erf settings

[Blaž Barič]

Hi all, 

I have a question regarding the Earthquake Rupture Forecast calculator settings in the .ini file of a event based analysis. 

Do rupture_mesh_spacing and area_source_discretization parameters influence the number of generated events or do they only influence the locations of the generated events?

Thanks, 

Blaz

[Graeme Weatherill]

Dear Blaz,

Theoretically the rupture_mesh_spacing and area_source_discretization parameters should not necessarily affect the total number of generated events within a stochastic event set. Whilst a lower mesh spacing/discretization will inevitably increase the number of ruptures within the earthquake rupture forecast for a source, the individual probably of each rupture reduces accordingly. Given that the stochastic event set will sample ruptures from their corresponding probabilities, the overall number of ruptures in the SES won't change. However, the SES calculator requires the earthquake rupture forecast to be constructed prior to sampling, so a lower spacing/discretization will increase the computational effort in building the ERF in the first place.

Thanks,

Graeme

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[Blaž Barič]

Hi Graeme, 

thank you very much for your answer.

Kind regards, 

Blaz

[Michele Simionato]

On top of what Graeme says, notice that if you set a spacing/discretization too small, your computation will need a lot more memory and a lot more data will have to be transferred. This is a common mistake, and sometimes a computation become unfeasible just because of that. So, take care.