Journal of Applied Volcanology
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Open Access journal
ISSN (Online) 2191-5040
Published by SpringerOpen [155 journals]
[10 followers] Follow
Open Access journal
ISSN (Online) 2191-5040
Published by SpringerOpen [155 journals]
- Using near-real-time monitoring data from Pu‘u
‘Ō‘ō vent at Kīlauea Volcano for training and
Abstract: Abstract Training non-scientists in the use of volcano-monitoring data is critical preparation in advance of a volcanic crisis, but it is currently unclear which methods are most effective for improving the content-knowledge of non-scientists to help bridge communications between volcano experts and non-experts. We measured knowledge gains for beginning-(introductory-level students) and novice-level learners (students with a basic understanding of geologic concepts) engaged in the Volcanoes Exploration Program: Pu‘u ‘Ō‘ō (VEPP) “Monday Morning Meeting at the Hawaiian Volcano Observatory” classroom activity that incorporates authentic Global Positioning System (GPS), tilt, seismic, and webcam data from the Pu‘u ‘Ō‘ō eruptive vent on Kīlauea Volcano, Hawai‘i (NAGT website, 2010), as a means of exploring methods for effectively advancing non-expert understanding of volcano monitoring. Learner groups consisted of students in introductory and upper-division college geology courses at two different institutions. Changes in their content knowledge and confidence in the use of data were assessed before and after the activity using multiple-choice and open-ended questions. Learning assessments demonstrated that students who took part in the exercise increased their understanding of volcano-monitoring practices and implications, with beginners reaching a novice stage, and novices reaching an advanced level (akin to students who have completed an upper-division university volcanology class). Additionally, participants gained stronger confidence in their ability to understand the data. These findings indicate that training modules like the VEPP: Monday Morning Meeting classroom activity that are designed to prepare non-experts for responding to volcanic activity and interacting with volcano scientists should introduce real monitoring data prior to proceeding with role-paying scenarios that are commonly used in such courses. The learning gains from the combined approach will help improve effective communications between volcano experts and non-experts during times of crisis, thereby reducing the potential for confusion and misinterpretation of data.
- The scientific–community interface over the fifteen-year eruptive
episode of Tungurahua Volcano, Ecuador
Abstract: Abstract The successful handling of Tungurahua’s frequent eruptions during 15 years via permanent instrumental monitoring and good community relations by the Instituto Geofísico of the Escuela Politécnica Nacional (IGEPN) is due to these factors: 1./ Instrumental monitoring of Tungurahua volcano by the IGEPN started a decade before the 1999 reactivation. In early 1999 increased background seismicity and high SO2 readings suggested that magma was stirring. 2./ The long-term participation of IGEPN scientists in both monitoring and volcanic studies has fostered an institutional memory and a knowledge base that is referential for providing early warnings and in aiding the authorities to make critical decisions in anticipation of dangerous volcanic behavior. 3./ The permanent presence of IGEPN scientists at Tungurahua’s Volcano Observatory (OVT) who oversee the monitoring operations and maintain close contact with the threatened community. 4./ Participation of volunteer volcano observers from the community (vigías) who convey their observations 24 hours/day via a pan-volcano UHF radio system. Challenges to the operation´s success include: identifying precursor geophysical signals before volcanic eruptions begin; financing OVT´s operations and real-time instrumental surveillance; assuring active involvement of experienced scientists at OVT; instructing new rotating public officials in volcanic hazards and volcano crisis management, as well as working alongside them during critical moments; maintaining positive working relations with the community. Here we report on volcano monitoring and risk reduction strategies that have served the IGEPN in a semi-rural environment, where ~30,000 people reside in high-risk zones. On reflection, we believe that our “bottom-up” approach has been effective and has merit. This approach developed gradually; our actions were in response to our instrumental monitoring activity of Tungurahua, providing credible information to the public and authorities and overcoming negative perceptions by the population. If there is a recipe, it is conditioned on good monitoring results and interpretation that is adequately and frequently communicated to those concerned, and over many years fostering a mutual trust among the actors. Some strategies described herein may not be pertinent at a volcano whose eruptive activity is short-lived.
