Sensitivity test of the geodetic network in Las Canadas Caldera, Tenerife,for volcano monitoring

A 17-benchmark geodetic network in the volcanic area of the Teide Caldera, Canary Islands has been utilised several times: since 1982 to detect crusta l movements associated with volcanic activity within the network as well as a procedure for solving configuration problems. The network is located on the mid-western side of the Caldera, where there are two different morpholo gical zones that both have benchmarks. The authors performed a sensitivity test of this geodetic network for volcano monitoring purposes. To do so, we use a deformation model to calculate surface displacement caused by a dike intrusion in a homogenous half space. The depth and location of dike are c hanged to study the variation of the effects produced (displacements). The size and location of the intruded dike are found to play a major role in de termining both the displacement pattern and magnitude. When the dike is clo se to the surface, there is an inversion of the surface displacement patter n and very large surface displacement at certain benchmarks. Such phenomena can serve as precursors of such dike eruptions. Our study show a clear nee d to extend the existing geodetic network to cover the full island for volc ano monitoring purposes. (C) 2000 Elsevier Science B.V. All rights reserved .