initial production of cb19 IA and CAV.

[emabcede30]

I have issue with calc of phi for total aleatory stddev. I want to know which is the correct formula for phi.

phi equation in CB14:

$$\phi = \sqrt{\phi_{\ln(Y_B)}^2 + \phi_{\ln(AF)}^2 + \alpha^2 \phi_{\ln(\text{PGA}_B)}^2 + 2\alpha\rho_{\ln(\text{PGA}),\ln(Y)} \phi_{\ln(Y_B)} \phi_{\ln(\text{PGA}_B)}}$$

phi equation in CB19 spreadsheet:

$$\phi = \sqrt{\phi_{\ln(Y)}^2 + \alpha^2 \phi_{\ln(\text{PGA})}^2 + 2\alpha\rho_{\ln(\text{PGA}),\ln(Y)} \phi_{\ln(Y)} \phi_{\ln(\text{PGA})}}$$

spreadsheet in cb19:
https://journals.sagepub.com/doi/suppl/10.1193/090818EQS212M/suppl_file/10_eeri_35_3_suppl_es1_online.xlsx

spreadheet in cb14:
https://journals.sagepub.com/doi/suppl/10.1193/100614EQS151M/suppl_file/14_eeri_32_2_suppl1_es1-es1_online.xlsx

Reference:

Bozorgnia, Y., & Campbell, K. W. (2016). Ground motion model for the vertical-to-horizontal (V/H) ratios of PGA, PGV, and response spectra. Earthquake Spectra, 32(2), 951-978.

Campbell, K. W., & Bozorgnia, Y. (2014). NGA-West2 ground motion model for the average horizontal components of PGA, PGV, and 5% damped linear acceleration response spectra. Earthquake Spectra, 30(3), 1087-1115.

Campbell, K. W., & Bozorgnia, Y. (2019). Ground motion models for the horizontal components of Arias intensity (AI) and cumulative absolute velocity (CAV) using the NGA-West2 database. Earthquake Spectra, 35(3), 1289-1310.

[ftbernales]

$$ \phi = \sqrt{\phi_{\ln(Y_B)}^2 + \phi_{\ln(AF)}^2 + \alpha^2 \phi_{\ln(\text{PGA}B)}^2 + 2\alpha\rho{\ln(\text{PGA},\ln(Y))} \phi_{\ln(Y_B)} \phi_{\ln(\text{PGA}_B)}} $$

$\phi$ equation in CB14:
$$\phi = \sqrt{ \phi_{\ln(Y_{B})}^2 + \phi_{\ln(AF)}^2 + \alpha^{2}\phi_{\ln(PGA_{B})}^2 + 2\alpha\rho_{\ln(PGA),\ln(Y)}\phi_{\ln(Y_{B})}\phi_{\ln(PGA_{B})} }$$

$\phi$ equation in CB19 spreadsheet:
$$\phi = \sqrt{ \phi_{\ln(Y)}^2 + \alpha^{2}\phi_{\ln(PGA)}^2 + 2\alpha\rho_{\ln(PGA),\ln(Y)}\phi_{\ln(Y)}\phi_{\ln(PGA)} }$$

[micheles]

Notice that we have strict conventions on the naming of the modules, this is why you get the error

RuntimeError: /home/runner/work/oq-engine/oq-engine/openquake/hazardlib/gsim/campbell_bozorgnia_2019_IA_CAV.py is not lowercase!

You need to change the name of the module to campbell_bozorgnia_2019_ia_cav.py

[micheles]

Now you have an error /doc/api-reference/openquake.hazardlib.gsim.rst: campbell_bozorgnia_2019_ia_cav.py is not documented. The solution is to update the file /doc/api-reference/openquake.hazardlib.gsim.rst

[emthompson-usgs]

Hi @emabcede30, @kslytherin has been working on an implementation of this also. It is unfortunate that we've duplicated effort a bit. One difference is that he added the new metrics within the existing CB14 module rather than creating a new one for these metrics, as discussed here.

@mmpagani @micheles Any thoughts on how we should proceed? We can abandon our implementation if the approach in this merge request is fine.

[kslytherin]

I have issue with calc of phi for total aleatory stddev. I want to know which is the correct formula for phi.

phi equation in CB14:

phi equation in CB19 spreadsheet:

spreadsheet in cb19: https://journals.sagepub.com/doi/suppl/10.1193/090818EQS212M/suppl_file/10_eeri_35_3_suppl_es1_online.xlsx

spreadheet in cb14: https://journals.sagepub.com/doi/suppl/10.1193/100614EQS151M/suppl_file/14_eeri_32_2_suppl1_es1-es1_online.xlsx

Reference:

Bozorgnia, Y., & Campbell, K. W. (2016). Ground motion model for the vertical-to-horizontal (V/H) ratios of PGA, PGV, and response spectra. Earthquake Spectra, 32(2), 951-978.

