Electronic Distance Measurements (EDM) on active Sicilian Volcanoes (1975-2009).

File descriptions: This dataset includes ca. 8000 Electronic Distance Measurements (EDM) collected from 1974 to 2009 on several networks installed on Sicilian Volcanoes (Vulcano, Stromboli, Etna and Pantelleria).
EDM represent one of the first methods to detect ground deformation on volcanoes having been used since 1964 on Kilauea (Hawaii). It is a precise technique that uses a laser to measure the transit time of light between a base station to the reflecting prisms positioned around the volcano; the repetition of these measurements in time allows one to monitor the slope distance variations.
EDM is a powerful tool for volcano monitoring that has been useful to define the features of magmatic and hydrothermal sources as their volume, position, geometry, and dynamics. Moreover, this technique has been largely used on volcanoes in 70th to 90th years until the 2000s when it has been gradually abandoned in favor of GPS.
This dataset reports data obtained on several Sicilian volcanoes (Etna, Vulcano, Stromboli and Pantelleria) from the early ’70 to until the 2000s, in which EDM measurements have played a major role in volcanic process knowledge and that make the Sicilian volcanoes among the ones with the longest geodetic record in the World.
Database has been organized on Microsoft Excel files and each file reports the network name (the networks list is in Table1.xls).
Inside each data file (in “database” directory), there are two sheets with a sheet reporting all measured distances and a table with associated errors. The position of each benchmark is reported on specific coordinate network files in “benchmarks coordinates” directory). All the coordinates have been obtained with GPS technique, except for the Ionica network where they have been derived from paper maps and therefore suffer by a bigger approximation.
In the data files, rows show the measurement date, the instrument model and recorded values; in the first column, the pairs of benchmarks considered are reported.
The networks Etna S and Etna NE have additional files, reporting the most frequent measurements taken during the eruptive crises of July 2001 (onset of 2001 eruption) and of October 2002 (onset of the 2002-03 eruption).
Almost all networks were measured using both the AGA6BL and the AGA 6000 Geodimeters. In the files, the survey in which the transition from one instrument to the other took place is highlighted. In those surveys, measurements were performed with both instruments in order to maintain the time-series continuity. Furthermore, in the tables “double” measurements related also to reflectors changes or new benchmarks have been highlighted.