Journal of Applied Volcanology
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Open Access journal
ISSN (Online) 2191-5040
Published by SpringerOpen [154 journals]
[8 followers] Follow
Open Access journal
ISSN (Online) 2191-5040
Published by SpringerOpen [154 journals]
- Rapid emergency assessment of ash and gas hazard for future eruptions at
Santorini Volcano, Greece
Abstract: Abstract Hazard assessments for long-dormant volcanoes, where information is rarely available, typically have to be made rapidly and in the face of considerable uncertainty and often poor information. A conditional (assuming an eruption), scenario-based probabilistic approach to such an assessment is presented here for Santorini volcano (Greece). The rapid assessment was developed and implemented in response to the 2011-2012 unrest crisis in order to inform emergency management and planning. This paper synthesises the results presented to the Greek National Committee and scientific community involved. Two plausible eruptions at Santorini were investigated, using multiple inputs and dispersal models, based on observations of historic eruptions and expert judgement. For ash hazard, a ‘most likely’ eruption scenario was developed, characterised by slow lava extrusion over periods of one to two years with weak but persistent explosions and ash venting up to 3 km. A second ‘largest considered’ sub-Plinian explosive scenario assumed a 12 km high column of 4-h duration. For gas hazard, constant fluxes of 200 and 800 tons/day SO2 were assumed for the duration of the eruption scenarios, noting that there is very little evidence to constrain SO2 flux from Santorini eruptions. Statistical models of likely wind conditions with height and season were developed from decadal reanalysis time series showing that consistent low-altitude winds were rarely maintained for more than a few days. Stochastic models of ash (TEPHRA2, VOL-CALPUFF) and gas (AERMOD) dispersal provided outputs in the form of probability maps and exceedance probability curves for key loading and concentration thresholds at important locations on the island. The results from the rapid assessments presented in this paper confirm that ash and gas hazard is likely to be of concern if an eruption of Santorini occurs. Higher hazard may be expected to the south and east of the volcano, notably at important tourist and transport hubs. Low hazard to the north and northwest suggests that these may be suitable locations for emergency response centres and emergency critical infrastructure. This approach may provide a blueprint for rapid ash and gas assessment for other long-dormant volcanoes and we provide suggestions for refining the methods used.
- Ash fall impact on vegetation: a remote sensing approach of the Oldoinyo
Lengai 2007–08 eruption
Abstract: Abstract Impacts from ash fallout on the environment can be widespread and long lasting, even from moderate-size eruptions. Assessing ash impact on vegetation and the indirect impacts for people is often difficult in the field. Here it is assessed how satellite data can help to map vegetation affected by ash and how temporal analysis enables characterization of vegetation recovery rate. The 2007–08 eruption of Oldoinyo Lengai, north Tanzania, is here used as a case study. An 8 year-long (2005–2012) time series of half-monthly average of the Normalized Differential Vegetation Index (NDVI) is constructed at 250 m spatial resolution from the Moderate Resolution Image Spectro-radiometer (MODIS) sensor. Interpolated rainfall data is used to isolate NDVI values departing from the normal seasonal cycles. Month-to-month NDVI comparison, linear temporal trend analysis and Principal Component Analysis enable to identify a 11 × 4 km area over which ash fallout significantly affected the state of the vegetation. After the eruption’s end, time series of various recovery indices highlight a circumferential pattern in vegetation recovery. The estimated recovery time varies from more than 5 years to less than 6 months with increasing distance from the volcano. A non-linear moderate, but statistically significant, relationship is found between the recovery indices and the spatial variation of ash thicknesses measured in the field. Combining field and remote sensing constraints enable to re-assess the volume of the eruption to ~2 × 107 m3. The spatial pattern of the ash-affected area matches with the spatial contrast in the impact experienced by the local communities. The method applied here opens the scope to document impact and intensity of ash fallout in areas where systematic field work is not possible and to support recovery plans for populations affected by ash fallout.
- Disaster risk reduction and resettlement efforts at San Vicente
(Chichontepec) Volcano, El Salvador: toward understanding social and
Abstract: Abstract Despite a long history of volcanic debris flows on the northern flank of San Vicente Volcano, El Salvador, authorities and communities were ill-prepared for the lahars that occurred on Nov. 7–8, 2009. More than 250 people were killed by lahars resulting from shallow landslides, not to mention millions of dollars (US) in damage to houses, agriculture, and infrastructure. After the disaster, significant aid was invested in the region to reduce risk in future disasters. This case study uses the ethnographic tools of qualitative interviews, participant observation, and review of institutional documents to analyze two particular aspects of disaster risk reduction strategies in the town of Verapaz: 1) relocation of at-risk residents led by the Ministry of Housing and Urban Development, and 2) hazard monitoring and emergency management training programs led by Civil Protection, the University of El Salvador, and NGOs. The relocation effort, while effective at reducing physical vulnerability to debris flows, failed to incorporate livelihood, social networks, and cultural ties to homes in their project design and implementation. Since diverse livelihoods are keys to survival, and tightly-knit social networks help families share responsibilities and withstand shocks during hardships, many families returned to the high-risk area or opted not to relocate. Others have adapted using unanticipated strategies to benefit from the resettlement effort. On the other hand, the emergency management training and education programs valued local input, knowledge, and action, which has helped increase awareness and improved the overall capacity to manage emergencies through wide, local participation. The different approaches used in the two risk reduction initiatives reveal important lessons regarding the importance of community participation. Challenges derive from narrow understandings of vulnerability on the part of disaster risk reduction experts, who neglected to consider and understand kin networks and residence patterns that help maintain diverse livelihoods, as well as ensure safety and security. As demonstrated in the 2011 Tropical Depression 12E, effective public engagement and empowerment helped bridge the knowledge, awareness, and preparedness gaps that existed prior to the 2009 disaster.
