THE VARIATIONS OF THE GRAVITY AND TILT LOADING TIDE IN SEISMOGENIC PROCESS

The elastic parameter variations within seismic source region prior to an earthquake result in variations of the seismic wave velocity. In this paper, on the basis of the phenomenon of wave velocity anomaly, before an earthquake of M = 7, the distortion of the Earth's gravity and tilt by the M2 loading tide at some places near the coastline of China have been estimated by means of the results of the loading tide studies. We showed that the distortion of the gravity is very little and that of the tilt is observable. It is suggested that tilt observations should be done in the seismic active areas adjacent to the sea.