Massey Research Online - Browsing by Author "Wilson TM"

Browsing by Author "Wilson TM"

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A modular framework for the development of multi-hazard, multi-phase volcanic eruption scenario suites
(Elsevier BV, 2022-07) Weir AM; Mead S; Bebbington MS; Wilson TM; Beaven S; Gordon T; Campbell-Smart C
Understanding future volcanic eruptions and their potential impact is a critical component of disaster risk reduction, and necessitates the production of salient, robust hazard information for decision-makers and end-users. Volcanic eruptions are inherently multi-phase, multi-hazard events, and the uncertainty and complexity surrounding potential future hazard behaviour is exceedingly hard to communicate to decision-makers. Volcanic eruption scenarios are recognised to be an effective knowledge-sharing mechanism between scientists and practitioners, and recent hybrid scenario suites partially address the limitations surrounding the traditional deterministic scenario approach. Despite advances in scenario suite development, there is still a gap in the international knowledge base concerning the synthesis of multi-phase, multi-hazard volcano science and end-user needs. In this study we present a new modular framework for the development of complex, long-duration, multi-phase, multi-hazard volcanic eruption scenario suites. The framework was developed in collaboration with volcanic risk management agencies and researchers in Aotearoa-New Zealand, and is applied to Taranaki Mounga volcano, an area of high volcanic risk. This collaborative process aimed to meet end-user requirements, as well as the need for scientific rigour. This new scenario framework development process could be applied at other volcanic settings to produce robust, credible and relevant scenario suites that are demonstrative of the complex, varying-duration and multi-hazard nature of volcanic eruptions. In addressing this gap, the value of volcanic scenario development is enhanced by advancing multi-hazard assessment capabilities and cross-sector collaboration between scientists and practitioners for disaster risk reduction planning.
A new volcanic multi-hazard impact model for water supply systems: Application at Taranaki Mounga, Aotearoa New Zealand
(Elsevier B.V., 2024-12-24) Porter H; Wilson TM; Weir A; Stewart C; Craig HM; Wild AJ; Paulik R; Fairclough R; Buzzella M
Water supply systems provide an essential service for society and are highly vulnerable to damage and disruption during volcanic eruptions. Impacts sustained by water supply systems during volcanic eruptions have resulted in prolonged and repeated supply outages. Previous approaches to assessing volcanic impacts to water supply systems have been relatively simplistic, based on hazard intensity thresholds, and only considering direct damage. There is a need for water supply risk assessment approaches informed by vulnerability models that consider the pivotal role of system design and indirect impacts; such as supply and demand fluctuations, personnel shortages, and disruptions to interdependent infrastructure networks. We present a whole-of-system volcanic vulnerability model and impact assessment framework for water supply systems that can be used to estimate system-wide impacts during future volcanic eruptions. This model is developed in collaboration with volcanic risk researchers and water supply engineers in Aotearoa New Zealand and applied to a case study in the Taranaki region for a long-duration and multi-hazard eruption scenario from the active stratovolcano Taranaki Mounga. The model provides an assessment of the functionality of water supply systems affected directly and indirectly by the scenario eruption, interdependent critical infrastructure services, and associated emergency management actions (e.g., evacuations). This scenario, and its modelled impacts, allows practitioners to explore potential mitigation and emergency response options. This framework can be applied in other volcanic contexts to assess impacts on water supplies from future eruptions, highlight key systemic vulnerabilities, and provide a basis for the prioritisation and implementation of risk management strategies.
Agriculture and forestry impact assessment for tephra fall hazard: fragility function development and New Zealand scenario application
(Volcanica, 2021-12-31) Craig HM; Wilson TM; Magill C; Stewart C; Wild AJ
Developing approaches to assess the impact of tephra fall on agricultural and forestry systems is essential for informing effective disaster risk management strategies. Fragility functions are commonly used as the vulnerability model within a loss assessment framework and represent the relationship between a given hazard intensity measure (HIM; e.g. tephra thickness) and the probability of impacts occurring. Impacts are represented using an impact state (IS), which categorises qualitative and quantitative statements into a numeric scale. This study presents IS schemes for pastoral, horticultural, and forestry systems, and a suite of fragility functions estimating the probability of each IS occurring for 13 sub-sectors. Temporal vulnerability is accounted for by a ‘temporality/seasonality coefficient,’ and a ‘fluoride toxicity coefficient’ is included to incorporate the increased vulnerability of pastoral farms when tephra is high in leachable fluoride. The fragility functions are then used to demonstrate a deterministic impact assessment with current New Zealand exposure.
