This task is subdivided into two components that will be completed by working groups containing five experts selected from the international research team:
- Task 1A In this subtask, a consistent strategy for modeling ground motions will be defined. The issues that are addressed in this subtask are as follows: (i) consistency in the model parameters (magnitude, distance, style-of-faulting, site classification, etc.) and in the ground motion parameters (PGA, PGV, spectral acceleration, etc.); (ii) balancing the approaches to modeling ground motions (e.g. empirical versus numerical simulations). The working group will develop a consistent strategy for developing global ground motion models for active crustal regions, subduction zones and stable continental regions.
- Task 1B In this subtask, site effects in parametric ground motion models will b estimated. The parametric ground motion models all use some simplified site classification method to account for the site effects. To apply the ground motion models requires having estimates of the site classification for the entire region of interest. Therefore, an efficient method for estimating the site classification, consistent with the classification used in the ground motion models, is needed and will be completed by correlating available site classifications with other parameters that are available for the entire region. In parallel, alternative site parameters and site mapping approaches will be evaluated. Initial models for the correlations will be selected based on past studies. These models will then be ranked in terms of their use in Task 6.