A quantitative approach to the 2014 Mt. Ontake volcanic eruption news coverage: understanding the information gap and the public response to the anniversary coverage

This paper studies the news coverage of the 2014 Mt. Ontake eruption disaster from 2015 to 2019, and the public response to the fifth anniversary coverage. Information on the issues regarding the risk of low-frequency disaster events such as volcanic eruption is brought into the public largely through the media. Unless there is a volcano nearby, there are few opportunities to discuss volcanic disaster prevention, and enhance volcanic risk perception. Therefore, the media agendas on volcanic risk are an indicator of what people know about volcanic disaster preparedness. This study quantitatively analyzed the 2014 Mt. Ontake eruption reports of national, regional, and local newspapers to reveal their topic distributions. In addition, the anniversary gained intense public attention due to the large amount of media coverage. It was a significant opportunity for society to discuss volcanic risk. By observing people’s online responses to the anniversary coverage, a trend could be identified. We found a significant difference in media attention among the three newspaper types. The local newspaper covered four topics relating to volcanic risk in a well-balanced way, but the national and regional newspapers paid greater attention to one or two topics. Many online comments presented the view that a mountaineering should be done at individuals’ own risk, and volcano shelters would be ineffective for averting volcanic disasters. The anniversary coverage unintentionally contributes to stigmatizing or scapegoating a certain group, rather than promoting risk communication in the public sphere on the Web. With the onset of the information and communication information technology era, an online dialogue regarding disaster awareness and prevention is important. A volcano disaster risk communication strategy on the Web should be developed.

Volcanic Risk Mitigation that Could Have Been Derailed but Wasn’t: Pinatubo, Philippines 1991

This is the story of a successful risk mitigation effort at Mount Pinatubo in 1991 that could easily have failed. The counterfactuals are the myriad of ways that the effort could have failed but didn’t. Forecasts for a large, VEI 6 eruption were the basis of 10, 20, 30 and, during the climactic eruption, even 40 km radius evacuations. Let’s use the metaphor of a train headed for the destination of successful mitigation, but that could have easily have been derailed or slowed and shunted off to a siding. Among the possible nodes of derailment: capability and trust between responding institutions; external distractions, both natural and man-made; early alert; scientific judgment of whether, when, and how big an eruption will occur; stochastic or unpredictable factors that can make even the best scientific judgment moot; optimal balance between caution and decisive actions, by scientists and civil defense alike; and effective communication between all parties. Potential derailments are detailed at each of these nodes for Pinatubo.

Integrating hazard, exposure, vulnerability and resilience for risk and emergency management in a volcanic context: the ADVISE model

Risk assessments in volcanic contexts are complicated by the multi-hazard nature of both unrest and eruption phases, which frequently occur over a wide range of spatial and temporal scales. As an attempt to capture the multi-dimensional and dynamic nature of volcanic risk, we developed an integrAteD VolcanIc risk asSEssment (ADVISE) model that focuses on two temporal dimensions that authorities have to address in a volcanic context: short-term emergency management and long-term risk management. The output of risk assessment in the ADVISE model is expressed in terms of potential physical, functional, and systemic damage, determined by combining the available information on hazard, exposed systems and vulnerability. The ADVISE model permits qualitative, semi-quantitative and quantitative risk assessment depending on the final objective and on the available information. The proposed approach has evolved over a decade of study on the volcanic island of Vulcano (Italy), where recent signs of unrest combined with uncontrolled urban development and significant seasonal variations of exposed population result in highly dynamic volcanic risk. For the sake of illustration of all the steps of the ADVISE model, we focus here on the risk assessment of the transport system in relation to the tephra fallout associated with a long-lasting Vulcanian cycle.

