring Lines
trend
plunge

25. Recording Linear Features
Plunge is recorded first, then trend
35º, S66ºW
35º, 246º
plunge
trend