- Trajectories of social vulnerability during the Soufrière Hills
Abstract: Abstract When some active volcanoes enter into an eruptive phase, they generate a succession of hazard events manifested over a multi-year period of time. Under such conditions of prolonged risk, understanding what makes a population vulnerable to volcanic threats is a complex and nuanced process, and must be analysed within the wider context of physical events, decisions, actions and inactions which may have accentuated the social differentiation of impacts. Further, we must acknowledge the temporal component of vulnerability, therefore our analyses must go beyond a transitory view to an understanding of the dynamics of vulnerability, particularly how inherent socio-economic conditions drive vulnerability today, and how patterns of vulnerability shift during the course of a long-lived crisis.
- The genesis of volcanic risk assessment for the Auckland engineering
lifelines project: 1996–2000
Abstract: Abstract The Auckland Engineering Lifelines Project (A.E.L.P.) was initiated by the Auckland Regional Council, New Zealand, in 1996 to reduce the damage to and downtime of utilities such as water, wastewater, gas, power, etc., resulting from a variety of natural and technological hazards. A key initial project was a volcanic risk assessment. This paper describes the methodology that was developed to specifically assess the volcanic risk to lifelines from the Auckland Volcanic Field and distal volcanic centres in the central North Island, the application of the risk assessment and further developments beyond the initial project.
- The influence of probabilistic volcanic hazard map properties on hazard
Abstract: Abstract Probabilistic volcanic hazard analysis is becoming an increasingly popular component of volcanic risk reduction strategies worldwide. While probabilistic hazard analyses offer many advantages for decision-making, displaying the statistical results of these analyses on a map presents new hazard communication challenges. Probabilistic information is complex, difficult to interpret, and associated with uncertainties. Conveying such complicated data on a static map image without careful consideration of user perspectives or context, may result in contrasting interpretations, misunderstandings, or aversion to using the map. Here, we present the results of interviews and surveys conducted with organisational stakeholders and scientists in New Zealand which explored how probabilistic volcanic hazard map properties influence map interpretation, understanding, and preference. Our results suggest that data classification, colour scheme, content, and key expression play important roles in how users engage with and interpret probabilistic volcanic hazard maps. Data classification was found to influence the participants’ perceived uncertainty and data reading accuracy, with isarithmic style maps reducing uncertainty and increasing accuracy best. Colour scheme had a strong influence on the type of hazard messages interpreted, with a red-yellow scheme conveying the message of a hazard distribution (high to low), and a red-yellow-blue scheme conveying the message of hazard state (present or absent) and/or risk. Multiple types of map content were found to be useful, and hazard curves were viewed as valuable supplements. The concept of “confidence” was more easily interpreted than upper and lower percentiles when expressing uncertainty on the hazard curves. Numerical and verbal expression in the key also had an influence on interpretation, with a combination of both a percent (e.g., 25%) and a natural frequency (e.g., 1 in 4) “probability” being the most inclusive and widely-understood expression. The importance of these map property choices was underscored by a high portion of participants preferring to receive maps in unalterable formats, such as PDF. This study illustrates how engaging with users in a bottom-up approach can complement and enhance top-down approaches to volcanic hazard mapping through a collaborative and integrative design process which may help to prevent miscommunications in a future crisis when maps are likely to be drafted and disseminated rapidly.
- Bridging Māori indigenous knowledge and western geosciences to reduce
social vulnerability in active volcanic regions
Abstract: Abstract A new pedagogical methodology is proposed to reduce the social vulnerability of indigenous communities occupying areas subject to volcanic activity, as a potential interactive approach between those communities, scientists, and scientific institutions. The multidisciplinary methodology aims to increase scientist’s understanding of the relationship between native inhabitants and active volcanoes in indigenous territories, and to improve the effective dissemination of information. Also, the proposed methodology offers to the local community the scientific knowledge in an understandable and useful way, in order to maximize people’s awareness of their exposure to volcanic activity. The procedure starts with the recognition of the local ancestral comprehension of the volcano and the cultural, ecological, and economical bonds between humans and volcanic processes. Subsequently, the transmission of the indigenous knowledge to the scientific community and the appropriation of geological knowledge by the children and teachers in a specific Māori primary school in New Zealand, allowed: (1) the establishment of a common language, (2) enhanced communication and collaboration between the participants involved in understanding and living with an active volcano, and (3) increased awareness about the relationship between humans and active volcanoes. A permanent application (and site-specific adjustment) of this method, and the use of the resulting teaching tools, could reduce social vulnerability and empower indigenous communities in the development of volcanic risk mitigation strategies by revitalizing and sharing knowledge, rather than imposing one epistemological system onto the other.
