BBP CyberShake 2015
Contents
Computational Details
A copy of BBP v15.4 is installed on Blue Waters; /u/sciteam/scottcal/scratch/bbp/15.3.0/bbp/src/gp/WccFormat/Progs In the recent BBP install, find it under <version#>/bbp/src/gp/WccFormat/Pros
We confirmed the version of CVM-S4.26 used for CyberShake Study 15.4 does include the GTL, with a 500 m/s minimum cutoff. It sounds like it would be better to extract Vs30 values from it rather than Wills. Should we apply the 500 m/s cutoff to the Vs30 values we pass to site response like we did with CyberShake, or use them as-is?
Site response module: wcc_siteamp. The current version of the code uses site amplification factors based on the 2014 NGA GMPEs. Check to see if that is on the BBP. This version is not formally validated this version (e.g. by redoing the GP2010 validations).Need to make sure to run some compatibility checks just to make sure the results looked OK.
Should we only do it if the Vs30 for the site is below 600-700 m/s.
Apply the modification to all sites without worrying about the specific Vs30. For sites that have Vs30 greater than about 600-700 the modification will be very minor. But the extra overhead in running the code for all sites is probably insignificant relative to the (equally trivial) overhead in checking the sites for an arbitrary Vs30 threshold and having different processing streams based on this.
Related question - in 2011 we pulled the Vs30 values from Wills. Is that still correct, or should we use Vs30 from the velocity model we used for the CyberShake deterministic (CVM-S4.26)?
There are some concerns about the near-surface velocity values in the CVM used for the previous calcualtions, in particular, very high Vs for rock sites, and that is why we used Wills In CVM-S4.26, does it include the "geotechnical layer"? If so, then its probably best to use these values, so that the LF and HF portions are consistent.
Program Name: wcc_siteamp14.c
The input and output are the same as previous versions with the possible exception being the parameter "model". If "model" is not specified, then the default settings are used, which is fine.
Check to see if this parameter was set previously. (i.e., as model=<something> either in a parfile or on the command line)
Regarding the question of whether we should we apply the 500 m/s cutoff to the Vs30 values we pass to site response like we did with CyberShake, or use them as-is? Current decision is to use them as is. There will be an apparent disconnect with the 500 m/s cutoff at some sites, although the the 500 m/s value with a 100 meter grid spacing is an adequate approximation for the LF calculation.
Priority CyberShake Sites of Interest
Broadband-Cybershake motions for a few sites combining the stochastic and Cybershake signals:
- STNI - basin site
- LADT - basin site
- PAS - rock site
- WNGC - between basins, with expected high ground motions
- LADP - another rock site, near fault
