Hi all!

Happy new year! I want to add a viscosity jump (~30) at 660 km in a 2D model. How should I implement it? I would really appreciate it if anyone with experience could help me with this.

Also, It would be much appreciated if anyone could help answer how to plot simple profiles like the viscosity profile in aspect. I tried using “plot over line” in ParaView. But if there’s a more convenient or easier way to do this, please let me know. It would also be better if there’s an easy way to draw diffusion and dislocation viscosity separately if we use the “diffusion dislocation” material model. Thank you very much!

Cheers

Ziqi

Hi Ziqi,

I want to add a viscosity jump (~30) at 660 km in a 2D model. How should I implement it?

That depends a bit on the material model you use. Many material models either have phase transition, or a viscosity profile that is depth-dependent. Both would allow you to add a viscosity jump.

Alternatively, using the “Depth dependent model” as your material model allows you to use a different model as the base model and then change the depth-dependence of your viscosity.

how to plot simple profiles like the viscosity profile in aspect

This also depends on what exactly you want to plot. “plot over line” in ParaView is a good and simple option. If you want to plot a 1D profile of average properties in your model, you can instead also use the “Depth average” postprocessor.

It would also be better if there’s an easy way to draw diffusion and dislocation viscosity separately if we use the “diffusion dislocation” material model.

That’s a great idea! If you want to implement this, the way to do that would be to use the `NamedAdditionalMaterialOutputs`

as it is done in some other material models such as the grain size material models.

Best,

Juliane

Hi Juliane,

Thank you very much for your timely and helpful response!

One follow-up question: If I want to add a viscosity jump and consider both dislocation and diffusion at the same time, can I add “depth dependent” and “diffusion dislocation” in the material model at the same time? Thank you very much!

Cheers

Ziqi

Hi Ziqi,

You can only ever use one material model at the same time, but within the depth-dependent model, you can specify a base model that is being used to compute all material properties, and the depth-dependence is then applied at the end. So in other words, in that case you will need to use “depth dependent” as your material model.

Best,

Juliane

Thank you very much! I will give it a try!

Cheers

Ziqi

Dear Juliane,

I hope that you are doing well. Thanks for your kind suggestions earlier! However, when I tried to implement the material model as follows:

subsection Material model

set Model name = depth dependent

subsection Depth dependent model

set Base model = diffusion dislocation

set Depth dependence method = File

set Data directory = /home/mazq/software/aspect/aspect/data/material-model/depth-dependent/

set Viscosity depth file = visc_depth.txt

set Reference viscosity = 1e21

end

subsection Diffusion dislocation model # line 84

set Reference viscosity = 1e21

end

end

And the visco_depth.txt looks like this:

#
Test data for ascii data reference state

#
Only next line is parsed in format: [nx] because of keyword “POINTS:”

#
POINTS: 4

#
Columns: depth (m), viscosity (Pa.s)

depth viscosity

0.0000000e+00 5.8000000e+21

0.6700000e+06 5.8000000e+21

0.6710000e+06 1.7000000e+23

1.5000000e+06 1.7000000e+23

The code failed and sent off the error message:

Line <84> of file <input string: There is no such subsection to be entered: Material model.Diffusion dislocation model

I tried to use “set List of model names = depth dependent, diffusion dislocation”, which didn’t work as well.

Could you please help me with this? I would really appreciate it! Thank you very much!

Cheers

Ziqi

Hi Ziqi,

You have the wrong name for the subsection. It’s just called `subsection Diffusion dislocation`

. You can find the names of all parameters and section listed here:

https://aspect.geodynamics.org/doc/parameter_view/parameters.xml

-Juliane

Hi Juliane,

Thank you! It worked now!

Cheers

Ziqi