- Variations in community exposure to lahar hazards from multiple volcanoes
in Washington State (USA)
Abstract: Abstract Understanding how communities are vulnerable to lahar hazards provides critical input for effective design and implementation of volcano hazard preparedness and mitigation strategies. Past vulnerability assessments have focused largely on hazards posed by a single volcano, even though communities and officials in many parts of the world must plan for and contend with hazards associated with multiple volcanoes. To better understand community vulnerability in regions with multiple volcanic threats, we characterize and compare variations in community exposure to lahar hazards associated with five active volcanoes in Washington State, USA—Mount Baker, Glacier Peak, Mount Rainier, Mount Adams and Mount St. Helens—each having the potential to generate catastrophic lahars that could strike communities tens of kilometers downstream. We use geospatial datasets that represent various population indicators (e.g., land cover, residents, employees, tourists) along with mapped lahar-hazard boundaries at each volcano to determine the distributions of populations within communities that occupy lahar-prone areas. We estimate that Washington lahar-hazard zones collectively contain 191,555 residents, 108,719 employees, 433 public venues that attract visitors, and 354 dependent-care facilities that house individuals that will need assistance to evacuate. We find that population exposure varies considerably across the State both in type (e.g., residential, tourist, employee) and distribution of people (e.g., urban to rural). We develop composite lahar-exposure indices to identify communities most at-risk and communities throughout the State who share common issues of vulnerability to lahar-hazards. We find that although lahars are a regional hazard that will impact communities in different ways there are commonalities in community exposure across multiple volcanoes. Results will aid emergency managers, local officials, and the public in educating at-risk populations and developing preparedness, mitigation, and recovery plans within and across communities.
- Beyond the volcanic crisis: co-governance of risk in Montserrat
Abstract: Abstract Disaster risk governance is concerned with how institutions change in response to perturbations or, conversely, are able to remain static for long periods of time. In Montserrat, the volcanic eruption in 1995 produced unprecedented challenges for both local government authorities and the UK Government. The sharp and sustained rise in the level of volcanic risk combined with an inadequate response from UK and local authorities prompted a shift in governance arrangements, and when levels of risk declined these new configurations did not go back to their pre-crisis state. This paper focuses on one aspect of this governance transition: the relationship between the local Montserratian government and the UK government. Before the eruption Montserrat enjoyed high levels of political and fiscal independence from the UK in disaster risk management and other investment decisions, but the volcanic crisis highlighted low levels of capacity and the inherent instability in this system. A new co-governance regime was established after the crisis, characterised by greater UK intervention in local investment decisions and some loss of political sovereignty. On the other hand, Montserrat has become more integrated in regional and international disaster risk governance systems, and today the division of local and central responsibilities for different aspects of disaster risk management is much clearer than before the volcanic crisis. This paper demonstrates how disasters can create spaces for existing risk governance systems to be questioned and modified. The volcanic crisis led to a reconsideration of responsibilities and risk management practices by both Montserratian and UK authorities, and initiated a process of transformation in land-use and development planning that has substantially reduced levels of volcanic risk on the island. However, these benefits have to be weighed against loss of livelihoods for a significant proportion of the population and considerable social upheaval. Critical to the success of this new development model is the need for vertical coherence and dialogue between different stakeholders. Montserrat and UK risk governance systems are more integrated now, but unless communities are engaged in risk management decisions, Montserrat's low- risk development model could come unstuck. Small islands with large risks can learn a lot from the Montserrat experience.
