Geodetic monitoring of Mt. Vesuvius Volcano, Italy, based on EDM and GPS surveys

The geophysical monitoring system of Mt. Vesuvius volcano includes a geodetic EDM network having average basis lengths amounting to 6 km. This trilateration network is localised around the central crater and consists of 21 stations with a geometry allowing measurement of 60 slope distances. In order to relate this network to more stable areas and to other networks in the Apennines, the EDM net has been extended using GPS methods. In summer 1993 four GPS receivers (Leica System 200) were used on the same points measured with EDM method. During this survey two long bases from the volcano to the more stable limestone platform located in the S direction were measured. The same baselines were previously measured by using an AGA 600 laser geodimeter. In January 1995 a new survey was performed by using two infrared distantiometers (1 DISTOMAT DI3000 and an AGA 142). The comparison with the data since 1975 does not show any significant ground deformation to be ascribed to the volcanic activity. Moreover the consistency between GPS and EDM data allows to exclude systematic differences between these two methodologies for volcano monitoring.