1. Structural geology Structure Reconstruction of regional stress
Ductile deformation
Fold
Foliation
Lineation
etc..
Brittle deformation
Joint
Tension gash
Styloite
Fault
etc..
Fault
Reconstruction of regional stress

2. Fault surfaces displaying the direction of slip lineation

3. Stereographic projection of a fault slip data set
Slickenside
lineation
pitch
pitch
Fault plane
Fault plane
Lower hemisphere project

4. obtaining the orientation of principal stress axes
Method of right dihedrons
obtaining the orientation
of principal stress axes
from statistic method

5. STEREOGRAPHIC NET
S’/S = f (inclination)
S’/S = const.

6. Wuff net
Schmidt net

7. Wuff net (equiangular) OPM isosceles triangle Schmidt net (equal-area)
ON/OP = tan (p/4-i/2)
ON = R tan (p/4-i/2)
Schmidt net (equal-area)
ON = OX, OX = (2)1/2 OH
OH/OP = sin (p/4-i/2)
ON = (2)1/2 R sin (p/4-i/2)

8. 3D inversion of field data in fault tectonics
Eigenvalues and eigenvectors of T give the orientation of principal stress axes (s1 , s2 and s3), as well as the shape ratio F of the stress ellipsoid (F = (s2-s3)/(s1-s3)).
(e.g., Angelier, 1979, 1984, 1989, 1990)

9. Inversion result Field measured data Computed stress axes
Theoretical fault shears
(Angelier, 1990)

10. (Chang C. P., Unpubl.)

11. the seismic focal mechanism
Example from
the seismic focal mechanism
F = (s2-s3)/(s1-s3)
case 1
0  F  1
case 1
case 2
 0
reverse and strike-slip
case 2
 1
normal and strike-slip
(Kao and Jian, 2001)