aGRVal = log10( N(low_mag) / (10^(-bGRval* low_mag)-10^(-bGR*upper_mag) )
I hope this helps, and for further questions related to the 2013 European seismic hazard model, please use the following contact address: share[at] sed.ethz.ch
Thank you so much Laurentiu for the useful information. Please notice that the incremental occurrence rates that I pasted are relative to magnitude values from Mmin (4.7) to MMax (7.7), so I'm not using the higher values of MMax for which the logic tree approach with different weights is used in the SHARE model.
In this connection, I'd like to understand how I can derive the same occurrence rates with OQ using a different MFD (e.g. the truncGutenbergRichterMFD that is differently defined).
I applied the equation aGRVal = log10 (N (low_mag) / (10^ (-bGRval* low_mag) -10^(-bGR*upper_mag) )
using b=-0.9 and N(low_mag)=0.4595 (Cumulative number of eqks for M>low_mag), and I obtained for this distribution a cumulative a value = 3.8932.
Using b=0.9; a=3.8932, Mmin=4.6 and Mmax=7.8 for the truncGutenbergRichterMFD in OQ, I should obtain the same results of the model with incrementalMFD. But the results for a single site with a single source in terms of UHS and hazard curves are different.
Can you (or other usrers/developers) explain me why? Am I using wrong parameters?
Thanks again for your reply and thanks in advance for your answer!
On Sunday, February 8, 2015 at 10:56:01 PM UTC+1, Paolo Zimmaro wrote:Dear all,
I'm performing calculations using some element of the SHARE PSHA model. In the OQ implementation of this model, I'm noticing that the Magnitude-Frequency distribution of the so-called Area Sources, is given using the "IncrementalMFD". The input of this MFD are: MinMag, binWidth and the occurrence rates.
In my understanding, these occurrence rates represent the list of incremental values for the annual occurrence rates. Is it true?
Below there is the incrementalMFD for a generic source of the SHARE model that I'm using:
<incrementalMFD binWidth="0.2" minMag="4.7">
<occurRates>0.156146154488 0.103164741202 0.0681602685775 0.0450330428636 0.0297530363638 0.0196576361839 0.01298767143 0.00858086941869 0.00566932420314 0.00374568535564 0.00247474977277 0.00163505096033 0.00108026745665 0.000713725630703 0.000471553847881 0.000311552537677</occurRates>
How can I calculate the correspondant (cumulative values for M>0) values (a and b) of the Gutenberg-Richter recurrence law, the Min and Max values that I have to use in OQ?
How can I obtain the same results using the truncGutenbergRichterMFD instead of the incrementalMFD in OQ?
Hopefully someone can help me!
Many thanks in advance.
You received this message because you are subscribed to the Google Groups "OpenQuake Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to openquake-use...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/openquake-users/e2aa70e0-cc5e-4c3b-8122-92e4fd5e42a1n%40googlegroups.com.