Willy Aspinall

Willy Aspinall
Aspinall & Associates

BSc PhD CSci CGeol FGS

About

190
Publications
49,518
Reads
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5,411
Citations
Additional affiliations
January 2008 - March 2020
University of Bristol
Position
  • Professor
May 1970 - December 1982
University of the West Indies, St. Augustine
Position
  • Research Associate

Publications

Publications (190)
Article
Full-text available
Formalised elicitation of expert judgements has been used to help tackle several problematic societal issues, including volcanic crises and pandemic threats. We present an expert elicitation exercise for Piton de la Fournaise volcano, La Réunion island, held remotely in April 2021. This involved 28 experts from nine countries who considered a hypot...
Article
Full-text available
Risk assessment in communities or regions typically relies on the determination of hazard scenarios and an evaluation of their impact on local systems and structures. One of the challenges of risk assessment for infrastructure operators is how to identify the most critical scenarios that are likely to represent unacceptable risks to such assets in...
Preprint
We describe a method for calculating the probability that a distal geographic location is impacted by a pyroclastic density current (PDC) of a given size, considering the key related uncertainties. Specifically, we evaluate the minimum volume and mass of a PDC generated at the Aso caldera (Japan) that might affect each of three distal infrastructur...
Article
We describe an algorithm for producing an approximate 95% confidence interval for the bulk volume of tephra fall deposits, based on point-referenced tephra thickness measurements, and expert judgement. Applied to the Aso-4 eruption, our algorithm gives a 95% CI of [220 km3, 370 km3]. One component of our algorithm is an estimated thickness surface,...
Preprint
Full-text available
Improved high-resolution paleo records of atmospheric carbon dioxide (CO2) concentrations and reconstructions of Earth’s surface temperature are available. We analyze one authoritative Pleistocene data set to explore how the climate sensitivity parameter S varies under different system states, using linear regression of mean annual surface temperat...
Article
Full-text available
Drawing on risk methods from volcano crises, we developed a rapid COVID-19 infection model for the partial return of pupils to primary schools in England in June and July 2020, and a full return in September 2020. The model handles uncertainties in key parameters, using a stochastic re-sampling technique, allowing us to evaluate infection levels as...
Preprint
Full-text available
The SARS-CoV-2 epidemic has had major impacts on children's education, with schools required to implement infection control measures that have led to long periods of absence and classroom closures. We develop an agent-based epidemiological model of SARS-CoV-2 transmission that is applied to model infection within school classrooms, with a contact m...
Article
Volcano-tectonic (VT) earthquake swarms are usual precursors to volcanic eruptions and their dynamic phenomenologies are an invaluable eruption forecasting tool. A power-law relationship between cumulative seismic moment release and intrusion volume has been proposed for both well injection sites and VT swarms. Here we compile data from 17 geodetic...
Article
Future occurrence of explosive eruptive activity at Cotopaxi and Guagua Pichincha volcanoes, Ecuador, is assessed probabilistically, utilizing expert elicitation. Eight eruption types were considered for each volcano. Type event probabilities were evaluated for the next eruption at each volcano and for at least one of each type within the next 100...
Preprint
Full-text available
Risk assessment in communities or regions typically relies on the determination of hazard scenarios and an evaluation of their impact on local systems and structures. One of the challenges of risk assessment for infrastructure operators is how to identify the most critical scenarios that are likely to represent unacceptable risks to such assets in...
Chapter
In this chapter, I trace my introduction to the Classical Model and to the thoughts and philosophy of Roger Cooke, and then go on to recount some experiences of acting as a facilitator in many real world and sometimes crucial expert elicitations. The essence of my own history is that it took me a very long time to start to understand, and appreciat...
Article
Full-text available
Personal contacts drive COVID-19 infections. After being closed (23 March 2020) UK primary schools partially re-opened on 1 June 2020 with social distancing and new risk mitigation strategies. We conducted a structured expert elicitation of teachers to quantify primary school contact patterns and how contact rates changed upon re-opening with risk...
Article
Illnesses transmitted by food and water cause a major disease burden in the United States despite advancements in food safety, water treatment, and sanitation. We report estimates from a structured expert judgment study using 48 experts who applied Cooke’s classical model of the proportion of disease attributable to 5 major transmission pathways (f...
Preprint
Food insecurity is associated with increased risk for several health conditions and with increased national burden of chronic disease. Key determinants for household food insecurity are income and food costs. Forecasts show household disposable income for 2020 expected to fall and for 2021 to rise only slightly. Prices are forecast to rise. Thus, f...
Article
Full-text available
Stromboli volcano (Italy), always active with low energy explosive activity, is a very attractive place for visitors, scientists, and inhabitants of the island. Nevertheless, occasional more intense eruptions can present a serious danger. This study focuses on the modeling and estimation of their inter-event time and temporal rate. With this aim we...
Preprint
Full-text available
Background Contact patterns are the drivers of close-contacts infections, such as COVID-19. In an effort to control COVID-19 transmission in the UK, schools were closed on 23 March 2020. With social distancing in place, Primary Schools were partially re-opened on 1 June 2020, with plans to fully re-open in September 2020. The impact of social dista...
Preprint
Full-text available
We have constructed a COVID-19 infection hazard model for the return of pupils to the 16,769 state Primary Schools in England that takes into account uncertainties in model input parameters. The basic probabilistic model estimates likely number of primary schools with one or more infected persons under three different return-to-school circumstances...
Preprint
Full-text available
Abstract. Improved high-resolution paleo records of atmospheric carbon dioxide (CO<sub>2</sub>) concentrations and reconstructions of Earth’s surface temperature are available. We analyse one authoritative Pleistocene dataset to explore how the climate sensitivity parameter S varies under different system states, using linear regression of mean ann...
Conference Paper
Full-text available
