# Uniform Hazard Spectra calculator

A Uniform Hazard Spectrum (UHS) is defined as a set of spectral acceleration amplitudes, for a given number of periods, corresponding to a given probability of exceedence.

The UHS calculators allows to compute UHS for a set of sites of interest.

The implementation of the UHS calculator requires the definition of a new CALCULATION_MODE = UHS

Given a region or a set of site where to compute UHS, the following new parameter must be defined:

PERIODS_FOR_UHS = list of periods, in ascending order, to be used for spectra calculations.

POES_FOR_UHS = list of probabilities of exceedence values to be used for spectra calculations.

The input for the UHS calculator is represented by a source model logic tree and a gmpe logic tree (represented by the keys SOURCE_

The parameters needed to compute the earthquake rupture forecast from a source model and to set the GMPE parameters must be also defined:

MINIMUM_MAGNITUDE

INVESTIGATION_TIME

MAXIMUM_DISTANCE

WIDTH_OF_MFD_BIN

COMPONENT

INTENSITY_

GMPE_TRUNCATION

TRUNCATION_LEVEL

STANDARD_

REFERENCE_

REFERENCE_

SADIGH_SITE_TYPE

INCLUDE_

TREAT_AREA_

AREA_SOURCE_

AREA_SOURCE_

INCLUDE_

TREAT_GRID_

GRID_SOURCE_

INCLUDE_

FAULT_RUPTURE_

FAULT_SURFACE_

FAULT_MAGNITUDE

FAULT_MAGNITUDE

RUPTURE_

RUPTURE_

INCLUDE_

SUBDUCTION_

SUBDUCTION_

SUBDUCTION_

SUBDUCTION_

SUBDUCTION_

SUBDUCTION_

A prototype of the UHS calculator has been implemented and can be found here: https:/

A test class checking the scientific validity of the calculator is here:

https:/

For each site of interest a UHS for each probability of exceedence set by the user must be calculated. Moreover, a UHS is calculated for each logic tree sample.

Aggregated results must be also produced. From the set of results produced by the logic tree sampling, the mean UHS must be computed and also the UHS corresponding to quantile levels.

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Notes from Lars Butler:

For POES_FOR_UHS, we could simply use the general POES parameter (which was a changed made at the beginning of the Disaggregation calculator work).

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## Blueprint information

- Status:
- Started

- Approver:
- John Tarter

- Priority:
- High

- Drafter:
- None

- Direction:
- Approved

- Assignee:
- Lars Butler

- Definition:
- Approved

- Series goal:
- None

- Implementation:
- Started

- Milestone target:
- 0.6.0

- Started by
- John Tarter

- Completed by

### Related branches

### Related bugs

### Sprints

### Whiteboard

This blueprint needs to be completed in time for the Share calculations scheduled for the end of March 2012. It is expected to take approximately 1 full Sprint, to complete the tasks.