Determining the source characteristics of explosions near the Earth's surface

We present a method to determine source characteristics of explosions near the Earth's surface. The technique accounts for the reduction in amplitudes as the explosion depth approaches the free surface and less energy is coupled into the ground. We apply the method to the Humming Roadrunner series of shallow explosions in New Mexico where the yields and depths are known. Knowledge of the material properties is needed for both source coupling/excitation and the free surface effect. Although there is the expected trade‐off between depth and yield, the estimated yields are close to the known values when the depth is constrained to the free surface. We then apply the method to a regionally recorded explosion in Syria. We estimate an explosive yield less than the 60 t claimed by sources in the open press. The modifications to the method allow us to apply the technique to new classes of events. Key Points Method allows us to determine the yield and depth/height of shallow explosions Tested on explosions in New Mexico where the source characteristics are known Applied to a large explosion in Syria recorded at stations in Turkey