wiki:ShRot

Version 5 (modified by ramasuri, 10 years ago) (diff)

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rotate traces

command: ROT <trc-list> <azim> [<p1>[ <p2>[ <p3>]]]

Rotates traces in two or three dimensions, depending on the length of the <trc-list> parameter (two or three traces). The 2-dim rotation is described by the usual 2-dim rotation matrix (determinant +1).

          /  cos<azim>  -sin<azim>  \
   R  =   |                         | ,
          \  sin<azim>   cos<azim>  /

the 3-dim rotation is a rotation from the left-handed coordinate system (Z,N,E) to the right-handed system (L,Q,T) and has a determinant of -1

         /  cos<inci>  -cos<azim>*sin<inci>  -sin<azim>*sin<inci>  \
         |                                                         |
   R  =  |  sin<inci>   cos<azim>*cos<inci>   sin<azim>*cos<inci>  |
         |                                                         |
         \  0           sin<azim>            -cos<azim>            /

parameters

  • <trc-list> parameter type: trace list
    Specifies the traces to be rotated (length of list may be two or three).
  • <azim> parameter type: real
    Azimuth of rotation (in degrees).

If two traces specified:

  • <p1>, <p2> parameter type: real
    Time window of rotation. If no time window is passed the current display window is used.

If three traces specified:

  • <p1> parameter type: real
    Angle of incidence of rotation (in degrees).
  • <p2>, <p3> parameter type: real
    Time window of rotation. If no time window is passed the current display window is used.

quantifiers

in case of 3-component rotation you can use the following quantifiers to rotate between UVW (Galperin, e.g. STS-2) and ZNE orientation:

(comp. E. Wieland, Seismometry, in: International Handbook of Earthquake and Engineering Seismology, 2002.)

  • /uvw-zne
          /  1/SQRT(3)   1/SQRT(3)   1/SQRT(3)  \
     R =  |    0.0       1/SQRT(2)  -1/SQRT(2)  |
          \ -2/SQRT(6)   1/SQRT(6)   1/SQRT(6)  /
  • /zne-uvw
          /  1/SQRT(3)      0.0     -2/SQRT(6)  \
     R =  |  1/SQRT(3)   1/SQRT(2)   1/SQRT(6)  |
          \  1/SQRT(3)  -1/SQRT(2)   1/SQRT(6)  /

examples

rot 1,2 30.0
rotates the first two traces by an azimuth of 30 degrees
rot 1-3 30.0 10.0
rotates the first three traces by an azimuth of 30 degrees an an angle of incidence of 10 degrees