- Improvements of volcanic ash fall forecasts issued by the Japan
Abstract: Abstract Since March 2008, the Japan Meteorological Agency (JMA) has operated a Volcanic Ash Fall Forecast (VAFF) system to issue forecasts of areas in Japan where ash falls are expected following volcanic eruptions. The hazardous effects of ash falls vary according to the quantity of ash generated and have different consequences for agriculture, communication and transport networks, and buildings. The prediction techniques based on the JMA Regional Atmospheric Transport Model were recently revised by the Meteorological Research Institute of JMA to allow predictions of the quantity and areas of ash fall, and areas to be affected by lapilli fall. JMA plans further improvements to the VAFF system to address the needs of people living near active volcanoes and to take into account expert advice in fields such as volcanology, disaster prevention, and broadcasting and medical services. The improved VAFF system will provide three types of information: a regular information before possible eruption, a brief preliminary forecast issued 5–10 minutes after an eruption, and a full forecast issued 20–30 minutes after an eruption. JMA has developed a table to accompany VAFFs that categorizes the hazardous effects for people according to various quantities of ash fall, and provides advice on preparedness measures and actions to be taken when an ash fall occurs. The new VAFF system will also provide predictions of areas of expected lapilli fall. JMA will start operation of the new VAFF system in spring 2015.
- Enhancing scientific response in a crisis: evidence-based approaches from
emergency management in New Zealand
Abstract: Abstract Contemporary approaches to multi-organisational response planning for the management of complex volcanic crises assume that identifying the types of expertise needed provides the foundation for effective response. We discuss why this is only one aspect, and present the social, psychological and organizational issues that need to be accommodated to realize the full benefits of multi-agency collaboration. We discuss the need to consider how organizational culture, inter-agency trust, mental models, information management and communication and decision making competencies and processes, need to be understood and accommodated in crisis management planning and delivery. This paper discusses how these issues can be reconciled within superordinate (overarching) management structures designed to accommodate multi-agency response that incorporates decision-making inputs from both the response management team and the science advisors. We review the science advisory processes within New Zealand (NZ), and discuss lessons learnt from research into the inter-organisational response to historical eruptions and exercises in NZ. We argue that team development training is essential and review the different types of training and exercising techniques (including cross training, positional rotation, scenario planning, collaborative exercises, and simulations) which can be used to develop a coordinated capability in multiagency teams. We argue that to truly enhance the science response, science agencies must learn from the emergency management sector and embark on exercise and simulation programs within their own organisations, rather than solely participating as external players in emergency management exercises. We thus propose a science-led tiered exercise program, with example exercise scenarios, which can be used to enhance both the internal science response and the interagency response to a national or international event, and provide direction for the effective writing and conduct of these exercises.
- Recognizing and tracking volcanic hazards related to non-magmatic unrest:
Abstract: Abstract Eruption forecasting is a major goal in volcanology. Logically, but unfortunately, forecasting hazards related to non-magmatic unrest is too often overshadowed by eruption forecasting, although many volcanoes often pass through states of non-eruptive and non-magmatic unrest for various and prolonged periods of time. Volcanic hazards related to non-magmatic unrest can be highly violent and/or destructive (e.g., phreatic eruptions, secondary lahars), can lead into magmatic and eventually eruptive unrest, and can be more difficult to forecast than magmatic unrest, for various reasons. The duration of a state of non-magmatic unrest and the cause, type and locus of hazardous events can be highly variable. Moreover, non-magmatic hazards can be related to factors external to the volcano (e.g., climate, earthquake). So far, monitoring networks are often limited to the usual seismic-ground deformation-gas network, whereas recognizing indicators for non-magmatic unrest requires additional approaches. In this study we summarize non-magmatic unrest processes and potential indicators for related hazards. We propose an event-tree to classify non-magmatic unrest, which aims to cover all major hazardous outcomes. This structure could become useful for future probabilistic non-magmatic hazard assessments, and might reveal clues for future monitoring strategies.
- Reducing risk from lahar hazards: concepts, case studies, and roles for
Abstract: Abstract Lahars are rapid flows of mud–rock slurries that can occur without warning and catastrophically impact areas more than 100 km downstream of source volcanoes. Strategies to mitigate the potential for damage or loss from lahars fall into four basic categories: (1) avoidance of lahar hazards through land-use planning; (2) modification of lahar hazards through engineered protection structures; (3) lahar warning systems to enable evacuations; and (4) effective response to and recovery from lahars when they do occur. Successful application of any of these strategies requires an accurate understanding and assessment of the hazard, an understanding of the applicability and limitations of the strategy, and thorough planning. The human and institutional components leading to successful application can be even more important: engagement of all stakeholders in hazard education and risk-reduction planning; good communication of hazard and risk information among scientists, emergency managers, elected officials, and the at-risk public during crisis and non-crisis periods; sustained response training; and adequate funding for risk-reduction efforts. This paper reviews a number of methods for lahar-hazard risk reduction, examines the limitations and tradeoffs, and provides real-world examples of their application in the U.S. Pacific Northwest and in other volcanic regions of the world. An overriding theme is that lahar-hazard risk reduction cannot be effectively accomplished without the active, impartial involvement of volcano scientists, who are willing to assume educational, interpretive, and advisory roles to work in partnership with elected officials, emergency managers, and vulnerable communities.
