Isostatic regional/residual calculation for residual-regional separation

Hello everyone
please, I need your help in achieving isostatic regional computation from the topography grid. In my approach, I always obtain an isostatic regional grid which is similar to the topography grid. Surely, I must have made a mistake somewhere.
you can check the different parameters I used from the image attached below.
thank you in advance @BeckyBodger


  • DarrenAndrews
    edited July 2019
    @QuentinMarcANABAFOTZ based on the picture you sent, I think that you are using the wrong Output mode in the Calculate Isostatic Regional Grid dialog; you are using "RootDepth" when you should be using "Isostatic". The "Isostatic" output will generate an isostatic regional grid, whereas the "RootDepth" will generate a grid that defines the depth (in metres below sea level) of the root used to calculate the isostatic regional, which is in effect the depth to the Moho.

    The RootDepth output will resemble the topography you input, because according to Airy isostasy (in which a constant-density crust floats on a higher-density mantle) topography is determined by the thickness of the crust. As a result, topographic highs will correlate with thicker crust (and a deeper RootDepth), so "highs" in the topography grid will correspond with "highs" (=greater depths) in the RootDepth grid. If you compare the actual values of the Root Depth and Topography grids however you should see that they are quite different.

    The isostatic regional should resemble the inverse of the topography, and should also somewhat resemble the regional wavelengths in your Bouguer corrected gravity data.
    Darren Andrews
    Technical Team Manager
    Geosoft logo
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