Question about modelling parent faults and fault sections using MultiFaultSource
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SeismicStudent
Aug 13, 2026, 7:16:06 AM (2 days ago) Aug 13
to OpenQuake Users
Dear OQ Users,
I am preparing a fault-source model for a classical PSHA calculation and would appreciate your advice on whether the attached OpenQuake input files appropriately represent the intended fault system.
In this study, I plan to consider three parent faults as three fault sources. Each parent fault consists of approximately five mapped fault sections, resulting in approximately fifteen sections in total.
For each parent fault, I intend to consider rupture scenarios involving either a single section or multiple adjacent sections. Ruptures extending across different parent faults are not considered at this stage. For a parent fault consisting of five sections, all contiguous rupture combinations are included, from individual section ruptures to rupture of the entire parent fault. This results in up to fifteen rupture scenarios for each parent fault and approximately forty-five rupture scenarios for the three parent faults.
Because fault occurrence-rate information is currently unavailable, I plan to assume a total annual occurrence rate for each parent fault. The parent-fault rate will then be distributed among its permitted rupture scenarios so that the sum of the individual rupture rates is equal to the assumed total rate of the corresponding parent fault. Alternative rate distributions may subsequently be considered as part of a sensitivity analysis.
The attached input files were prepared using the following interpretation:
each parent fault is represented as one multiFaultSource;
the mapped fault segments are represented as sections belonging to the corresponding parent fault;
single- and multi-section rupture scenarios are defined within each parent fault; and
each rupture scenario is assigned its own magnitude and occurrence probabilities.
The geometry, magnitudes, and occurrence rates in the attached files are provisional. At this stage, my primary objective is to confirm whether the source-model structure and the interpretation of parent faults, fault sections, and rupture combinations are appropriate before applying the actual fault data.
I am preparing a fault-source model for a classical PSHA calculation and would appreciate your advice on whether the attached OpenQuake input files appropriately represent the intended fault system.
In this study, I plan to consider three parent faults as three fault sources. Each parent fault consists of approximately five mapped fault sections, resulting in approximately fifteen sections in total.
For each parent fault, I intend to consider rupture scenarios involving either a single section or multiple adjacent sections. Ruptures extending across different parent faults are not considered at this stage. For a parent fault consisting of five sections, all contiguous rupture combinations are included, from individual section ruptures to rupture of the entire parent fault. This results in up to fifteen rupture scenarios for each parent fault and approximately forty-five rupture scenarios for the three parent faults.
Because fault occurrence-rate information is currently unavailable, I plan to assume a total annual occurrence rate for each parent fault. The parent-fault rate will then be distributed among its permitted rupture scenarios so that the sum of the individual rupture rates is equal to the assumed total rate of the corresponding parent fault. Alternative rate distributions may subsequently be considered as part of a sensitivity analysis.
The attached input files were prepared using the following interpretation:
each parent fault is represented as one multiFaultSource;
the mapped fault segments are represented as sections belonging to the corresponding parent fault;
single- and multi-section rupture scenarios are defined within each parent fault; and
each rupture scenario is assigned its own magnitude and occurrence probabilities.
The geometry, magnitudes, and occurrence rates in the attached files are provisional. At this stage, my primary objective is to confirm whether the source-model structure and the interpretation of parent faults, fault sections, and rupture combinations are appropriate before applying the actual fault data.
I would greatly appreciate any comments or recommendations.
Best regards,
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