Rotation of seismic data into Radial/Tangential directions

[dlnorgaard]

VDAP Geophysics team would like ability to rotate seismic data within Swarm into Radial/Tangential directions base on location or as guesses by degree for determination of back azimuth.

[dlnorgaard]

For ticket #86 (rotations), take a look at page 95 in the Havskov and Ottemoller processing book, I think you have. Basically, we want to be able to input an earthquake epicenter or other arbitrary coordinates, either directly from a lat/lon input box, or from a location quakeml file, and rotate the horizontal components of a station to be radial and tangential to the azimuth to the epicenter/coords. I imagine this being done in the clipboard primarily but maybe also in the helicorder zoom window. It is primarily used to help make better picks of seismic phases, so I don’t think it’s needed in helicorder view, but maybe (?). I would just start in clipboard only.

If it were me implementing this, I would go to the SAC documentation and source C code and see how they did it:

http://ds.iris.edu/files/sac-manual/commands/rotate.html

Although, their implementation is more generalized than what I described above, which may or may not be desired.

this is a place to start. We can discuss more next week when I get back.

Jeremy

[dlnorgaard]

Once waves are rotated, display them in clipboard, e.g.:

[dlnorgaard]

Spoke to Stephanie (request came from her group) and she thought this was a low priority request. She is also not sure Swarm is necessarily the best place to do this.