Calculates the direction of maximum horizontal stress using only the
directions of the principal stress and \(R = \frac{S1 - S2}{S1 - S3}\).
This function Equations 11 and 10 from Lund and Townend (2007).
Arguments
- S1, S2, S3
numeric three column vectors. The principal stress orientations.
The variables hold the coordinates in the North, East and Down geographical
coordinate system, e.g. S1 = c(s1N,s1E,s1D)
- R
numeric. Relative magnitude of S2 with respect to S1 and S3:
\(R = \frac{S1 - S2}{S1 - S3}\)
Value
The direction of SH from North, angle in degrees
References
Lund and Townend, (2007). Calculating horizontal stress
orientations with full or partial knowledge of the tectonic stress tensor,
Geophys. J. Int., doi:doi:10.1111/j.1365-246X.2007.03468.x
.
Examples
S1 <- Line(250.89, 70.07)
S3 <- Line(103.01, 17.07)
S2 <- vcross(S3, S1)
SH(S1, S2, S3, R = 1)
#> [1] 70.89