TIDAL STRAIN AS A POSSIBLE CAUSE OF MICROSEISMS AND ROCK JOINTING
Tidal strain of the Earth9s crust, particularly in the zone of fracture, is suggested as a significant contributing cause of microseisms. Both these phenomena are of relatively small magnitude, but they are continuous and universal. If this suggestion is judged to be reasonable and if microseisms originate chiefly at shallow depths, tidal forces may be considered also as a factor in rock jointing.