ALBERT

Description: Glass stability (GS) indicates the glass reluctance or ability to crystallise upon heating and it can be characterised by several methods and parameters. GS is frequently used to retrieve glass-forming ability (GFA) of corresponding liquids: the likelihood of obtaining a crystal-free glass through melt-quenching. In the present study, GS has been determined for the first time on six sub-alkaline glasses having complex (natural) compositions, the most widespread and abundant on Earth. The two end-members are a basalt and a rhyolite, B100 and R100, plus intermediate compounds B80R20, B60R40, B40R60, B20R80. Each glass was heated in a differential scanning calorimetry (DSC) at a rate of 10 °C/min (600 °C/h) to measure in-situ Tg (glass transition), Tx (onset of crystallization) and Tm (melting) temperatures, from ambient to their liquidus temperatures. The ex-situ run-products quenched at Tm have been characterised by scanning electron microscope (SEM) and electron probe micro-analyzer (EPMA) techniques, in order to quantify textures and compositions of phases, respectively. R100 and B20R80 do not shown any DSC peaks, whereas B40R60, B60R40, B80R20 and B100 thermograms display progressively more resolvable peaks. As SiO2 (wt%) in the melt increases from B100 to B40R60, Tx linearly increases, Tm first decreases and then levels off, whereas Tg weakly changes. R100 and B20R80 run-products are completely glassy, while from B100 to B40R60 the amount of glass (gl) increases from 48.5 to 97 area%, counterbalanced by a decrease of clinopyroxene (cpx) content from 47.7 to 16 area%. The spinel (sp) content is constrained within a narrow range of 0.9–3.8 area%. Conversely, plagioclase (plg) crystallizes heterogeneously on the Al2O3 holders only in B100 and B80R20 and at distance 〈 100 μm from it. R100, B20R80, B40R60 and B60R40 ex-situ glasses exhibit chemistries very close to their starting compositions, according to the absence (or scarcity) of crystals formed during heating. Instead, B100 and B80R20 glasses are enriched in Si, Al, and Na but depleted in Fe, Mg, and Ca due to internal crystallization of sp and mostly cpx. Specifically, the composition of cpx from B100 is enriched in M2Ca, M1Mg, M2,M1Fe, and M1,TAl. The values of KT, KH, KW, KLL, and w2 (as GS parameters) increase linearly and monotonically as a function of SiO2, showing high correlation coefficients (R2 = 0.93–0.95). Moreover, Tx values and GS parameters highly correlate with GFA via Rc (critical cooling rate), as previously determined by ex-situ cooling-induced experiments. This leads to the conclusion that GS scales with GFA for natural silicate compositions. In addition, the in-situ Rc value of B100 measured with DSC is 〉 45 °C/min (〉 2700 °C/h), corroborating the value of Rc of ~ 150 °C/min (9000 °C/h) determined by ex-situ experiments. In turn, relevant solidification parameters on heating or cooling obtained by DSC investigations, also for chemically complex (natural) systems, extend the results from previous observations conducted on simple silicate systems. These outcomes are relevant for lavas or magmas that re-heat glass-bearing volcanic rocks, as well as for fabricating glass-ceramic materials with desirable texture and composition of phases starting from abundant and very cheap raw volcanic rocks.

Description: Published

Description: 21-30

Description: 3V. Proprietà dei magmi e dei prodotti vulcanici

Description: JCR Journal

Description: A volcanic risk perception study of the population residing near Vesuvius was carried out between May and July, 2006. A total of 3600 questionnaires with 45 items were distributed to students, their parents and the general population. The largest number of surveys (2812) were distributed in the 18 towns of the Red Zone, the area nearest to the volcano that is exposed to pyroclastic flow hazards and whose 550,000 residents, according to the civil protection emergency plan (in operation since 1995), should be evacuated in case of an eruption crisis. The remaining 788 questionnaires were distributed in 3 additional towns and 3 neighborhoods of Naples, all within the Yellow Zone, which is an area exposed to pyroclastic fallout hazards. A total of 2655 surveys were returned, resulting in a response rate of 73.7%. Results indicated that people have a realistic view of the risk: they think that an eruption is likely, that it will have serious consequences for their towns and for themselves and their families and they are quite worried about the threat. However, several other social, economic, and security-related issues were listed as a problem more often than Vesuvius. The study also demonstrated a widespread lack of knowledge about the emergency plan, a lack of confidence in the plan's success and in public officials and low feelings of self-efficacy. People want to be more deeply involved in public discussions with scientists and civil protection officials on emergency planning and individual preparedness measures. It is clear from the results that a major education-information effort is still needed to improve the public's knowledge, confidence and self-efficacy, thereby improving their collective and individual capability to positively face a future volcanic emergency.