- Scientists’ views about lay perceptions of volcanic hazard and risk
Abstract: Abstract We present data from a survey of scientists from volcano observatories and monitoring institutions around the world. The scientists were asked about the hazards from the volcanoes that they work on, their perception of the likely magnitude and impacts of eruptions, and their views about local people’s awareness of the risk. They were also asked about how well different groups are trusted by local people, and about their views concerning the need to warn people about changes in the volcanic risk. We show that scientists were generally concerned about risk from the volcanoes that they worked on, and also that many scientists felt that their own view of the risk was different from that of locals. Perceived trust in scientists depended upon both social factors and volcanic risk. We discuss the implications of these results for precautionary decision-making on active volcanoes.
- An analysis of the issuance of volcanic alert levels during volcanic
Abstract: Abstract Volcano Alert Levels (VALs) are used by volcanologists to quickly and simply inform local populations and government authorities of the level of volcanic unrest and eruption likelihood. Most VALs do not explicitly forecast volcanic activity but, in many instances they play an important role in informing decisions: defining exclusion zones and issuing evacuation alerts. We have performed an analysis on VALs (194 eruptions, 60 volcanoes) to assess how well they reflect unrest before eruption and what other variables might control them. We have also looked at VALs in cases where there was an increase in alert level but no eruption, these we term 'Unrest without eruption' (UwE). We have analyzed our results in the context of eruption and volcano type, instrumentation, eruption recurrence, and the population within 30 km. We found that, 19% of the VALs issued between 1990 and 2013 for events that ended with eruption accurately reflect the hazard before eruption. This increases to ~30% if we only consider eruptions with a VEI ≥ 3. VALs of eruptions from closed-vent volcanoes are more appropriately issued than those from open-vents. These two observations likely reflect the longer and stronger unrest signals associated with large eruptions from closed vents. More appropriate VAL issuance is also found in volcanoes with monitoring networks that are moderately-well equipped (3-4 seismometers, GPS and gas monitoring). There is also a better correlation between VALs and eruptions with higher population density. We see over time (1990 to 2013) that there was an increase in the proportion of ‘UwE’ alerts to other alerts, suggesting increasing willingness to use VALs well before an eruption is certain. The number of accurate VALs increases from 19% to 55% if we consider all UwE alerts to be appropriate. This higher ‘success’ rate for all alerts (with or without eruption) is improving over time, but still not optimal. We suggest that the low global accuracy of the issuance of VALs could be improved by having more monitoring networks equipped to a medium level, but also by using probabilistic hazard management during volcanic crisis.
- Communicating the status of volcanic activity: revising New
Zealand’s volcanic alert level system
Abstract: Abstract The communication of scientific information to stakeholders is a critical component of an effective Volcano Early Warning System. Volcanic Alert Level (VAL) systems are used in many countries as a tool within early warning systems to communicate complex volcanic information in a simple form, from which response decisions can be made. Such communication tools need to meet the requirements of a wide range of end-users, including emergency managers, the aviation industry, media, and the public. They also need to be usable by scientists who determine the alert levels based on integration and interpretation of volcano observations and monitoring data. This paper presents an exploratory review of New Zealand’s 20-year old VAL system, and for the first time globally, describes the development of a VAL system based on a robust qualitative ethnographic methodology. This involved semi-structured interviews of scientists and VAL end-users, document analysis, and observations of scientists over three years as they set the VAL during multiple unrest and eruption crises. The transdisciplinary nature of this research allows the system to be revised with direct input by end-users of the system, highlighting the benefits of using social science methodologies in developing or revising warning systems. The methodology utilised in this research is applicable worldwide, and could be used to develop warning systems for other hazards. It was identified that there are multiple possibilities for foundations of VAL systems, including phenomena, hazard, risk, and magmatic processes. The revised VAL system is based on the findings of this research, and was implemented in collaboration with New Zealand’s Ministry of Civil Defence and Emergency Management in July 2014. It is used for all of New Zealand’s active volcanoes, and is understandable, intuitive, and informative. The complete process of exploring a current VAL system, revising it, and introducing it to New Zealand society is described.
