3.5 Computing the initial temperature structure

Use the boundary conditions temp_top and temp_bot as well as init_temp to achieve a linear T-profile between top and bottom of your domain. Side boundary conditions are always flux-free.

temp_top    = 0
temp_bot    = 1250
init_temp   = 1

To get a steady-state temperature distribution depending on the thermal properties of your materials, you need to specify the thermal parameters k and Cp for all materials and activate the act_steady_temp and act_temp_diff flag.

temp_top        = 0
temp_bot        = 1250
act_steady_temp = 1
act_temp_diff	= 1
...
<MaterialStart>
...
# Thermal parameters	
	k = 3
	Cp = 1000
<MaterialEnd>

To assign an independent temperature to a material (like an intruding magma body), set the thermal parameter T for this material.

temp_top        = 0
temp_bot        = 1250
act_steady_temp = 1
act_temp_diff	= 1
...
<MaterialStart>
...
# Thermal parameters	
	T = 980
<MaterialEnd>

It is possible to allow for a certain amount of temperature diffusion between the anomalous material and its environment before the start of the forward model by using the steady_temp_dt parameter.

temp_top        = 0
temp_bot        = 1250
act_steady_temp = 1
act_temp_diff	= 1
steady_temp_dt  = 0.1
...
<MaterialStart>
...
# Thermal parameters	
	T = 980
<MaterialEnd>

The right slice shows the temperature distribution with additional diffusion, whereas the left slice shows it without.