Importing fault data question


I am curious what is a fairly quick way to import 3d fault data in ASCII (. Asc) format?

Playing around with the idea of converting the fault surfaces into simplified contour representations similar to what is shown in the PyLith Tutotial on Meshing (screen shot attached) using vertices to make a surface.

Not sure if this would work.

It depends on the type of fault data. Is it a set of (x,y,z) coordinates, a set of profiles, or a set of contours? If it is a set of profiles or contours, it would be very easy to translate the points into a set of lines in Trelis, and then create a skin surface (you could use a Python or other script to do this). Otherwise, you might need to create your own contours (you could use GMT for this).

Thanks. I believe it’s termed gridded elevation data, so just Z, but in utm.

In Matlab, I had to space out the xllcorner and yllcorner by a given cell-size.

Is that like (x, y, z)?

This will depend on the nature of the fault. Is it rectangular in map view (e.g., does it fill the entire grid)? If so, it would be trivial to convert your points to a set of lines or intersecting lines. Otherwise, you will need to define the fault boundaries and create curves within those.

Thank you for your help.

I have converted the gridded-elevation data into a series of x,y,z coords, somewhat similar to that used in the tutorial with the file.

My z values are all different, whereas in the code in the YouTube video, they were grouped by 5’s as contours as I understand it. Currently the data is in utm, though I imagine that doesn’t make a huge difference. I only have a handful of faults I want to include.

Can that code be adapted easily? Or should I just abandon it as I don’t have contours I don’t have experience with Python

This is very difficult to answer without knowing more about your problem. The Python script in the examples creates a skin surface from a set of contours. If you want to use it with minimal (or no) modification, you would need to provide a set of contours in a format similar to the cas_contours file. If you are using Matlab, I’m sure there’s a way to generate a set of contours and output them to a file. Otherwise, you could read the (x,y,z) coordinates into GMT and generate the contours that way.

Your final alternative, if you’re comfortable with Matlab, is to just do everything in there. All you need to do is produce the journal files that form the curves, and then use the curves to generate a skin surface.