- Santorini unrest 2011–2012: an immediate Bayesian belief network
analysis of eruption scenario probabilities for urgent decision support
Abstract: Abstract Unrest at the Greek volcanic island of Santorini in 2011–2012 was a cause for unease for some governments, concerned about risks to their nationals on this popular holiday island if an eruption took place. In support of urgent response planning undertaken by the UK government, we developed a rapid evaluation of different eruption scenario probabilities, using the Bayesian Belief Network (BBN) formulation for combining multiple strands of scientific and observational evidence. Here we present three alternative BBN models that were devised in early 2012 for assessing the situation: (1) a basic static net for evaluating probabilities at any one moment in time, utilising just four key unrest indicators; (2) a compound time-stepping net, extending the basic net to update probabilities through time as the indicators changed; and (3) a more comprehensive net, with multiple lines of other data and observations incorporated, reflecting diversity of modern multi-parameter monitoring techniques. A key conclusion is that, even with just three or four basic indicators, it is not feasible, or defensible, to attempt to judge mentally the implications of signs of unrest – a structured probabilistic procedure using Bayes’ Rule is a rational approach for enumerating evidential strengths reliably. In the Santorini case, the unrest, and official anxiety, diminished quite quickly and our approach was not progressed to the point where detailed consideration was given to BBN parameters, analysis of data uncertainty or the elicitation of expert judgements for quantifying uncertainties to be used in the BBN. Had this been done, the resulting scenario probabilities could have been adopted to determine likelihoods of volcanic hazards and risks caused by possible eruptive activity, as identified in a concurrent assessment of the scale and intensities of potential volcanic impacts (Jenkins et. al., Assessment of ash and gas hazard for future eruptions at Santorini Volcano, Greece. forthcoming). Ideally, such hazard and risk assessments should be elaborated in detail and critiqued well before crisis-level unrest develops – not initiated and implemented within a few hours just when a situation looks ominous. In particular, careful analysis of all information is required to determine and represent parameter uncertainties comprehensively and dependably.
- Risk reduction through community-based monitoring: the class="a-plus-plus">vigías of Tungurahua,
Abstract: Abstract Since 2000, a network of volunteers known as vigías has been engaged in community-based volcano monitoring, which involves local citizens in the collection of scientific data, around volcán Tungurahua, Ecuador. This paper provides the first detailed description and analysis of this well-established initiative, drawing implications for volcanic risk reduction elsewhere. Based on 32 semi-structured interviews and other qualitative data collected in June and July 2013 with institutional actors and with vigías themselves, the paper documents the origins and development of the network, identifies factors that have sustained it, and analyses the ways in which it contributes to disaster risk reduction. Importantly, the case highlights how this community-based network performs multiple functions in reducing volcanic risk. The vigías network functions simultaneously as a source of observational data for scientists; as a communication channel for increasing community awareness, understanding of hazard processes and for enhancing preparedness; and as an early warning system for civil protection. Less tangible benefits with nonetheless material consequences include enhanced social capital – through the relationships and capabilities that are fostered – and improved trust between partners. Establishing trust-based relationships between citizens, the vigías, scientists and civil protection authorities is one important factor in the effectiveness and resilience of the network. Other factors discussed in the paper that have contributed to the longevity of the network include the motivations of the vigías, a clear and regular communication protocol, persistent volcanic activity, the efforts of key individuals, and examples of successful risk reduction attributable to the activities of the network. Lessons that can be learned about the potential of community-based monitoring for disaster risk reduction in other contexts are identified, including what the case tells us about the conditions that can affect the effectiveness of such initiatives and their resilience to changing circumstances.
