[CIG-SHORT] Initial condition

[Brad Aagaard]

See the PyLith manual for the implementation of rate-state friction in 
PyLith. We regularize the approach to zero slip rate differently than 
many other formulations in order to allow use of an iterative solver 
(which a nonzero tolerance) in quasi-static problems. You should be able 
to take this into account and setup your problem to start in equilibrium 
with zero displacement and slip rate.

For dynamic problems I have been able to use zero velocity and slip rate 
initial conditions with the fault in equilibrium in solving the SCEC 
dynamic rupture benchmark problems. Of course, in these cases we are 
focused on the rupture behavior in which the slip rates are many orders 
of magnitude larger than the steady state values.

Regards,
Brad


On 02/07/2014 01:01 PM, Ma, Xiao wrote:
> Hi,
> Forgive me for not following you , are you saying that I first set up a model and give its boundary condition , then get the response (displacement and velocity)? Because I am using the rate and state friction, as you know everything is moving in this application of friction law, because the logarithm term , we can't have a zero velocity .
> Best,
> Xiao
> ________________________________________
> From: Brad Aagaard [baagaard at usgs.gov]
> Sent: Friday, February 07, 2014 14:54
> To: cig-short at geodynamics.org; Ma, Xiao
> Subject: Re: [CIG-SHORT] Initial condition
>
> PyLith currently assumes zero initial displacement and velocity for the
> solution. You can use the elastic prestep to compute an initial
> displacement field resulting from the elastic response to a given set of
> boundary conditions.
>
> Regards,
> Brad
>
> On 02/07/2014 12:47 PM, Ma, Xiao wrote:
>> Hi,
>> I want to know how to apply initial condition(like initial displacement and velocity) in pylith , is it the same as applying the boundary condtion?
>> Can you give me some examples?
>> Best,
>> Xiao
>>
>>
>>
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>