A New Inclusive Volcanic Risk Ranking, Part 2: Application to Latin America

Volcanic Risk Ranking (VRR) methods have been developed worldwide as a way to hierarchize the volcanic systems and help target strategies for risk reduction. Such hierarchization is especially important in areas characterized by a large number of active volcanoes but limited resources. This is the case of Latin America, where large populations live nearby almost 300 active volcanoes. Here we assess the volcanic systems in Latin America with at least one eruption in the last 1,000 years based on the VRR strategy presented in a companion paper that accounts for the 4 main risk factors: hazard, exposure, vulnerability and resilience. Our results reveal that, among the 123 volcanoes analyzed, Santiaguito, Tacaná and Fuego are those with the highest score in the 3-factor VRR (H×E×V), while Ecuador, Marchena and Santiago are among the systems with the lowest score. Bárcena and Pinta score zero as there is no exposure. Although vulnerability significantly contributes to the VRR score, hazard and exposure are the main factors that define the risk of Latin American volcanic systems in the proposed 3-factor VRR, while resilience contributes to its reduction in the proposed 4-factor VRR strategy. In this regard, Arenal, Copahue, Villarrica, Ubinas, Irazú and Poás are the systems with the highest number of risk reduction strategies in place. Atitlán, Almolonga and Tecuamburro are the volcanic systems with the highest score in the 4-factor VRR [(H×E×V)/(Res+1)], combining moderate hazard, exposure and vulnerability and low resilience; Bárcena, Pinta, Ecuador, Marchena and Santiago receive the lowest scores due to no or low exposure. Santiaguito, Tacaná, El Chichón and Ceboruco are characterized by high scores in the 3-factor VRR and also stand out as some of those with few risk reduction strategies implemented; thus they have intermediate to high scores also in the 4-factor VRR. Recognizing that hazard is difficult to mitigate and reducing exposure may depend on hardly feasible relocation of infrastructure and already established communities, we emphasize that measures to reduce vulnerability and increase resilience should be promoted (e.g., creating redundancy/accessibility to infrastructure, carrying out risk assessment studies, implementing early warning systems, developing emergency plans and promoting educational activities).

Review article: Brief history of volcanic risk in the Neapolitan area (Campania, southern Italy): a critical review

The presence of three active volcanoes (Vesuvius, Campi Flegrei and Ischia island) along the coast of Naples did not contain the huge expansion of the urbanized zones around them. In contrast, since the Greco-Roman era, volcanoes have featured among the favourite sites for people colonizing the Campania region. The stable settlements around Vesuvius, Campi Flegrei caldera and Ischia were progressively enlarged, attaining a maximum growth rate between 1950 and 1980. Between 1982 and 1984, Neapolitans faced the last and most dramatic volcanic crises, which occurred at Campi Flegrei (Pozzuoli) without an eruption. Since that time, volcanologists have focused their attention on the problem of risks associated with eruptions in the Neapolitan area, but a systematic strategy to reduce the very high volcanic risk of this zone is still lacking. A brief history of volcanic risk in the Neapolitan district is narrated here in an effort to provide new food for thought for the scientific community that works for the mitigation of volcanic risk in this area.

A New Inclusive Volcanic Risk Ranking, Part 1: Methodology

The ever-increasing population living near active volcanoes highlights the need for the implementation of effective risk reduction measures to save lives and reduce the impact of volcanic unrest and eruptions. To help identify volcanic systems associated with potential high risk and prioritize risk reduction strategies, we introduce a new Volcanic Risk Ranking (VRR) methodology that integrates hazard, exposure, and vulnerability as factors that increase risk, and resilience as a factor that reduces risk. Here we present a description of the methodology using Mexican volcanoes as a case study, while a regional application to Latin American volcanoes is presented in a companion paper (Guimarães et al., submitted). With respect to existing strategies, the proposed VRR methodology expands the parameters associated with hazard and exposure and includes the analysis of 4 dimensions of vulnerability (physical, systemic, social, economic) and of resilience. In particular, we propose 41 parameters to be analyzed, including 9 hazard parameters, 9 exposure parameters, 10 vulnerability parameters and 13 resilience parameters. Since the number of parameters evaluated for each risk factor is different, they are normalized to have the same weight based on dedicated sensitivity analyses. In order to best illustrate the methodology, the proposed VRR is here applied to 13 Mexican volcanoes and compared with other approaches. We found that the volcanoes associated with the highest combination of hazard, exposure and vulnerability (3-factor VRR) for this geographic area are Tacaná and El Chichón regardless of the analyzed time window of eruption occurrence (i.e., <1 and <10 ka). Nonetheless, the volcanoes with eruption <1 ka that require the most urgent actions as associated with no or few resilience measures in place are Michoacán-Guanajuato Volcanic Field and San Martín Tuxtla (4-factor VRR); the top volcanoes in the 4-factor VRR with eruption <10 ka are Michoacán-Guanajuato Volcanic Field and Las Cumbres.

