rotate2D | R Documentation |
The rotate2D() function rotates the two horizontal components of a
seismic signal into Radial and Transverse components returned as a list of 2 Stream
objects.
rotate2D(st1, st2, angle)
st1 |
horizontal |
st2 |
horizontal |
angle |
angle (degrees) of the rotation |
The rotation
web service returns Radial and Transverse seismic Streams, generated by
rotating st1
and st2
by angle
degrees.
The rotation service uses the following transformation matrix to change the output vectors for 2-D horizontal transformations
M_{2D} = ≤ft[ \begin{array}{cc} cos α & sin α \cr -sin α & cos α \end{array} \right]
≤ft[ \begin{array}{c} R \cr T \end{array} \right] = M_{2D} ≤ft[ \begin{array}{c} N \cr E \end{array} \right]
where :
N and E represent data from the original (horizontal) orientations. R and T represent the Radial and Transverse components. \eqn{\alpha} is the azimuth angle measured clockwise from north.
A list of two Stream
objects stR
and stT
is returned.
N and E are determined by the Stream
@stats@azimuth values. If Stream
@stats@azimuth values are not defined,
st1 is assumed to be N and st2 is assumed to be E. Orthogonality is also assumed to be correct.
Jonathan Callahan jonathan@mazamascience.com
IRIS DMC rotation web service:
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