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Hazard Disaggregation#

The OpenQuake engine outputs for a disaggregation analysis correspond to projections of the multidimensional probability matrix containing the results of the disaggregation. The currently available projections are 11:

  1. Mag

  2. Dist

  3. Mag_Dist

  4. Mag_Dist_Eps

  5. Lon_Lat

  6. Mag_Lon_Lat

  7. TRT

  8. TRT_Mag

  9. TRT_Lon_Lat

  10. TRT_Mag_Dist

  11. TRT_Mag_Dist_Eps

The user can specify the desired projects in the job.ini file by setting the parameter disagg_outputs. In the disaggregation demo the parameter is not set, so all possible outputs are generated. The demo specifies the parameter individual_rlzs = true, therefore the results are available for each realization. This is fine for the demo, where there are only 2 realizations, but in general specifying individual_rlzs is a bad idea, since most models have thousands of realizations and you would end up exporting a huge amount of data, with the risk of running out of memory.

By default the engine only export the mean disaggregation. However, when interested to a specific realization, the user can specify the realization on which to perform the disaggregation by setting the rlz_index parameter in the job.ini file.

NB: before version 3.17 the default algorithm used was different: only the realization closest to the mean hazard curve was selected and used perform the disaggregation. This was a choice forced by performance limitations that do not apply to recent versions of the disaggregation calculator, which instead is able to compute all realizations and then perform a weighted mean of the probabilities.

For the disaggregation demo the list of outputs are the following:

user@ubuntu:~$ oq engine --lo <calc_id>
id | name
1156 | Disaggregation Outputs Per Realization
1157 | Statistical Disaggregation Outputs
1158 | Full Report
1159 | Hazard Curves
1160 | Realizations

Running --export-output to export the disaggregation results will produce individual files for each site. Since the demo considers 2 sites you will get 2 x 11 = 22 files for the statistical outputs:

  1. Dist-mean-0_<calc_id>.csv

  2. Dist-mean-1_<calc_id>.csv

  3. Lon_Lat-mean-0_<calc_id>.csv

  4. Lon_Lat-mean-1_<calc_id>.csv

  5. Mag-mean-0_<calc_id>.csv

  6. Mag-mean-1_<calc_id>.csv

  7. Mag_Dist-mean-0_<calc_id>.csv

  8. Mag_Dist-mean-1_<calc_id>.csv

  9. Mag_Dist_Eps-mean-0_<calc_id>.csv

  10. Mag_Dist_Eps-mean-1_<calc_id>.csv

  11. Mag_Lon_Lat-mean-0_<calc_id>.csv

  12. Mag_Lon_Lat-mean-1_<calc_id>.csv

  13. TRT-mean-0_<calc_id>.csv

  14. TRT-mean-1_<calc_id>.csv

  15. TRT_Lon_Lat-mean-0_<calc_id>.csv

  16. TRT_Lon_Lat-mean-1_<calc_id>.csv

  17. TRT_Mag-mean-0_<calc_id>.csv

  18. TRT_Mag-mean-1_<calc_id>.csv

  19. TRT_Mag_Dist-mean-0_<calc_id>.csv

  20. TRT_Mag_Dist-mean-1_<calc_id>.csv

  21. TRT_Mag_Dist_Eps-mean-0_<calc_id>.csv

  22. TRT_Mag_Dist_Eps-mean-1_<calc_id>.csv

Alternatively, you can use the commands

user@ubuntu:~$ oq export disagg-rlzs <calc_id>
user@ubuntu:~$ oq export disagg-stats <calc_id>

which will produce the same files as the usual --export-outputs. For instance the disaggregation by magnitude will produce files like the following for the realizations:

#,,,,,"generated_by='OpenQuake engine 3.20.0-git41d16a6e0a'...
imt,iml,poe,mag,rlz1,rlz0
PGA,2.22492E-01,1.00000E-01,5.50000E+00,4.30692E-02,4.30692E-02
PGA,2.22492E-01,1.00000E-01,6.50000E+00,5.97611E-02,5.98033E-02
PGA,2.22492E-01,1.00000E-01,7.50000E+00,2.44507E-04,4.68981E-04
PGA,1.69922E-01,2.00000E-01,5.50000E+00,1.05186E-01,1.05186E-01
PGA,1.69922E-01,2.00000E-01,6.50000E+00,1.06652E-01,1.06838E-01
PGA,1.69922E-01,2.00000E-01,7.50000E+00,7.87177E-04,1.41027E-03

The demo contains 3 magnitude bins and poes_disagg = 0.1 0.2, so there are 6 lines in the CSV. There is a column for each realization but they are not ordered.

The statistical exporter will produce the following for the means:

,,,,"generated_by='OpenQuake engine 3.20.0-git41d16a6e0a'...
imt,iml,poe,mag,mean
PGA,2.22492E-01,1.00000E-01,5.50000E+00,4.30692E-02
PGA,2.22492E-01,1.00000E-01,6.50000E+00,5.97864E-02
PGA,2.22492E-01,1.00000E-01,7.50000E+00,3.79197E-04
PGA,1.69922E-01,2.00000E-01,5.50000E+00,1.05186E-01
PGA,1.69922E-01,2.00000E-01,6.50000E+00,1.06764E-01
PGA,1.69922E-01,2.00000E-01,7.50000E+00,1.16108E-03

Most users will expect the disaggregation results to be in the traditional form of Bazzurro and Cornell, 1999. However, the engine does not follow that tradition, as explained in the science manual. Still, we provide a command to export the disaggregation results in the traditional form. Simply write

user@ubuntu:~$ oq export disagg-rlzs-traditional <calc_id>

For instance for the realization magnitude output you will get

#,,,,,"generated_by='OpenQuake engine 3.20.0-git41d16a6e0a'...
imt,iml,poe,mag,rlz1,rlz0
PGA,2.22492E-01,1.00000E-01,5.50000E+00,4.15754E-01,4.14699E-01
PGA,2.22492E-01,1.00000E-01,6.50000E+00,5.81937E-01,5.80882E-01
PGA,2.22492E-01,1.00000E-01,7.50000E+00,2.30935E-03,4.41874E-03
PGA,1.69922E-01,2.00000E-01,5.50000E+00,4.94599E-01,4.92775E-01
PGA,1.69922E-01,2.00000E-01,6.50000E+00,5.01897E-01,5.00967E-01
PGA,1.69922E-01,2.00000E-01,7.50000E+00,3.50451E-03,6.25733E-03

In the traditional format the probabilities compose to 1.0 while in the engine format the probabilities compose to the PoE listed in poes_disagg.

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