Approaching the challenge of multi-phase, multi-hazard volcanic impact assessment through the lens of systemic risk: application to Taranaki Mounga
(Springer Nature, 2024-08-01) Weir AM; Wilson TM; Bebbington MS; Beaven S; Gordon T; Campbell-Smart C; Mead S; Williams JH; Fairclough R
Effective volcanic impact and risk assessment underpins effective volcanic disaster risk management. Yet contemporary volcanic risk assessments face a number of challenges, including delineating hazard and impact sequences, and identifying and quantifying systemic risks. A more holistic approach to impact assessment is required, which incorporates the complex, multi-hazard nature of volcanic eruptions and the dynamic nature of vulnerability before, during and after a volcanic event. Addressing this need requires a multidisciplinary, integrated approach, involving scientists and stakeholders to co-develop decision-support tools that are scientifically credible and operationally relevant to provide a foundation for robust, evidence-based risk reduction decisions. This study presents a dynamic, longitudinal impact assessment framework for multi-phase, multi-hazard volcanic events and applies the framework to interdependent critical infrastructure networks in the Taranaki region of Aotearoa New Zealand, where Taranaki Mounga volcano has a high likelihood of producing a multi-phase explosive eruption within the next 50 years. In the framework, multi-phase scenarios temporally alternate multi-hazard footprints with risk reduction opportunities. Thus, direct and cascading impacts and any risk management actions carry through to the next phase of activity. The framework forms a testbed for more targeted mitigation and response planning and allows the investigation of optimal intervention timing for mitigation strategies during an evolving eruption. Using ‘risk management’ scenarios, we find the timing of mitigation intervention to be crucial in reducing disaster losses associated with volcanic activity. This is particularly apparent in indirect, systemic losses that cascade from direct damage to infrastructure assets. This novel, dynamic impact assessment approach addresses the increasing end-user need for impact-based decision-support tools that inform robust response and resilience planning.
Quantifying economic risks to dairy farms from volcanic hazards in Taranaki, Aotearoa / New Zealand
(Copernicus Publications on behalf of the European Geosciences Union, 2025-04-29) McDonald NJ; Dowling L; Harvey EP; Weir AM; Bebbington MS; Bui N; Magill C; Craig HM; Mcdonald GW; Monge JJ; Cronin SJ; Wilson TM; Walker D
The volcanic hazard and risk science for Taranaki Mounga (Taranaki volcano) in Aotearoa / New Zealand is in an advanced state, with robust probabilistic data and a series of direct impact scenarios modelled for the region. Here, we progress this work and demonstrate a method to provide risk information that is nuanced for factors such as location and economic sector and considers the dynamic nature of volcanism with hazards potentially repeated over time. Recognising the fundamental importance of the dairy sector to Taranaki region, this paper provides valuable insights into the potential impacts and risks to heterogeneous dairy cattle farms within the region from volcanic hazards. We provide volcanic impact and risk metrics in economic or monetary terms in order to improve its relevance to decision-makers while reducing the complexity of the impacts. To do this, we developed a dynamic, multi-event farm system model of response and recovery, which takes in hazard intensity metrics from a series of volcanic events and generates the resulting annualised revenues, expenditures, and recovery costs through time. The model is formulated in a generalised way such that it can be used for various other hazard types and agricultural land uses. In our application of the model, we create and apply a suite of 10 000 simulations that capture different iterations of possible future volcanic activity over a 50-year period. These include the generation of lahars following eruptions and associated failures for transport and water supply networks. Farms at five case study locations were modelled to capture the diversity in farm management and the spatial variation in hazard intensities and likelihoods across the region. We provide summaries of the distributions of economic impacts generated, both for individual events and for the 50-year volcanic future horizon. Drawing the information together, we also summarise the results for each case study farm in terms of the value at risk statistic. For the case study farms with negligible lahar risk, we find, with 90 % confidence, that volcanic losses over the next 50 years will not exceed around 10 % of property value. By comparison, for the farm with the most severe lahar and ashfall exposure, we find that, at the same level of confidence, losses extend to approximately half the property value. These results indicate that with access to sufficient risk information, we should anticipate volcanic risk as playing an important role in shaping the future dairy sector in Taranaki region. The modelling pipeline and assessment metrics demonstrated in this paper could be used to assess mitigation and adaptation strategies to reduce the risk from volcanic hazards and improve the resilience of farm businesses.