Campbell, K. W., & Bozorgnia, Y. (2014). NGA-West2 ground motion model for the average horizontal components of PGA, PGV, and 5% damped linear acceleration response spectra. Earthquake Spectra, 30(3), 1087-1115.

Campbell, K. W., & Bozorgnia, Y. (2019). Ground motion models for the horizontal components of Arias intensity (AI) and cumulative absolute velocity (CAV) using the NGA-West2 database. Earthquake Spectra, 35(3), 1289-1310.

@emabcede30 I have emailed Yousef Bozorgnia on the phi discrepency. He has informed Kenneth Campbell on the issue and I am currently waiting for a response.

[mmpagani]

Thank you for this work and sorry for the late comment. As suggested by @emthompson-usgs I would find it more useful for the user to have these intensity measures (IMTs) added to the original model rather than into a separate GMM implementation. The advantage is that in a single hazard analysis, the user can compute hazard for the already-supported IMTs and the new ones you are currently adding. We are keen to help with the refactoring. Maybe you can also leverage from the draft implementation from Eric.

[ftbernales]

Hi, @emthompson-usgs. Thanks for the heads up. The reason for this approach in implementation by my colleague @emabcede30 is the difference in the cross-correlation coefficient $\rho_{\ln(PGA),\ln(Y)}$ between CB14 and CB19 (you can verify this by simply comparing the "HOR_Coeffs" sheets in their respective supplementary Excel files). Even though the median estimates stay the same, the inter-event standard deviations $\phi$ are different between CB14 and CB19. In relation to this, we actually thought of including the updated CB19 GSIM for RotD50 PGA & Sa in this PR as well; fortunately, this discussion has been already brought up.

Regardless, thanks @kslytherin for reaching out to the GMM developers directly. I think their response will bring more clarity to our final direction.

I would like to request for further advice, @mmpagani @micheles, given these additional considerations/constraints. Thanks!

[emthompson-usgs]

Unfortunately, @kslytherin is out of the office and won't be back for a while. I will point out that his draft changes to the CB14 model are on a branch on his fork of the repo here:
https://github.com/kslytherin/oq-engine/blob/new-models/openquake/hazardlib/gsim/campbell_bozorgnia_2014.py

@ftbernales I see what you mean about rho. For the 2019 model, it is a function of magnitude, and in 2014 it is just a constant. If I'm not mistake, the CampbellBozorgnia2019_IA_CAV implementation in this PR inherits from the GMPE class and so it isn't taking advantage of the code that could be re-used. We could have a 2019 class that at least inherits from the 2014 class and only changes the method for computing rho. This seems like a better design to me, but I'm less familiar with the full implications for the hazard calculations so I defer to @mmpagani.

[mmpagani]

Dear Francis, Eric and Enrico thanks for your comments (@ftbernales @emthompson-usgs @emabcede30).

I downloaded the implementation of @kslytherin and the one of @emabcede30 and compared the two. Indeed the differences between the implementations (and the current CB14 implementation) are minor apart from a few details.

Some notes below:

• I prefer the option adopted by @emabcede30 for the initialization of variables used here

  oq-engine/openquake/hazardlib/gsim/campbell_bozorgnia_2019_ia_cav.py

  Line 419 in 7e8a0ed

  self.estimate_ztor = int(kwargs.get('estimate_ztor', 0))

• The two implementations of the function computing rho are quite similar so you can pick one of the two (

  oq-engine/openquake/hazardlib/gsim/campbell_bozorgnia_2019_ia_cav.py

  Line 419 in 7e8a0ed

  self.estimate_ztor = int(kwargs.get('estimate_ztor', 0))

  or https://github.com/kslytherin/oq-engine/blob/new-models/openquake/hazardlib/gsim/campbell_bozorgnia_2014.py#L305)

To complete the implementation, I suggest using the current implementation of CB14 without creating a new class.

• Update the supported IMTs (with the ones added here

  oq-engine/openquake/hazardlib/gsim/campbell_bozorgnia_2019_ia_cav.py

  Line 392 in 7e8a0ed

  DEFINED_FOR_INTENSITY_MEASURE_TYPES = {CAV, IA}

  )
• Add at this point (https://github.com/gem/oq-engine/blob/master/openquake/hazardlib/gsim/campbell_bozorgnia_2014.py#L461)
  something like this

if imt.string in ['CAV', 'IA']:
   .... compute phi as in CB19
else:
   .... compute phi as before

• Update coeff tables
• Use the verification tables and tests for the new IMTs as already prepared by @emabcede30 and @ftbernales

... I hope I got everything with this. I will be glad to examine it further otherwise. Many thanks again. Marco