Periodic changes in the earth surface topography caused by the gravitational attraction of the moon and sun, measured with tiltmeters. Used in studies of volcanic activity.
Article in the May 28, 1998 issue of Volcano Watch describing of correlation of earth tides to volcanic eruptions and value in monitoring underground magma movement with deformation measurement instruments including tiltmeters and strainmeters.
U.S. Department of the Interior |
U.S. Geological Survey