Activities - Volcanic risk
The Department, either alone or together with other organizations in the National Civil Protection System, is engaged with the work of predicting, preventing and mitigating volcanic risk in the Italian territory, adopting appropriate measures to reduce loss of human lives and property in the event of eruptions, it is likewise engaged with handling and resolving emergencies.
Among the risks of civil protection, the volcanic one is often considered a "predictable" risk because it is believed that the phenomena that predict the rise of magma to the surface can be recognized and measured, for this reason called "precursors" (earthquakes, soil fractures, deformation of the volcanic building, changes in the emission of gases and fluid temperatures, etc..). However, this simplification does not take into account the complexity and extreme variability of volcanic phenomena and the difficulty in assessing and interpreting them.
In fact, it is more appropriate to consider the precursor phenomena only as indicators of an ongoing process that, if properly studied, analyzed and monitored, can give an idea of the state of activity of the volcano and its possible evolutions, allowing to identify any anomalies. For this reason, some of these parameters are measured through networks of stations installed on active volcanoes and observed with different methods, for example, by satellite or by flying over or, more simply, by direct inspections in the field.
However, even if these phenomena are studied and monitored on time, it is not possible to predict with certainty, even for the peculiarities that characterize each volcano, when and how a volcanic eruption will occur. In the current state of knowledge, in fact, no form of deterministic prediction can be hypothesized.
However, some important information regarding the behaviour of a volcano can be drawn from an accurate and in-depth analysis of its eruptive history. In this sense, it is possible to make hazard assessments in probabilistic terms, to understand what "type" of eruption will occur, the possible scenarios and areas that will eventually be affected by the effects of volcanic activity. These assessments are the basis for identifying the reference scenario of a future eruption and the perimeter of areas potentially subject to dangerous phenomena, used in emergency planning (e.g. red zone and yellow zone of Vesuvius and Phlegraean Fields).
However, it should be noted that forecasts of a probabilistic nature are not always possible and not for every type of phenomenon. Moreover, these forecasts are strongly conditioned by the availability of adequate and numerous historical series of observations that can be linked to the actual occurrence of events. Probabilistic applications are possible only for some phenomenologies that characterize the active volcanoes in a permanent form, for example Etna and Stromboli, for which, systems aimed at the "early" detection, in their initial phase, of explosive events of high intensity are being tested.
To sum up, the evaluation of the state of activity of a volcano and its possible evolution consists in a complex process based on:
- precise and constant monitoring of the physical and chemical parameters and of the characteristic phenomenologies of the volcano;
- early detection and immediate communication of parameter anomalies or significant events indicating an ongoing process;
- analysis of the current situation, in comparison with the eruptive history, also through the consultation of experts within the scientific community of the sector.
All this information allows both local and national civil protection structures to elaborate the risk assessments of competence and to activate the possible measures of alert and operational response.
The subject institutionally responsible for the monitoring and surveillance of Italian volcanoes is the INGV-National Institute of Geophysics and Volcanology. In particular, the volcanoes of the Campania area are monitored by the Vesuvius Observatory at the Ingv section of Naples. The volcanoes of the Sicilian area are monitored by the INGV Section of Catania-Osservatorio Etneo. Other sections of the INGV (e.g. Palermo) as well as universities and other research institutes also contribute to the monitoring of volcanic activity parameters.
The National Commission for the Forecasting and Prevention of Major Hazards, the highest scientific advisory body of the Civil Protection Department, supports the risk assessments carried out by the National Civil Protection Service through its own section dedicated to volcanic risk, composed of some of the leading volcanological experts at the national level.
To allow the elaboration of emergency plans for volcanoes active in Italy, in line with what is also expected at the international level, specific "alert levels" have been identified for Vesuvius, Phlegraean Fields, Etna, Stromboli and the island of Vulcano, describing the state of activity of each volcano, indicating whether it is in a condition of balance or imbalance. For these five volcanoes, the alert levels are already used while those for the volcano Ischia are being developed.
The alert levels are identified on the basis of the combination of monitoring parameters and data on any events in progress. They are represented by four colors - green, yellow, orange and red - which are indicative of the possible evolution of the state of activity of the volcano towards scenarios of event "of national importance" that require to be faced with extraordinary means and powers, through the coordinated intervention of a plurality of subjects (art.2, paragraph 1 letter c of Law 225/92). This is the case of volcanoes such as Vesuvius and Campi Flegrei.
