Determination of tiny changes in the slope angle or tilt of the ground in order to monitor deformation caused by moving magma. Instruments detect variations in a liquid level or in the position of a pendulum.
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.
Overview of the Long Valley Caldera with links to monitoring data including earthquakes and deformations, long-term outlook, volcano hazards in the area, USGS response plan, image gallery, monitoring and topical studies, publications and references.
U.S. Department of the Interior |
U.S. Geological Survey