Volcano deformation monitoring using geodetic method: optimal network design

Abstract

Until nowadays there is no analytical equation that exactly state number of observing stations that should be installed and how the stations should be spatially distributed in the GNSS geodetic survey for volcano deformation studies. Due to the uniqueness of the deformation pattern of any volcano, which need sensitive monitoring network to detect small changes, the network design depends strongly on the uniqueness underlying physical phenomena. In this research, the geodetic network is designed based on physical equations to find the source including a simple spherical source of Mogi model and 3D-dislocation equation of Okada model for dykes and sills. In principle, those physical equations are used to represent the volcano deformation phenomena from surface horizontal and vertical displacement measurement. Furthermore, those physical equations are used for a reference design and realization of monitoring network. Our calculation applied at Agung and Batur volcanoes show that minimum number of observing stations depends on the total number of parameters, the combination of source shape assumption and field situation and need different type of densification in the next future measurement.