Browsing by Author "Leonard G"

Now showing 1 - 5 of 5
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    Citizen science as a catalyst for community resilience building: A two-phase tsunami case study
    (Massey University, 2020-06) Doyle EEH; Lambie E; Orchiston C; Becker JS; McLaren L; Johnston D; Leonard G
    The role of citizen science in natural hazard risk awareness, assessment, mitigation, and preparedness is being recognised as an important element of disaster risk reduction. Citizen science has potential as a collaborative resilience building activity that can help build the capacity of, and relationships between, individuals, communities, and institutions to prepare and respond to disaster. Specifically, citizen science can increase resilience by building the collective and self-efficacy of individuals, organisations, and communities as well as other factors such as enhancing planning, coping mechanisms, social capital, community participation, leadership, empowerment, trust, and a sense of community. We present a case study of a two-phased citizen science initiative related to tsunami preparedness and response, undertaken between 2015 and 2016 in Orewa, Auckland, Aotearoa New Zealand. The activities of the first phase acted as a catalyst for the second phase and thus contributed directly to resilience building. Phase One was a citizen-initiated, co-developed survey on tsunami preparedness and intended response. The results from the survey, showing that participants had a low understanding of appropriate response to a potential tsunami threat, were used by community leaders to develop a community preparedness and awareness-building exercise: Phase Two. Phase Two was a joint citizen and agency-facilitated tsunami evacuation exercise “Ahead of the Wave”, with science-led data collection on evacuation numbers and timing. This initiative was aimed at improving the response capacity of a coastal community at risk of tsunami and was initiated by the community itself with support from other agencies. We present an overview of the methodological approaches taken to understand community resilience to tsunami risk in Orewa. Further, we highlight the importance that researchers working in the citizen science space must recognise the time required to invest in co-production and the importance of understanding the different motivations of organisations and individuals.
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    Development of a Bayesian event tree for short-term eruption onset forecasting at Taupō volcano
    (Elsevier BV, 2022-12) Scott E; Bebbington M; Wilson T; Kennedy B; Leonard G
    Taupō volcano, located within the Taupō Volcanic Zone (TVZ) in the central North Island of Aotearoa-New Zealand, is one of the world's most active silicic caldera systems. Silicic calderas such as Taupō are capable of a broad and complex range of volcanological activity, ranging from minor unrest episodes to large destructive supereruptions. A critical tool for volcanic risk management is eruption forecasting. The Bayesian Event Tree for Eruption Forecasting (BET_EF) is one probabilistic eruption forecasting tool that can be used to produce short-term eruption forecasts for any volcano worldwide. A BET_EF model is developed for Taupō volcano, informed by geologic and historic data. Monitoring parameters for the model were obtained through a structured expert elicitation workshop with 30 of Aotearoa-New Zealand's volcanologists and volcano monitoring scientists. The eruption probabilities output by the BET_EF model for Taupō volcano's 17 recorded unrest episodes (between 1877 and 2019) were examined. We found time-inhomogeneity in the probabilities stemming from both the changes over time in the monitoring network around Taupō volcano and increasing level of past data (number of non-eruptive unrest episodes). We examine the former issue through the lens of the latest episodes, and the latter by re-running the episodes assuming knowledge of all 16 other episodes (calibration to 2021 data). The time variable monitoring network around Taupō volcano and parameter weights had a substantial impact on the estimated probabilities of magmatic unrest and eruption. We also note the need for improved monitoring and data processing at Taupō volcano, the existence of which would prompt updates and therefore refinements in the BET_EF model.
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    Hawke's Bay Regional Alerting Systems Review
    (2021-12-15) Tan M; Leonard G; Johnston D
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    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.
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    Volcano breath: a rare 'vog' event in the eastern Bay of Plenty, Aotearoa New Zealand
    (Australian Institute for Disaster Resilience, 2022-04-14) Stewart C; Iremonger S; Rosenberg M; Leonard G
    Whakaari/White Island, located 50 km offshore and north of Whakatāne in the eastern Bay of Plenty, Aotearoa New Zealand is the country’s most active volcano. For more than a century, it has been in a state of constant unrest punctuated by small but hazardous eruptions. Often, the volcano emits a plume of water vapour and gases that are visible from the mainland. Residents of Whakatāne were reminded of Whakaari’s ‘volcano breath’ when a rare ‘vog’ episode occurred on 9 November 2021.