SH: Calculation of the direction of maximum horizontal stress...

Description Usage Arguments Value Author(s) References Examples

View source: R/lund-sh.R

Description

Calculation of the direction of maximum horizontal stress using a 3D relative stress tensor

Usage

1
SH(R, n1, n2 = NULL, n3 = NULL)

Arguments

R

numeric; the principal stress ratio; defined as (S1 - S2)/(S1 - S3)

n1

numeric; the unit vector of the maximum principal stress, S1 (North,East,Up); if either n2 or n3 are NULL then this may be a three-column matrix

n2

numeric; unit vector of the intermediate principal stress, S2

n3

numeric; unit vector of the minimum principal stress, S3

Value

numeric; the azimuth of SHmax (c.w. from North) in radians with full or partial knowledge of the tectonic stress tensor, Geophys. J. Int., 170, 1328-1335, doi: 10.1111/j.1365-246X.2007.03468.x

Author(s)

Copyright (C) 1998-2007 Bjorn Lund

References

Equations 10 and 11 from Lund and Townend, (2007): Calculating horizontal stress orientations

Examples

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
# Dummy examples
Sf <- matrix(1:9, 3)
Sf[lower.tri(Sf)] = t(Sf)[lower.tri(Sf)]

S <- eigen(Sf)
principal_stresses <- S[['values']]
orientations <- S[['vectors']]

SH(0.5, orientations[,1], orientations[,2], orientations[,3])
SH(0.5, orientations)

Rseq <- seq(0, 1, length.out=21)
Azims <- sapply(Rseq, SH, n1=orientations)
plot(Rseq, Azims*180/pi, type='b')

abarbour/stress documentation built on Oct. 5, 2019, 11:20 a.m.