Description: Published

Description: 244–258

Description: 4.3. TTC - Scenari di pericolosità vulcanica

Description: JCR Journal

Description: reserved

Description: In risk mitigation strategies, communication and information have an important role, in particular during long lasting periods of volcanic inactivity. Many studies have shown that information will often be ignored or resisted, even during a volcanic crisis, if not placed into an appropriate social and cultural framework. In particular some researches focused on the public's understanding and perception of volcanic hazards and risks during volcanic crises or quiescence periods have highlighted on one side how important education and outreach programs are, and on the other the needing they were based on a real knowledge of the needs of the at-risk population. Our studies aim has been to evaluates the level of knowledge of hazard and risk related issues, the level of education and preparedness of residents, and the relationship of these factors to residents' sense of community. The researches, carried out in the last years, have investigated volcanic hazard and risk perception in population living ,close to Etna, Vesuvio and Campi Flegrei caldera, in Southern Italy. Moreover local officials that gave some support to the surveys declared their interest in surveys’ results, that could be useful to design more effective strategies in educating and motivating the public to take more in account the natural peculiarities of their territory, and the related volcanic hazards and risks.

Description: Published

Description: Tenerife, Canary Islands, Spain

Description: 5.9. Formazione e informazione

Description: open

Description: While a considerable body of work concerning citizens’ perceptions of risk for volcanic hazards has been done in the United States and New Zealand, no comparable study has focused on residents near Italy’s two major volcanoes: Vesuvio and Etna. This survey study, involving 174 participants, focused on various measures of risk perception, feelings of personal vulnerability to the volcanic threat, and confidence in government officials’ preparedness for potential eruptions. Although it was expected that due to a recent eruption of Etna, residents there would have higher levels of perceived risk than those at Vesuvio, findings mostly demonstrated the reverse. Additionally, residents living in the highest risk areas at Vesuvio demonstrated low levels of awareness concerning evacuation plans and low levels of confidence in the success of such plans.

Description: Published

Description: 159-165

Description: N/A or not JCR

Description: restricted

Description: There is a considerable body of work concerning citizens’ perceptions of risk regarding volcanic hazards, with most studies conducted in the United States and New Zealand, No comparable study has been done in Italy, where millions of residents live in close proximity to Mt. Etna and Mt. Vesuvio. This study compared the survey responses of 516 participants at Etna and Vesuvio on topics such as salience of the volcanic hazard, various measures of risk perception, perceived control over eruption effects, perceived preparedness, confidence in government officials’ efforts to protect them from the eruption hazard, self efficacy and sense of community. While residents at Etna appeared to have an objective and informed perspective concerning the volcanic hazard, those residents living in the highest risk areas at Vesuvio demonstrated high levels of fear and perceived risk concerning an eruption, but low levels of perceived ability to protect themselves from the effects of an eruption. These Vesuvio residents also demonstrated low levels of awareness concerning evacuation plans, and low levels of confidence in the success of such plans.

Description: Published

Description: N/A or not JCR

Description: restricted

Description: The Campi Flegrei which includes part of the city of Naples, is an active volcanic system; its last eruption occurred in 1538 AD. More recently two significant crises occurred between 1969 and 72 and 1982–84 and were accompanied by ground movements (bradyseism) and seismic activity, forcing people of the town of Pozzuoli to be evacuated. Since 1984 development of a volcanic emergency plan has been underway. In 2000 Civil Protection published a risk map which defined the Red Zone, an area highly at risk from pyroclastic flows, which would need to be evacuated before an eruption. The first study to evaluate the volcanic risk perceptions of the people living within the Campi Flegrei area was completed in spring 2006, resulting in the largest sample ever studied on this topic except for one on Vesuvio area residents by Barberi et al. (2008). A 46 item questionnaire was distributed to 2000 of the approximately 300,000 residents of the Campi Flegrei Red Zone, which includes three towns and four neighborhoods within the city of Naples. A total of 1161 questionnaires were returned, for an overall response rate of 58%. Surveys were distributed to junior high and high school students, as well as to adult members of the general population. Results indicated that unlike issues such as crime, traffic, trash, and unemployment, volcanic hazards are not spontaneously mentioned as a major problem facing their community. However, when asked specific questions about volcanic risks, respondents believe that an eruption is likely and could have serious consequences for themselves and their communities and they are quite worried about the threat. Considering the events of 1969–72 and 1982–84, it was not surprising that respondents indicated earthquakes and ground deformations as more serious threats than eruptive phenomena. Of significant importance is that only 17% of the sample knows about the existence of the Emergency Plan, announced in 2001, and 65% said that they have not received enough information about the possible effects of an eruption. In addition, residents' sense of community was significantly positively correlated with both confidence in local authorities and Civil Protection as well as residents' feelings of self efficacy regarding their ability to protect themselves from a potential eruption. These results indicate that most residents of Campi Flegrei, while aware of the volcanic threat posed by Vesuvio, are not familiar with more local volcanic hazards in their area. This, coupled with little knowledge about the Emergency Plan and the very low level of information residents have about the effects of a possible eruption, suggests that authorities, in collaboration with the scientific community, should direct their efforts to better educate and inform the population about volcanic hazards and the Emergency Plan, and that such efforts could be facilitated by trying to encourage stronger community bonds.

Description: Published

Description: 118-130

Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani

Description: JCR Journal

Description: restricted