- Volcanic ashfall preparedness poster series: a collaborative process for
reducing the vulnerability of critical infrastructure
Abstract: Abstract Volcanic ashfall can be damaging and disruptive to critical infrastructure including electricity generation, transmission and distribution networks, drinking-water and wastewater treatment plants, roads, airports and communications networks. There is growing evidence that a range of preparedness and mitigation strategies can reduce ashfall impacts for critical infrastructure organisations. This paper describes a collaborative process used to create a suite of ten posters designed to improve the resilience of critical infrastructure organisations to volcanic ashfall hazards. Key features of this process were: 1) a partnership between critical infrastructure managers and other relevant government agencies with volcanic impact scientists, including extensive consultation and review phases; and 2) translation of volcanic impact research into practical management tools. Whilst these posters have been developed specifically for use in New Zealand, we propose that this development process has more widely applicable value for strengthening volcanic risk resilience in other settings.
- Perception of a chronic volcanic hazard: persistent degassing at Masaya
Abstract: Abstract This study takes a combined qualitative and quantitative approach to examining the chronic hazard posed by persistent degassing at Masaya volcano, Nicaragua. The gas is a highly salient threat in communities surrounding Masaya volcano, with the elevated salience level of his invisible hazard deriving from the highly perceptible impacts of the degassing; these include individual and material impacts such as increased prevalence of self-reported respiratory disease and decreased crop diversification and productivity. Qualitative results concur with findings from a quantitative assessment of ambient SO2 exposure using diffusion tubes: the current level of SO2 degassing far exceeds international guideline values, making it a likely cause of adverse health effects for the general population. Conversely contaminant levels of heavy and toxic metals in foodstuffs were found to be below international standards. A community-based integrated hazard mitigation approach identified by this research is the cultivation of crops, particularly pineapple (Ananas comosus) and pitaya (Hylocereus sp.), that are better able to withstand the local environmental conditions (e.g. increased atmospheric SO2 and acid gas deposition). Despite this, little is known regarding disaster response and risk reduction at the community level and the gas hazard is largely overlooked. This shows large scope for increasing resilience in collaboration with the community, through for example the development of community-level risk management committees, improvement and implementation of (gas) mitigation strategies and disaster preparedness approaches. By reducing the impacts of the chronic hazard posed by persistent volcanic degassing, resilience to acute hazards is also likely to improve.
- Retrospective analysis of uncertain eruption precursors at La
Soufrière volcano, Guadeloupe, 1975–77: volcanic hazard
assessment using a Bayesian Belief Network approach
Abstract: Background Scientists monitoring active volcanoes are increasingly required to provide decision support to civil authorities during periods of unrest. As the extent and resolution of monitoring improves, the process of jointly interpreting multiple strands of indirect evidence becomes increasingly complex. Similarities with uncertainties in medical diagnosis suggest a formal evidence-based approach, whereby monitoring data are analysed synoptically to provide probabilistic hazard forecasts. A statistical tool to formalize such inferences is the Bayesian Belief Network (BBN). By explicitly representing conditional dependencies between the volcanological model and observations, BBNs use probability theory to treat uncertainties in a rational and auditable manner, as warranted by the strength of the scientific evidence. A retrospective analysis is given for the 1976 Guadeloupe crisis, using a BBN to provide inferential assessment of the state of the evolving magmatic system and probability of incipient eruption. Conditional dependencies are characterized quantitatively by structured expert elicitation. Results Analysis of the available monitoring data suggests that at the height of the crisis the probability of magmatic intrusion was high, in accordance with scientific thinking at the time. The corresponding probability of magmatic eruption was elevated in July and August 1976 and signs of precursory activity were justifiably cause for concern. However, collective uncertainty about the future course of the crisis was also substantial. Of all the possible scenarios, the most likely outcome evinced by interpretation of observations on 31 August 1976 was 'no eruption’ (mean probability 0.5); the chance of a magmatic eruption/blast had an estimated mean probability of ~0.4. There was therefore no evidential basis for asserting one scenario to be significantly more likely than another. Conclusions Our analysis adds objective probabilistic expression to the volcanological narrative at the time of the 1976 crisis, and demonstrates that a formal evidential case could have supported the authorities' concerns about public safety and decision to evacuate. Revisiting the episode highlights many challenges for modern, contemporary decision making under conditions of considerable uncertainty, and suggests the BBN is a suitable framework for marshalling multiple, uncertain observations, model results and interpretations. The formulation presented here can be developed as a tool for ongoing use in the volcano observatory.