Greg Springer of WVACS has developed an easy method for measuring strike and dip in a cave using a DistoX. See his email below, forwarded with permission.
Mark Minton ---------------------------- Original Message ---------------------------- Subject: Measuring Strike and Dip With a DistoX From: "Greg wvdirtboy" <wvdirt...@gmail.com> Date: Sat, August 22, 2015 3:41 pm -------------------------------------------------------------------------- Measuring Strike and Dip with a DistoX2 By Greg Springer Cave development is strongly influenced by folds and faults. Caves passages often trend parallel to folds or, as a geologist would say, along "strike". And, just as often, cave passages will go down the side of a fold or, more properly, "down dip". Knowing the strike and dip of rocks is quite useful for inferring where to dig or look for suspected passages. As a result, cavers sometimes measure strike and dip using Bruntons or similar instruments, but few cavers own Bruntons or know where to steal one. Fortunately, measuring strike and dip can now easily and accurately be measured with a DistoX or X2 and the number of DistoXs in circulation has skyrocketed in recent years. The measurement process is simple: 1. Find an exposed bedding surface (top or bottom of a rock bed). See diagram here: https://www.flickr.com/photos/ilikegooglebetter/20607560279 2. Pick a spot on the bedding surface, take a shot, and write down the result (all three numbers). 3. Hold the DistoX at the same location as was used for the first shot, but shoot a foot or more away from the first (see diagram). Widely spaced points will usually yield a more reliable result because they average across roughness on the measured surface. 4. Pick and shoot a third spot such that the three points form a triangle. 5. After the trip, download an Excel workbook from the West Virginia Association for Cave Studies at http://www.wvacs.org/files/3PointStrikeAndDip.xlsx (just type the address into your browser). 6. Enter the three unprocessed shots into the worksheet labeled "From DistoX Shots" and the strike and dip values will automatically appear in highlighted cells. Alternatively, you can enter the shots into your cave database program of choice and enter the NEZ coordinates of the shots (stations) into a second worksheet provided ("From NEZ Coordinates") in the file. There are no formulas to enter; just type the shots in the indicated cells. It is as simple as that, but don't forget to adjust the strike for magnetic declination. Curious minded people can view the formulas in the Excel spreadsheet if they want the gory mathematical details of the procedure. Those who sketch with tablets may want to adapt the math or spreadsheet such that it will run in an app and thus allow strike and dip values to be obtained while still underground. Enjoy! Greg Springer
Measuring Strike and Dip with a DistoX2
By Greg SpringerCave development is strongly influenced by folds and faults. Caves passages often trend parallel to folds or, as a geologist would say, along âstrikeâ. And, just as often, cave passages will go down the side of a fold or, more properly, âdown dipâ. Knowing the strike and dip of rocks is quite useful for inferring where to dig or look for suspected passages. As a result, cavers sometimes measure strike and dip using Bruntons or similar instruments, but few cavers own Bruntons or know where to steal one.
Fortunately, measuring strike and dip can now easily and accurately be measured with a DistoX or X2 and the number of DistoXs in circulation has skyrocketed in recent years. The measurement process is simple:
1. Â Â Find an exposed bedding surface (top or bottom of a rock bed).
See diagram here:Â https://www.flickr.com/photos/ilikegooglebetter/20607560279
2. Â Â Pick a spot on the bedding surface, take a shot, and write down the result (all three numbers).
3. Â Â Hold the DistoX at the same location as was used for the first shot, but shoot a foot or more away from the first (see diagram). Widely spaced points will usually yield a more reliable result because they average across roughness on the measured surface.
4. Â Â Pick and shoot a third spot such that the three points form a triangle.
5. Â Â After the trip, download an Excel workbook from the West Virginia Association for Cave Studies at http://www.wvacs.org/files/3PointStrikeAndDip.xlsx (just type the address into your browser).
6. Â Â Enter the three unprocessed shots into the worksheet labeled âFrom DistoX Shotsâ and the strike and dip values will automatically appear in highlighted cells. Alternatively, you can enter the shots into your cave database program of choice and enter the NEZ coordinates of the shots (stations) into a second worksheet provided (âFrom NEZ Coordinatesâ) in the file. There are no formulas to enter; just type the shots in the indicated cells. It is as simple as that, but donât forget to adjust the strike for magnetic declination.
Curious minded people can view the formulas in the Excel spreadsheet if they want the gory mathematical details of the procedure. Those who sketch with tablets may want to adapt the math or spreadsheet such that it will run in an app and thus allow strike and dip values to be obtained while still underground. Enjoy!
Â
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Greg Springer
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