Quantifying systemic vulnerability of interdependent critical infrastructure networks: A case study for volcanic hazards
(Elsevier Ltd., 2024-11-23) Weir AM; Wilson TM; Bebbington MS; Campbell-Smart C; Williams JH; Fairclough R
Infrastructure networks are vital for the communities and industries that rely on their continued operation. Disasters stress these complex networks and can provoke systemic disruptions that extend far beyond the spatial footprint of hazards. An enduring challenge for assessing infrastructure networks within disaster impact assessment frameworks has been to adequately quantify the high spatial interdependence of these networks, and to consider risk management interventions through time. This is of particular importance for volcanic eruptions, which can produce multiple hazards over highly variable spatiotemporal extents. In this study, we present a methodology for the quantification of systemic vulnerability of infrastructure networks, which can be coupled with physical vulnerability models for the purpose of impact assessment. The two-part methodology first quantifies the haard-agnostic criticality of infrastructural components, inclusive of interdependencies, and then incorporates representative hazard spatial footprints to derive the systemic vulnerability. We demonstrate this methodology using the case study of volcanic eruptions from Taranaki Mounga volcano, Aotearoa New Zealand, where there are many industrial sites of national importance, and a high likelihood of a complex multi-hazard volcanic eruption. We find a considerable increase in the systemic vulnerability of electricity and natural gas network components after incorporating infrastructure interdependencies, and a further increase in the systemic vulnerability of these critical components when cross-referenced with potential volcanic hazard spatial extent. The methodology of this study can be applied to other areas of interest in both its hazard-agnostic or hazard-dependent form, and the systemic vulnerability quantification should be incorporated into impact assessment frameworks.
Rapid remote volcanic ashfall impact assessment for the 2022 eruption of Hunga volcano, Tonga: a bespoke approach and lessons identified
(Springer Nature, 2024-10-28) Weir AM; Williams JH; Wilson TM; Hayes JL; Stewart C; Leonard GS; Magill C; Jenkins SF; Williams S; Craig HM; Kula T; Fraser S; Pomonis A; Gunasekera R; Daniell JE; Coultas E
When disasters occur, rapid impact assessments are required to prioritise response actions, support in-country efforts and inform the mobilisation of aid. The 15 January 2022 eruption of Hunga volcano, Tonga, and the resulting atmospheric shockwave, ashfall, underwater mass disturbance and tsunami, caused substantial impacts across the Kingdom of Tonga. Volcanic impacts on the scale observed after the eruption are rare, necessitating a reliance on international advice and assistance. The situation was complicated by the loss of Tonga’s international submarine fibreoptic cable (causing a complete loss of communications for approximately 20 days) along with border closures due to the COVID-19 pandemic. A need emerged for a rapid remote volcanic impact assessment and provision of specialist advice to help inform the response of international partners. Here we present a novel methodology for conducting rapid remote volcanic ashfall impact assessments, conducted over a 10-day period following the eruption. We used three different hazard models for ashfall thickness across the main island of Tongatapu and available asset information and vulnerability functions for buildings, agriculture, electricity networks, water supply and roads, to provide initial estimates of losses due to ashfall from the 15 January eruption. For buildings, we estimated losses both as total losses and as percentages of the total replacement cost of buildings on Tongatapu. For agriculture, we made probabilistic estimates of production losses for three different crop classes. For ashfall clean-up, we estimated ranges of ashfall volumes requiring clean-up from road surfaces and roofs. For water supply, electricity networks and roads, our analysis was limited to assessing the exposure of important assets to ashfall, as we had insufficient information on system configurations to take the analysis further. Key constraints on our analysis were the limited nature of critical infrastructure asset inventories and the lack of volcanic vulnerability models for tropical regions including Pacific Island nations. Key steps towards iteratively improving rapid remote impact assessments will include developing vulnerability functions for tropical environments as well as ground-truthing estimated losses from remote approaches against in-person impact assessment campaigns.
