Not getting stdev in scenario risk agg loss

[Tiegan Hobbs]

Hi there,

I am using OQ 3.20 for scenario risk calculations and wanting to be able to comment on the uncertainty. When I export the aggregate asset losses output it only provides mean results, not the stdev. Here's an example .ini:

[general]
description = Montreal M5-7.5 events, based on the 1732 event at 45,5 N, 73,6 W. Hypocentral depth of 10km (GSC). Using representative azimuth of St Lawrence Valley, based on Lamontagne et al., (2000, EOS), to represent Iapetan Rift. Specifically, str/dip/rake of 040/75/90 from Tremblay et al., (2003, Tectonophysics).
calculation_mode = scenario_risk
random_seed = 113

[Exposure model]
exposure_file = ../../openquake-inputs/exposure/general-building-stock/oqBldgExp_CE.xml

[site_params]
site_model_file = ../../openquake-inputs/earthquake/sites/regions/site-vgrid_CA.csv

[Rupture information]
rupture_model_file = ../ruptures/rupture_SCM5p8_MontrealIapetan.xml
rupture_mesh_spacing = 4

[Calculation parameters]
gsim_logic_tree_file = ../../CanadaSHM6/OpenQuake_model_files/gmms/LogicTree/OQ_classes_NGASa0p3weights_stablecrust.xml
truncation_level = 3.0
maximum_distance = 600
number_of_ground_motion_fields = 200

[Vulnerability]
taxonomy_mapping_csv = ../../openquake-inputs/earthquake/vulnerability/CanSRM1_TaxMap_b0.csv
structural_vulnerability_file = ../../openquake-inputs/earthquake/vulnerability/vulnerability_structural_CAN.xml
nonstructural_vulnerability_file = ../../openquake-inputs/earthquake/vulnerability/vulnerability_nonstructural_CAN.xml
contents_vulnerability_file = ../../openquake-inputs/earthquake/vulnerability/vulnerability_contents_CAN.xml
occupants_vulnerability_file = ../../openquake-inputs/earthquake/vulnerability/vulnerability_occupants_CAN.xml

I'm also curious if there's a standard approach to extract percentiles from scenario risk results, presumably using the agg event losses. I assume you would just rank the agg event losses and select the entry marking the top and bottom X%?

Thanks for your help!

Cheers,

Tiegan

[Anirudh Rao]

Hi Tiegan,

The option to compute quantiles was recently added to the scenario_risk calculator: https://github.com/gem/oq-engine/pull/10320. Starting from engine v3.24 onwards, you should be able to compute risk quantiles for scenarios by including a line quantiles = 0.05 0.50 0.85 (eg.) in your job file and the requested quantiles should be available in the output "Aggregate Risk Statistics". There seems to be a corner case where this output is not visible to the user if the calculation involves a single ground motion model (which we are investigating), but since your job file is using a gsim_logic_tree_file, hopefully this shouldn't affect your calculation. 

The standard deviation is not computed, but can be computed externally using the Aggregated Risk By Event output.

Cheers,

Anirudh