Non-Continuous Searching Programs
Volcanic surveillance is one of the three basic actions recommended by the international scientific and political community to reduce volcanic risk in any active volcanic area. This recommendation is made through the IAVCEI and UNESCO following the Decade for the Reduction of Natural Disasters (1990-99) declared by the UN in 1989. The purpose of volcanic monitoring is to improve and optimize the systematics for the detection of Early warning signs about a process of reactivation of the volcanic system. This early detection turns out to be of great importance for the Civil Protection systems, which are the final users of the results that derive from the surveillance and the only ones responsible for declaring the level of volcanic alert before the citizens and executing the emergency plan on the volcanic phenomenon.
Any volcanic monitoring program should have a multidisciplinary approach that takes into account the monitoring of geophysical parameters (mainly seismicity and temperature), geodetic (deformation of the terrain) and geochemical (volcanic gases). This approach includes not only the operation and maintenance of permanent instrumental networks that allow us to register in a continuous mode parameters potentially precursor of the volcanic activity, but also includes the realization of a wide monitoring and measurement in discrete (not continuous) mode of other additional variables that are also potential premonitory signs of the volcanic phenomenon and that can not be registered in continuous mode due to different technical reasons. These two forms of monitoring are not only necessary, but also complementary.