Etna, Stromboli and the island of Vulcano, on the other hand, are characterized by a type of volcanic activity that can also involve events of local impact that do not necessarily evolve towards scenarios of national importance. For this reason, for these volcanoes have been identified, even scenarios related to scale phenomena, intensity and impact such as to determine emergency situations at the local level, which can be addressed by the competent subjects in the ordinary way (Region and municipalities).
The alert levels are declared by the Civil Protection Department, in close collaboration with the respective regional civil protection structures, after hearing the opinion of the Major Risks Commission - Volcanic Risk Sector, if the times and methods of evolution of volcanic phenomena allow it. The evaluation is based on the reports of the phenomenologies and on the evaluations of dangerousness made available by the Ingv-National Institute of Geophysics and Volcanology and by the other Centres of Competence, with particular regard, for the Sicilian volcanoes, to the Department of Earth Sciences of the University of Florence.
For each volcano, the transition from one alert level to the other may occur in advance of the occurrence of the phenomena, if the information provided by the Competence Centers allow it. If this is not the case, the passage can be decreed as an observed phenomenon, therefore it has taken place or is in progress. In this regard, it is useful to underline that the crossing of the alert level may not necessarily take place in a sequential or gradual way, as sudden or sudden changes in volcanic activity are always possible, even if they are completely unforeseen.
It should be noted that some phenomena are completely unpredictable and sudden - such as the violent explosive activity at Etna and Stromboli or the explosive phreatic activity and gas exhalation on the island of Vulcano - so even when the alert level is "green" the risk for these volcanoes is never absent. When these events occur, the alert level is not necessarily changed, since it determines a condition of "local emergency" that requires the activation of the operational response of the territorial structures of civil protection.
Emergency planning plays a key role in prevention activities. For volcanic risk this activity is carried out, often, at the national level in light of the expected phenomena and the high exposure of the territory that may be involved. Italian volcanoes clearly have different characteristics, with different types of effects and risks, and national and territorial emergency plans are based on reference scenarios and alert levels specific to each volcano.
Emergency planning for volcanic risk is based on one or more reference scenarios, able to describe the expected phenomena and to identify the exposed territory taking into account the state of the volcano, on the basis of its eruptive history. This activity is carried out with the help of physical-mathematical simulation models that allow to better calibrate the hypotheses regarding the effects of the phenomena on the territory. The Department promotes research projects in the field of volcanology for the identification of these scenarios, and to deepen the knowledge on volcanic risk and thus improving the methodologies and actions of civil protection.
National planning is drawn up for scenarios with a significant impact on the territory, which require the intervention of the National Service of Civil Protection, able to identify the most appropriate strategy of intervention to implement in case of emergency (such as displacement of the population from risk areas, partnerships, safeguard measures and assistance). With regard to the least impact phenomena, the local authorities, together with the Department, have to identify the operational measures to adopt in the emergency planning.
On the basis of the volcanoes monitoring activity, the scientific community assesses the "state of the volcano" and also the possible evolution of the phenomena even in the short-term. As such, emergency planning is based on alert levels, which represent, for each active Italian volcano, a schematization of the volcanic activity, by expressing a condition of equilibrium/disequilibrium of the volcanic system through four colors: green, yellow, orange and red, based on the phenomenology and the risk assessments made available by the competence centers.
Using the alert levels as a starting point, but also on the basis of other operational assessments , the planning envisages the activation of operational phases in order to ensure a coordinated response of different actors for the achievement of specific and sector-specific objectives.
At the different territorial levels, civil protection exercises are organized to test the operational procedures provided in the planning and inform the population, but also specific education or information activities for operators and the population such as educational meetings, aimed at enhancing risk knowledge and awareness, emergency plans and rules of conduct to observe in case of crisis.
Emergency planning should also be included in territorial planning so as to reduce risk exposure by avoiding new constructions in specific areas, and by developing urban planning regulations that may reduce the vulnerability of constructions, not only for seismic risk, but also for some volcanic phenomena of lesser impact (e.g. falling and accumulation of ashes).