grotseis {RSEIS}R Documentation

Get seismic rotation matrix

Description

Set up a rotation matrix for a seismic trace. Rotation matrix is 3D, although this rotation only creates a rotation for conversion to radial-transverse orientation.

Usage

grotseis(ang, flip = FALSE)

Arguments

ang Angle to rotate horizontal components, degrees
flip Logical, TRUE=flip the vertical axis, default=FALSE

Details

Returns a 3 by 3 matrix used for rotationg a 3-component seismic record, usually stored as an N by 3 matrix. Only the N-E components are rotated, North component is assumed to be in position 2 and the east compnent is assumed to be in position 3. The vertical component can be flipped.

Value

3 by 3 rotation matrix.

Note

Positive radial is away from the source (direction of wave propagation). Positive transverse is to the right when facing the direction of wave propagation.

Author(s)

Jonathan M. Lees<jonathan.lees@unc.edu>

See Also

distaz

Examples

STAXY=list()

STAXY$'x'=c(-2.9162198461534,-2.49599248511068,-2.85909405321704,-1.96135073099434,
-6.50413342506259,2.64026676599765,
-3.95701139503518,-2.84082134537436,-0.0457817300378462,-2.74214190991955)
STAXY$'y'=c(-7.83435541676815,-4.46180337254565,-6.46036190991833,-5.01212763828746,
-2.56091416028758,
5.31173503708142,2.10545324503380,-0.87490923667824,-0.172422188354707,-1.52055218789877)

STAXY$'lat'=c(14.685621984127,14.7159182222222,14.6979647030651,14.710975070028,
14.7329873333333,14.8037143111518
,14.7749104943935,14.7481391460905,14.7544511215933,14.7423394025875)

STAXY$'lon'=c(268.420918730159,268.424817925926,268.421447725096,268.429783940243,268.387586722222,
268.472531954619,268.41123843527,268.421611351166,268.447574716981,268.422528671994)

STAXY$'z'=c(0.92522857142857,1.48225333333333,1.14740517241379,1.4423781512605,1.51148,
2.53268681318681,2.70014678899083,2.04094444444444,2.90827547169811,2.31817123287671)

STAXY$'cen'=c(14.756,-91.552)

STAXY$name=c('OBS','CAR','MAR','CAS','MTB','STA','STE','MOT','SUM','DOM')
sguitoXY=list()
sguitoXY$'x'=c(-1.78551922571555)
sguitoXY$'y'=c(-1.80850340813817)
sguitoXY$'lat'=c(14.7397535236)
sguitoXY$'lon'=c(268.4314147874)
sguitoXY$'z'=c(2.501)

DAZ = distaz(STAXY$lat, STAXY$lon, sguitoXY$lat, sguitoXY$lon)

STAXY$az = DAZ$baz

plot(STAXY$x, STAXY$y, asp=1, xaxs="r"  , yaxs="r" )

text(STAXY$x, STAXY$y,STAXY$name, pos=3)

points(0,0, pch=3)
points(sguitoXY$x,sguitoXY$y , pch=8)

segments(sguitoXY$x, sguitoXY$y, STAXY$x, STAXY$y, col="green", lty=2)

vecs  = rbind(c(0,0,1), c(0,1,0))

for( i in 1:length(STAXY$x))
  {
rbaz = grotseis(STAXY$az[i], flip=FALSE)
bvec  = vecs 
##############   red is north, blue east
########  red is radial positive away from source, blue is transverse
##########   blue is positive to the right, if facing away from source
## arrows(STAXY$x[i],STAXY$y[i], STAXY$x[i]+vecs[,2], STAXY$y[i]+vecs[,3], col=c("red", "blue"), lty=2)
arrows(STAXY$x[i],STAXY$y[i], STAXY$x[i]+bvec[,2], STAXY$y[i]+bvec[,3], col=c("red", "blue"))

}





[Package RSEIS version 2.1-4 Index]