Two types of microseisms

In general, microseisms are a nuisance. It is now quite widely agreed that microseisms are channel waves, similar in nature to the Lg and Rg waves. It is not at all unusual to observe microseisms which have traveled over distances of continental proportions. In order to determine the direction from which the microseisms come and to investigate in more detail the characteristics of microseismic disturbances, we established a tri-partite system on Mount Palomar.