- Legal framework and scientific responsibilities during volcanic crises:
the case of the El Hierro eruption (2011–2014)
Abstract: Abstract In recent years concerns have been growing in the scientific community over the definition of scientific responsibilities during emergencies, and the legal status of scientists involved in the corresponding decision-making. It is clear that the legal framework is one of the main elements affecting this issue; however, many factors may affect both the specific scientific decision-making and the definition of general scientific responsibilities. The situation will vary depending on the type and scale of emergency, and from place to place, even in the same country. There will be no such thing as a single, ideal solution. In the latest El Hierro volcanic crisis many factors have negatively affected the scientific management and have prevented an adequate definition of scientific responsibility. These factors have been detected and documented by the authors. They include excessive pressure due to human and economic issues, a poor legal framework with identifiable deficiencies, an Emergency Plan in which the Volcanic Activity/Alert Level (VAL), Emergency Response Level (ERL) and Volcanic Traffic Light (VTL) have been too rigidly linked, serious weaknesses in the management and structure of the Scientific Committee (SC), and more. Even though some of these problems have now been detected and certain solutions have already been proposed, the slowness and complexity of the bureaucratic processes are making it difficult to implement solutions.
- Training in crisis communication and volcanic eruption forecasting: design
and evaluation of an authentic role-play simulation
Abstract: Abstract We present an interactive, immersive, authentic role-play simulation designed to teach tertiary geoscience students in New Zealand to forecast and mitigate a volcanic crisis. Half of the participating group (i.e., the Geoscience Team) focuses on interpreting real volcano monitoring data (e.g., seismographs, gas output etc.) while the other half of the group (i.e., the Emergency Management Team) forecasts and manages likely impacts, and communicates emergency response decisions and advice to local communities. These authentic learning experiences were aimed at enhancing upper-year undergraduate students’ transferable and geologic reasoning skills. An important goal of the simulation was specifically to improve students’ science communication through interdisciplinary team discussions, jointly prepared, and delivered media releases, and real-time, high-pressure, press conferences. By playing roles, students experienced the specific responsibilities of a professional within authentic organisational structures. A qualitative, design-based educational research study was carried out to assess the overall student experience and self-reported learning of skills. A pilot and four subsequent iterations were investigated. Results from this study indicate that students found these role-plays to be a highly challenging and engaging learning experience and reported improved skills. Data from classroom observations and interviews indicate that the students valued the authenticity and challenging nature of the role-play although personal experiences and team dynamics (within, and between the teams) varied depending on the students’ background, preparedness, and personality. During early iterations, observation and interviews from students and instructors indicate that some of the goals of the simulation were not fully achieved due to: A) lack of preparedness, B) insufficient time to respond appropriately, C) appropriateness of roles and team structure, and D) poor communication skills. Small modifications to the design of Iterations 3 and 4 showed an overall improvement in the students’ skills and goals being reached. A communication skills instrument (SPCC) was used to measure self-reported pre- and post- communication competence in the last two iterations. Results showed that this instrument recorded positive shifts in all categories of self-perceived abilities, the largest shifts seen in students who participated in press conferences. Future research will be aimed at adapting this curricula to new volcanic and earthquake scenarios.
- 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.
- ‘Is Ash Falling?’, an online ashfall reporting tool in
support of improved ashfall warnings and investigations of ashfall
Abstract: Abstract The primary volcano hazard in Alaska is airborne ash, which endangers aircraft flying the busy North Pacific air routes and consequently affects global commerce. Downwind ashfall is also a significant threat to commerce, transportation and day-to-day activities in nearby Alaska communities. A web-enabled database, "Is Ash Falling?" has been developed to collect ashfall observations and encourage sample collections from the public during eruptions, enabling volcano observatory staff to concentrate on eruption response. Knowing the locations of filed ashfall reports improves public ashfall warnings and forecasts by providing on-the-ground checks for ash dispersion and fallout computer models and satellite imagery interpretation. Reports of ashfall are shared with emergency management agencies and the wider public. These reports also give scientists a more complete record of the amount, duration and other conditions of ashfall.
- 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.