Time-window into the transcrustal plumbing system dynamics of Dominica (Lesser Antilles)

Dominica, one of the most magmatically active islands of the Lesser Antilles through its four active volcanoes, is likely host under its central part, below Morne Trois Pitons–Micotrin, to a well-established transcrustal mush system. Pre-eruptive spatiotemporal magma dynamics are examined for five, explosive, pumiceous eruptions of this volcano in the last 24 kyrs through a combined Crystal System Analysis and intracrystalline Fe–Mg interdiffusion timescales modelling approaches. Before all eruptions, two magmatic environments of close compositions have interacted. These interactions began ~ 10–30 years prior to the four smaller of these eruptions, with more sustained mixing in the last decade, accelerated in the last 2 years. This contrasts with the largest pumiceous eruption, involving deeper magmas, with magma interaction starting over roughly a century but with various patterns. This suggests a possibility that increasing reactivation signals could be registered at the surface some years before future eruptions, having significant implications for volcanic risk mitigation.

Review article: Brief history of volcanic risk in Neapolitan area (Campania, Southern Italy): a critical review

The presence of three active volcanoes (Vesuvius, Campi Flegrei and Ischia Island) along the coast of Naples did not constrained the huge expansion of the urbanized zones around them. On the contrary, since Greek-Roman era, volcanoes have been an attractor for people who colonized Campania region. Stable settlements around Vesuvius, Campi Flegrei caldera and the Island of Ischia were progressively enlarged, reaching the maximum growth-rate between 1950 and 1980. Between 1982 and 1984, Neapolitan people faced the last and most dramatic volcanic crises, occurred at Campi Flegrei (Pozzuoli), without an eruption. Since that time, volcanologists have focused the attention on the problem of risk associated to eruptions in Neapolitan area, but a systematic strategy to reduce the very high volcanic risk of this area still lacks. A brief history of volcanic risk in Neapolitan district is here reported, trying to obtain new food for thought for the scientific community which works to the mitigation of volcanic risk of this area.

Volcanic risk communication challenges in the global south: the case of Goma, Eastern Democratic Republic of Congo

<p>The city of Goma is located in the eastern region of the Democratic Republic of Congo. With around one million inhabitants, it is built on lava flows, 15 km south of the active Nyiragongo volcano. Historically, the town was affected twice by eruptions, in 1977 and 2002 and severe destructions were reported. At that time, no volcanic risk preparedness and management tools had been implemented, and communication during and after the eruption was not consistent enough to avoid panic and human casualties. Without an appropriate and accurate risk communication, people may adopt a behavior which can put them at risk, by increasing their vulnerability. Nineteen years after the last disaster, risk management still have to develop an effective risk preparedness strategy and integrate risk awareness raising tools. The aim of this ongoing doctoral research is the assessment of risk culture, building upon a risk perception assessment and identification of risk reduction measures to be enhanced.</p><p>A survey of 2224 adults among the general population of Goma was conducted in eight representative neighborhoods in order to assess the risk perception, the experience of the risk communication as well as the risk preparedness of inhabitants. We here present a first analysis of the results regarding the risk communication challenges. Goma is a dynamic town with a young population (80% are under 45 years old), living in relatively poor and large family (51% of households have 4-7 members and 31% 8-11 members; 57% of household have an income between 0-250$), with rather low education (47% is secondary level and 34% graduated). Language is one of the volcanic risk communication challenges in Goma: apart from French as the official language, Swahili as local, and English imposed by the large humanitarian sector, there are many dialects. Moreover, most communication tools are informal (social networks, friends and relatives…) and inhabitants mostly look for information on religion (22%), health (15%) and politics (12%), but not so much about risk reduction. Local radio (24%), television (14,5%) and social networks (13%) are the most preferred information channels. The city of Goma is also very dynamic: with a high migration rate, the population is growing and renewing itself regularly, to the point that risk communication must take into account the newcomers in order to be efficient. Additionally, our survey shows that experience of disasters and trust in decision-makers also provide a basis for effective risk communication.</p><p>By presenting, as examples, the communication chain during the 2002 Nyiragongo eruption, as well as a more recent example of miscommunication due to the publication, in the general public press, of a scientific article with significant uncertainties in eruption forecast modelling (leading to misinterpretation by non-expert readers), we will demonstrate that the cascading reactions may have consequences putting risk decision-makers and scientists in a difficult position, by provoking a feeling of mistrust and doubt among the population. Based on the Goma case study, we will show that risk communication in the global south is a major risk management challenge with complex issues.</p>

