Masking and Discrimination

A fundamental objective of the S-6 (physical basis for discrimination) sub-task of the CTBT R&D Seismic Monitoring Program at Los Alamos is to analyze the sensitivity of the regional signal to source configuration, material properties, geologic layering and structure, along with complications along the path of the signal. Our approach is to combine the results of conventional analysis of field data from explosions and earthquakes with results of numerical models of actual and idealized situations. Existing first-principles, finite difference codes allow us to examine source effects in the non-linear regime; linking the results of these near-source calculations to finite difference, anelastic wave propagation codes allows us to examine the effect of various source region and propagation path characteristics on signals observed at regional distances. An investigation of discriminant differences for the DIVIDER and CORREO underground nuclear explosions is provided as an example of the approach used. Work sponsored by DOE-project number ST482