Tectonic related parameters

Tectonic forcing parameters

Declaration example:

tectonics:
    - start: -20000000.
      end: -19000000.
      upsub: ['data/uplift20Ma','t']
    - start: -18000000.
      end: -17000000.
      upsub: ['data/uplift18Ma','t']
      hdisp: ['data/hdisp18Ma', 'hxyz']

It defines the tectonic forcing conditions from a sequence of events defined by a starting and ending time (start and end) and either a vertical rate only forcing (e.g. uplift and/or subsidence defined with upsub) or a fully 3D displacement rate hdisp. These displacement rates are set in metres per year.

Important

For horizontal advection the user needs to define the advect key in the domain section of the input file. The advection scheme could either be upwind, iioe1, iioe2 or interp (go to the technical information in the documentation for more information).

Important

Here again, these forcing files are defined as numpy zip array (.npz). These files use specific keys to identify the tectonic forcing that are specified by the user in the input file. For vertical only condition, the displacements (in m/yr) is a 1D vector with values on each node of the grid. For the horizontal condition, the key is a 3D array containing the displacement rates along the x, y and z axis (in m/yr). When the horizontal advection is for 2D grids, the provided displacements also need to be in 3D but with the third dimension set to 0.0.

Note

There is no requirement to impose continuous tectonics forcing and you might chose to have periods without displacement by making discontinuous events using the start and end keys.

Note

When applying horizontal displacement using the interp scheme (mainly used in global simulation to represent plate movements), the horizontal movements are performed at the end of the period (i.e., at the specified end time). In the other cases, the horizontal displacement is done at every timestep (specified by dt).

Flexural isostasy definition

This function computes the flexural isostasy equilibrium based on topographic change. It accounts for flexural isostatic rebound associated with erosional loading/unloading.

Important

It is computed on a regular grid (in X,Y in 2D or lon/lat for global simulation) and is limited in terms of parallelisation.

Declaration example:

flexure:
  method: 'FD'
  regdx: 1000.
  ninterp: 4
  thick: 30.e3
  rhoc: 2300.0
  rhoa: 3300.0
  young: 65e9
  nu: 0.25
  bcN: "Mirror"
  bcE: "0Slope0Shear"
  bcS: "Mirror"
  bcW: "0Slope0Shear"

Used to consider flexural isostasy (i.e. not global scale) where:

1. method: the approach used is either ‘FD’ in 2D or ‘global’ for global model.

2. regdx: the resolution of the regular grid used to perform the flexural isostasy calculation,

3. ninterp: the number of points used to perform the interpolation between goSPL unstructured mesh and the regular grid (not used for the ‘global’ method)

4. thick effective elastic plate thickness in m,

5. rhoc crust density in kg/m3,

6. rhoa asthenospheric density in kg/m3.

7. young Young’s Modulus in Pa.

8. nu Poisson ratio.

9. bcN, bcE, bcS, bcW North, East, South and West boundary conditions.

Note

For non-global simulation, the user needs to specify the boundary conditions for the flexural isostasy calculation. Similar conditions to gFlex are possible:

• 0Displacement0Slope 0-displacement-0-slope boundary condition

• 0Moment0Shear: Broken plate boundary condition second and third derivatives of vertical displacement are 0. This is like the end of a diving board.

• 0Slope0Shear: First and third derivatives of vertical displacement are zero. While this does not lend itsellf so easily to physical meaning, it is helpful to aid in efforts to make boundary condition effects disappear (i.e. to emulate the NoOutsideLoads cases)

• Mirror: Load and elastic thickness structures reflected at boundary.

• Periodic`: Wrap-around boundary condition: must be applied to both North and South and/or both East and West. This causes, for example, the edge of the eastern and western limits of the domain to act like they are next to each other in an infinite loop.

Warning

In case where flexure and orographic rain capabilities are defined in the same simulation, you will need to have the same grid resolution (regdx) for each definition.

In addition, it is possible to define variable lithospheric elastic thicknesses by using the temap key below where specific maps could be added through time during the run.

Declaration example:

temap:
  - start: 250.e6
    map: ['input/temap1', 'te']
  - start: 251.e6
    map: ['input/temap2', 'te']

Here again, the elastic maps files are provided as numpy zip array (.npz).