We present the results of numerical simulation for impacts of relatively small asteroids and ice bodies of 30–100 m in size, decelerated in the atmosphere and exploding before they reach the surface, but still producing seismic effects due to the impact wave reaching the surface. The calculated magnitudes fall within the range of 4 to 6, and average seismic efficiency of these events is 2.5 × 10^–5. The results obtained allow the seismic hazard from impacts of cosmic bodies to be estimated.