GIS BASED TOOL FOR VOLCANIC HAZARD ASSESSMENT AND SUPPORT DECISION

Alexis Herault, ISIS/CESD, France

Authors: A. Herault (1); C. Del Negro (2); A. Vicari (2)

(1) ISIS/CESD (Ingénierie des Systèmes d'Information Stratégiques et Décisionnelles / Centre d'Etudes Scientifiques de Défense) - Université de Marne La Vallée - Paris XIII, France (herault@ct.ingv.it / Phone: +39-095-7165824)
(2) Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Catania, Italy,

Volcanic activity is characterized by a great variety of eruptive processes that are potentially hazardous. Among them, lava invasion from effusive vents, also located close to urban areas, has produced from considerable to vast damage to the people living and working in the area of the volcano. Potential hazard assessment for these volcanic phenomena needs to be known in terms of both probabilistic maps for the medium-long period, and forecast capability of ongoing eruptions. These studies are a key output of modern volcanology, since they may help the local authorities and the Civil Protection in minimizing the damage of volcanic eruptions also through a correct use of the land or a safe use of infrastructures.

The development of physical-mathematical models able to describe the evolution of volcanic processes is fundamental in order to understand the dynamic of volcano and to estimate its dangerousness and risk mitigation. The physical-mathematical models constitute a complementary methodology and are closely connected to the observation techniques of the volcanic system and those of laboratory and field. Finally, the researches of physical-mathematical models, precisely for their ability to define quantitative scenarios of a determined volcanic process, are crucial in the quantitative estimation of the dangerousness and therefore the volcanic risk. It is important that the model should be usable in autonomous way from local authorities and the Civil Protection, and should be integrated with the common tools already used for the territory management.

The ISIS/CESD (University of Marne La Vallée) and the TecnoLab (INGV-Ct) have developed a model for lava flow simulations based on Cellular Automatons, called MAGFLOW, fully integrated in a GIS environment.

The proposed model represents the central part of an extensive methodology for the hazard assessment, currently under investigation. Hazard assessment can be performed by simulating a number of lava flows from a set of initial data (vent position) and with different parameters (flow rate and days of eruption) of the volcanic system in a meaningful range of variation. In particular, a preliminary zonation is necessary for identifying possible emission regions with a certain probability of opening.
After that, a set of reference values for the parameters of the simulation model based on the knowledge of past eruptions is estimated. So, MAGFLOW is used to determine for each emission region the area that can be invaded by lava flows originated from sample points located in that region. Last step is to compute the probability of lava invasions to interested region, calculated on the basis of the simulated lava flows.

Once the input parameters have been set, the production of the invasion map is completely automatic. The results of this methodology on Etna volcano will be shown.