CSEP 1 STEPCoulombQuickFix
Introduction
RFC002 discusses the issues observed with the STEPCoulomb model in the CSEP New Zealand testing center. CSEP provides a computational infrastructure to perform and evaluate both prospective and retrospective earthquake forecasting experiments. In regards to a retrospective forecasting experiment, it was observed that the STEPCoulomb model installed in CSEP did not produce the expected output for the Darfield Experiment -- a forecasting experiment of the 2010 Christchurch Earthquake sequence.
The STEPCoulomb model represents a hybrid model consisting of a statistical STEP model and a physics-based Coulomb stress model. The executable that computes the STEP forecast obtains a Coulomb mask based on available slip models, and uses the information contained from the Coulomb stress model to provide physical constraints to the statistical STEP (short-term earthquake prediction) forecast. The STEPCoulomb forecast should produce two forecast outputs: (1) STEP forecast, and (2) STEPCoulomb forecast, which can be compared to determine the pairwise efficacy of the two forecasting models.
This document is laid out as follows: Problem Statement provides a description of the problems as communicated by the science groups to SCEC IT; and Proposed Solution provides an explanation of the proposed solution to the problem outlined in the problem statement.
Problem Statement
It was suspected the STEPCoulomb forecast, computed by the New Zealand CSEP testing center, did not produce the expected outputs. This issue affects an on-going manuscript review, so an urgent response is needed. The problem was confirmed by comparing the STEP forecast with the supposed STEPCoulomb forecast and determining that there were no differences between the forecasts. Computing differences between the two forecasts indicated that both files were exactly similar. It is expected that the physics-based Coulomb stress model should influence the rates forecasted by the statistical STEP model.
Proposed Solution
[TODO]
