Critical Feature Defeat for Underground Facilities - Thermal Accelerant Payload

We propose to improve the calculation of seismic event locations at regional distances in areas without calibrated station corrections by replacing the conventional travel-time table with those travel times that are generated (during the locationcomputation) from an existing program that uses 3-D ray-tracing through an inhomogeneous earth model. Regional location accuracy will be improved by calculating the effects of the 3-D variations in crust and upper mantle structure and by extending thecalculations to include later-arriving regional phases. The confidence region surrounding the location will not be calculated using the conventional linear approximation but instead by forward modeling of rays cast from trial locations surrounding thecomputed one. This directly determined confidence region will likely not be elliptical, and a suite of such confidence regions will be generated by perturbations of the assumed inhomogeneous earth model to define more accurately the true uncertainty inthe location by explicitly incorporating primary and secondary phase travel-time uncertainty. This suite of confidence regions can be used to generate a single confidence region by stacking them, using weights assigned as Bayesian probabilities.Inaddition to its immediate applicability for verifying compliance with the Comprehensive Test Ban Treaty, the proposed methodology will allow the confidence regions of earthquake locations (especially regionally and locally monitored aftershocks) to bedetermined more accurately. This will allow the location of faults and the extent of seismic hazard areas to be mapped more precisely for purposes of civic planning, industrial development, and insurance risk calculation.