Tephra fall impacts to buildings: the 2017–2018 Manaro Voui eruption, Vanuatu
(Frontiers Media S.A., 2024-08-15) Jenkins SF; McSporran A; Wilson TM; Stewart C; Leonard G; Cevuard S; Garaebiti E; Varley N
Building damage from tephra falls can have a substantial impact on exposed communities around erupting volcanoes. There are limited empirical studies of tephra fall impacts on buildings, with none on tephra falls impacting traditional thatched timber buildings, despite their prevalence across South Pacific island nations and parts of Asia. The 2017/2018 explosive eruption of Manaro Voui, Ambae Island, Vanuatu, resulted in damage to traditional (thatched timber), non-traditional (masonry), and hybrid buildings from tephra falls in March/April and July 2018. Field and photographic surveys were conducted across three separate field studies with building characteristics and damage recorded for a total of 589 buildings. Buildings were classified using a damage state framework customised for this study. Overall, increasing tephra thicknesses were related to increasing severity of building damage, corroborating previous damage surveys and vulnerability estimates. Traditional buildings were found to be less resistant to tephra loading than non-traditional buildings, although there was variation in resistance within each building type. For example, some traditional buildings collapsed under ∼40 mm thickness while others sustained no damage when exposed to >200 mm. We attribute this to differences in the pre-eruption condition of the building and the implementation of mitigation strategies. Mitigation strategies included covering thatched roofs with tarpaulins, which helped shed tephra and consequently reduced loading, and providing an internal prop to the main roof beam, which aided structural resistance. As is typical of post-event building damage surveys, we had limited time and access to the exposed communities, and we note the limitations this had for our findings. Our results contribute to the limited empirical data available for tephra fall building damage and can be used to calibrate existing fragility functions, improving our evidence base for forecasting future impacts for similar construction types globally.
Volcanic ballistic projectile deposition from a continuously erupting volcano: Yasur Volcano, Vanuatu
(Presses universitaires de Strasbourg, 2020-08-25) Fitzgerald RH; Kennedy BM; Gomez C; Wilson TM; Simons B; Leonard GS; Matoza RS; Jolly AD; Garaebiti E
Volcanic Ballistic Projectiles (VBPs) are the main hazard to life and infrastructure from Strombolian eruptions. This eruption style is a tourist drawcard, exposing people to VBP hazard. Most of the research on VBPs to date has been focussed on understanding how they form and their trajectory. However, little focus has been placed on how they are spatially distributed within VBP fields or the inclusion of these data into hazard and risk assessments. In this study, we used a drone to image the east and south flanks of Yasur Volcano, Vanuatu, and cameras, infrasound, and seismicity to record explosions from 28 July to 2 August and 17 to 19 October 2016. We present the mapped spatial distribution of VBPs from the two trips, assessing how the VBP field changes with distance and direction from the vent, and how eruption dynamics influence these changes. We found that the VBP spatial density and median diameter decrease with distance from the crater. Spatial density was also found to vary with direction around the crater, with higher spatial densities found in the S-SSE than other directions. Combined with observations of explosions, we attribute the changes in spatial density to explosion directionality. Our evidence for directionality results in considerable variation in summit VBP hazard and is an important, but by no means the sole, consideration for VBP hazard and risk assessments.

Browsing by Author "Wilson TM"

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