Abstract
During I. G. Y. period the routine and tripartite observations of microseisms were made at Abuyama Seismological Observatory. And after I. G. Y. the particle motions of the ground were observed by the vector seismographs in UD-NS, UD-EW and EW-NS components.
These observations show that microseisms are generated by sea waves propagated from the disturbance source to the near coast of the Observatory. And it was made clear that amplitudes and periods of microseisms depend on the scale of the disturbance source and the distance from the disturbance source to the coast.
As the velocity of the microseismic wave 2.4-2.6km/sec. is reliable.
From the earth-particle trajectories it was confirmed that microseismic waves are Rayleigh-type, and that Love waves are scarcely present.
