Spatiotemporal gravity changes on volcanoes: Assessing the importance of topography

Mass redistribution and deformation cause spatio-temporal gravity changes in active volcano areas. The ability of the gravity measurements to detect subsurface magma movement as a precursor to volcanic eruptions is greatly enhanced if gravity changes are analyzed and modeled jointly with ground deformation data. One effective tool for this analysis is provided by the gravity and elevation change ratio. The proposed numerical formulation allows to simulate a wide range of pressures and mass loads. However, the assessment of gravity changes is especially important when they occur without measurable ground deformation. In such a case it is very difficult to relate the gravity/uplift ratio to changes in subsurface mass movements by using classical models. In this work, we study the role played by pressure and mass sources in the interpretation of observed gravity/uplift ratio when deformation is negligible in volcanic areas associated with rough topographic relief. Citation: Charco, M., A. G. Camacho, K. F. Tiampo, and J. Fernandez (2009), Spatiotemporal gravity changes on volcanoes: Assessing the importance of topography, Geophys. Res. Lett., 36, L08306, doi:10.1029/2009GL037160.