Higher modes of seismic surface waves: Second Rayleigh mode energy

The energy of the second Rayleigh mode is determined for earthquakes with continental paths to Uppsala. The energies have a large scatter because different source orientations and different focal depths alter the amount of second Rayleigh mode energy excited, and the radiation patterns alter the amount of energy propagating along different azimuths from the source. If the scatter is averaged, there is an indication of the rate of increase of energy with increasing magnitude, and the variation of energy with focal depth can be interpreted in terms of the variation with depth of the particle amplitude of the second Rayleigh mode. The atmospheric nuclear explosions over Novaya Zemlya excited large-energy second Rayleigh modes.