Apply Faults to Grid

This command is used to offset the grid values of an existing strata elevation grid file to adjust for faults. The program saves a new grid file with the values offset based on the fault lines drawn with the Draw Fault Line command. There are two methods. The Separate Grids For Each Side of Fault method applies for thrust or reverse faults where the strata are folded over top of themselves within the fault zone. In this case, the strata can be modeled separately for each side of the fault. The Adjust Grid Across Fault applies when the strata can be modeled with the same grid for the whole site. This method adjusts the grid in the fault zone.

Separate Grids For Each Side of Fault

Before running Apply Faults to Grid for this method, setup the faults and strata grids as follows:
1. Draw a fault polyline with the dip angle and elevation difference set using the Draw Fault Line command.
2. Draw a closed polyline around the area on the high side of the fault.
3. Create strata grids like usual. Make separate strata grids for the high and low sides.
4. Create a surface topo grd as usual.

Then run Apply Faults To Grid. The program prompts for the fault polyline and high side polyline from steps 1,2 and the grids from steps 3,4. The processing for the high side strata grids is slightly different than the low side because the way the program goes about embedding the fault surface to the strata surfaces. For the high side, you specify one strata grid at a time. For the low side, you specify the top and bottom strata grids (ie A1_TOP.grd and A1_KEY.grd).

Adjust Grid Across Fault

The Fault Influence Distance is the offset distance away from the faultlines that will be used to transition from the original grid to the faulted values.

This is the grid before applying the faults

This is the grid after applying the faults

Prompts