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I have some set of recorded data in dip direction/dip format. I wish to transform then to strike/dip.

I am currently having a hard time imagining how to convert from dip direction to strike direction. However, it is easier for me to convert from strike direction to dip direction. I am currently using the right hand rule (British), but it seems not to be working well for me. Generally, I have used the index finger as my dip direction and thumb finger as the strike direction.

For example, if I have my strike and dip written as 183/54W, I can conveniently transform this to dip direction and dip using the right hand rule. My thumb will point towards 183 degrees, and then I will position my index to be towards the west of it, this way I can measure the azimuth and record the dip direction to be 273. So, this will be written as 273/54. The nice thing here is that I can transform 273/54 back to 183/54W, by simply putting my index finger back to 273, and my thumb will be 90 degrees away from it, thereby, making it 183.

In the second case, I have a data reading 126/33NE in the strike dip format. I have transformed this to dip direction and dip format by putting my thumb finger towards 126 degrees, and by making my index finger to be towards E (This was in an awkward way, because I had to place my index over my thumb in a 90 degree manner). In this way, I will subtract 90 from 126, and get 36 degrees. This will then be written as 036/33. However, if I do try to revert from 036/33, assuming that I had no prior knowledge of the original 126/33NE and using the right hand rule appropriately, I will have my thumb pointing toward 306 degrees. Then, the result will be written as 306/33NE. There has been a 180 degree shift in the recorded value.

What could I be doing wrong? If there a better way to make this conversion? Thanks a lot in advance for your response.

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  • $\begingroup$ To my way of thinking it doesn't matter whether the strike is 126/33 or 306/33. The difference between the two is due to which way the compass was pointing when the measurement was taken. $\endgroup$ – Fred Sep 21 at 3:25
  • $\begingroup$ Thanks Fred, I figured out it is true. I actually wanted to plot my data on a stereonet, and trying either of the strike angle leads me to have the same results. Many thanks once again for your response. $\endgroup$ – Itunu Sep 24 at 23:15

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