Classical PSHA#
By default, the classical PSHA calculator computes and stores hazard curves for each logic tree sample considered.
When the PSHA input model doesn’t contain epistemic uncertainties the results is a set of hazard curves (one for each
investigated site). The command below illustrates how it is possible to retrieve the group of hazard curves obtained for
a calculation with a given identifier <calc_id> (see Section Exporting results from a hazard calculation
for an explanation about how to obtain the list of calculations performed with their corresponding ID):
user@ubuntu:~$ oq engine --lo <calc_id>
id | name
3 | Hazard Curves
4 | Realizations
To export from the database the outputs (in this case hazard curves) contained in one of the output identifies, one can do so with the following command:
user@ubuntu:~$ oq engine --export-output <output_id> <output_directory>
Alternatively, if the user wishes to export all of the outputs associated with a particular calculation then they can
use the --export-outputs with the corresponding calculation key:
user@ubuntu:~$ oq engine --export-outputs <calc_id> <output_directory>
The exports will produce one or more CSV files containing the seismic hazard curves as represented in the listing <lst:output_hazard_curves_csv>` below.
1#,,,,,"generated_by='OpenQuake engine 3.18.0', start_date='2023-10-03T06:09:08', checksum=2107362341, kind='mean', investigation_time=1.0, imt='PGA'"
2lon,lat,depth,poe-0.1000000,poe-0.4000000,poe-0.6000000
30.00000,0.00000,-0.10000,4.553860E-01,5.754042E-02,6.354511E-03
40.10000,0.00000,-0.10000,1.522632E-01,0.000000E+00,0.000000E+00
50.20000,0.00000,-0.10000,3.037810E-03,0.000000E+00,0.000000E+00
60.30000,0.00000,-0.10000,0.000000E+00,0.000000E+00,0.000000E+00
Notwithstanding the intuitiveness of this file, let’s have a brief overview of the information included. The overall content of this file is a list of hazard curves, one for each investigated site, computed using a PSHA input model representing one possible realisation obtained using the complete logic tree structure.
The first commented line contains some metadata like the version of the engine used to generate the file, the start date of the calculation, a checksum, the kind of hazard curves generated (in the example they are mean curves), the investigation time and the IMT used (in the example PGA).
The header line indicates the contents of each column, beginning with the
site coordinates (lon, lat, and depth) and then one column corresponding
to each intensity measure level (IML) specified in the job file for the
given IMT. These columns are named using the format poe-<IML> to be
interpretted as the probability that the IMT will exceed the given IML
during the investigation time. Each row then gives - for one site - the
probabilities of exceedance associated with each of the IMLs.
If the hazard calculation is configured to produce results including seismic hazard maps and uniform hazard spectra, then the list of outputs would display the following:
user@ubuntu:~$ oq engine --lo <calc_id>
id | name
2 | Full Report
3 | Hazard Curves
4 | Hazard Maps
5 | Realizations
6 | Uniform Hazard Spectra
The first listing below shows a sample of the CSV file used to describe a hazard map, and and the second listing below shows a sample of the CSV used to describe a uniform hazard spectrum. In both cases, the files contain a commented line as in the hazard curve. The following row has the column headers: the site coordinates (lon, lat), and then a set of two-part column names that indicate the IMT and probability of exceedance corresponding to the investigation time; the remaining rows give the values for each site.
1#,,,,"generated_by='OpenQuake engine 3.18.0', start_date='2023-10-03T06:09:09', checksum=969346546, kind='mean', investigation_time=1.0"
2lon,lat,PGA-0.002105,SA(0.2)-0.002105,SA(1.0)-0.002105
3-123.23738,49.27479,3.023730E-03,1.227876E-02,1.304533E-02
4-123.23282,49.26162,2.969411E-03,1.210481E-02,1.294509E-02
5-123.20480,49.26786,2.971350E-03,1.211078E-02,1.294870E-02
1#,,,,"generated_by='OpenQuake engine 3.15.0', start_date='2022-05-14T10:44:47', checksum=2967670219, kind='rlz-001', investigation_time=1.0"
2lon,lat,0.002105~PGA,0.002105~SA(0.2),0.002105~SA(1.0)
3-123.23738,49.27479,2.651139E-03,1.120929E-02,1.218275E-02
4-123.23282,49.26162,2.603451E-03,1.105909E-02,1.208975E-02
5-123.20480,49.26786,2.605109E-03,1.106432E-02,1.209299E-02