Particle size, leaf pubescence and condition of humidity at leaf surfaces are key factors determining the retention of volcanic ash on crop foliage.

<p>Volcanic ashfall negatively affects crops, causing major economic losses and jeopardising the livelihood of farmers in developing countries where agriculture is at volcanic risk. Ash on plant foliage reduces the amount of incident light, thereby limiting photosynthesis and plant yield. An excessive ash load may also result in mechanical plant damages, such as defoliation and breakage of the stem and twigs. Characterising crop vulnerability to ashfall is critical to conduct a comprehensive volcanic risk analysis. This is normally done by describing the relationship between the ash deposit thickness and the corresponding reduction in crop yield, i.e. a fragility function. However, ash depth measured on the ground surface is a crude proxy of ash retention on plant foliage as this metrics neglects other factors, such as ash particle size, leaf pubescence and condition of humidity at leaf surfaces, which are likely to influence the amount of ash that stays on leaves.</p><p>Here we report the results of greenhouse experiments in which we measured the percentage of leaf surface area covered by ash particles for one hairy leaf plant (tomato, Solanum lycopersicum L.) and one hairless leaf plant (chilli pepper, Capsicum annuum L.) exposed to simulated ashfalls. We tested six particle size ranges (≤ 90, 90-125, 125-250, 250-500, 500-1000, 1000-2000 µm) and two conditions of humidity at leaf surfaces, i.e. dry and wet. Each treatment consisted of 15 replicates. The tomato and chilli pepper plants exposed to ash were at the seven- and eight-leaf stage, respectively. An ash load of ~570 g m<sup>-2 </sup>was applied to each plant using a homemade ashfall simulator. We estimated the leaf surface area covered by ash from pictures taken before and immediately after the simulated ashfall. The ImageJ software was used for image processing and analysis.</p><p>Our results show that leaf coverage by ash increases with decreasing particle size. Exposure of tomato and chilli pepper to ash ≤ 90 μm always led to ~90% coverage of the leaf surface area. For coarser particles sizes (i.e. between 125 and 500 µm) and dry condition at leaf surfaces, a significantly higher percentage (on average 29 and 16%) of the leaf surface area was covered by ash in the case of tomato compared to chilli pepper, highlighting the influence of leaf pubescence on ash retention. In addition, for particle sizes between 90 and 500 µm, wetting of the leaf surfaces prior to ashfall enhanced the ash cover by 19 ± 5% and 34 ± 11% for tomato and chilli pepper, respectively.</p><p>These findings highlight that ash deposit thickness alone cannot describe the hazard intensity accurately. A thin deposit of fine ash (≤ 90 µm) will likely cover the entire leaf surface area, thereby eliciting a disproportionate effect on plant foliage compared to a thicker but coarser deposit. Similarly, for a same ash depth, leaf pubescence and humid conditions at the leaf surfaces will enhance ash retention, thereby increasing the likelihood of damage. Our study will contribute to improve the reliability of crop fragility functions used in volcanic risk assessment.</p>