Flank eruptions at Mt. Etna volcano are often related to the occurrence of strong earthquakes. Nevertheless, this is not always the case, and the relationship has to be modeled in probabilistic terms using Data Science. The topic has been investigated in a few studies, starting in the 80s and the 90s. This statistical analysis produced a clear resu...
Article
Full-text available
IntroductionFood insecurity is associated with increased risk for several health conditions and with poor chronic disease management. Key determinants for household food insecurity are income and food costs. Whereas short-term household incomes are likely to remain static, increased food prices would be a significant driver of food insecurity.Objec...
Conference Paper
The assessment of the seismic fragility of water networks is the key to characterizing their risk exposure to strong earthquakes. In the HORIZON2020 IMPROVER project, we focused our attention on the water network of Barreiro, a municipality close to Lisbon, Portugal. To determine vulnerability to ground shaking, the seismic fragility of each key co...
Article
Full-text available
“Few, beside the student of such phenomena, will be able to realize what would have resulted from a more concentrated liberation of the accumulating energy if, for instance, instead of being separated into moderate earth movements and gas emissions spread over more than a 100 weeks of time, all this energy had been manifested in a single week? It i...
Article
Full-text available
The detection of prion protein in widely used urine-derived fertility drugs has raised the possibility that prions from urine donors with (asymptomatic) prion disease could be present in these drugs. A high level of uncertainty exists regarding this issue. An international expert panel provided judgments related to prion disease transmission throug...
Article
Full-text available
Despite considerable advances in process understanding, numerical modeling, and the observational record of ice sheet contributions to global mean sea-level rise (SLR) since the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change, severe limitations remain in the predictive capability of ice sheet models. As a consequence...
Preprint
Full-text available
A key driver of household food insecurity is the balance between household disposable income and food prices. In the UK in recent years, many households have relied on charitable food banks in order to eat. The UK exit of the EU (Brexit) is expected to have significant influence across the economy, including on employment, wages and prices. We use...
Article
Full-text available
Abstract: Carbon capture and geological storage (CCS) is identified within the portfolio of mitigation options for climate change. Each value chain activity of large scale integrated projects (capture, transport, injection and storage) includes uncertainties and hence potential risks with respect to both environmental and human health protection. W...
Article
Full-text available
Bayesian Networks (BNs) are probabilistic graphical models that provide a robust and flexible framework for understanding complex systems. Limited case studies have demonstrated the potential of BNs in modeling multiple data streams for eruption forecasting and volcanic hazard assessment. Nevertheless, BNs are not widely employed in volcano observa...
Article
Full-text available
This paper discusses how epistemic uncertainties are considered in a number of different natural hazard areas including floods, landslides and debris flows, dam safety, droughts, earthquakes, tsunamis, volcanic ash clouds and pyroclastic flows, and wind storms. In each case it is common practice to treat most uncertainties in the form of aleatory p...
Article
Full-text available
Part 1 of this paper has discussed the uncertainties arising from gaps in knowledge or limited understanding of the processes involved in different natural hazard areas. Such deficits may include uncertainties about frequencies, process representations, parameters, present and future boundary conditions, consequences and impacts, and the meaning of...
Article
Full-text available
Part 1 of this paper has discussed the uncertainties arising from gaps in knowledge or limited understanding of the processes involved in different natural hazard areas. Such deficits may include uncertainties about frequencies, process representations, parameters, present and future boundary conditions, consequences and impacts, and the meaning of...
Article
Full-text available
This paper discusses how epistemic uncertainties are currently considered in the most widely occurring natural hazard areas, including floods, landslides and debris flows, dam safety, droughts, earthquakes, tsunamis, volcanic ash clouds and pyroclastic flows, and wind storms. Our aim is to provide an overview of the types of epistemic uncertainty i...
Chapter
Full-text available
When a volcano emerges from dormancy into a phase of unrest, the civil protection authorities charged with managing societal risks have the unenviable responsibility of making difficult decisions balancing numerous competing societal, political and economic considerations. A volcano that is threatening to erupt requires sound risk assessments incor...
Article
Full-text available
The dramatic rise in Oklahoma seismicity since 2009 is due to wastewater injection. The role of injection depth is an open, complex issue, yet critical for hazard assessment and regulation. We developed an advanced Bayesian Network to model joint conditional dependencies between spatial, operational, and seismicity parameters. We found injection de...
Chapter
The Classical Model (CM) is a performance-based approach for mathematically aggregating judgements from multiple experts, when reasoning about target questions under uncertainty. Individual expert performance is assessed against a set of seed questions, items from their field, for which the analyst knows or will know the true values, but the expert...
Chapter
The BN was constructed by performing a systematic review of the key features, events, and processes relating specifically to the single issue of the extent to which climate change could affect biosphere radiological risks due to a release from a repository; in this exploratory exercise, the approach was applied to four different climate change scen...
Chapter
This chapter first notes the emerging role of structured expert judgment in radioactive waste management and geological disposal facility siting decisions, and describes the properties and attributes of the elicitation method adopted for both case histories. The first, discussed here, is a contribution to a major geological disposal facility siting...
Article
Full-text available
Background Recently the World Health Organization, Foodborne Disease Burden Epidemiology Reference Group (FERG) estimated that 31 foodborne diseases (FBDs) resulted in over 600 million illnesses and 420,000 deaths worldwide in 2010. Knowing the relative role importance of different foods as exposure routes for key hazards is critical to preventing...
Data
Supporting technical information on the Cooke’s Classical Model. Supporting technical information on the Cooke’s Classical Model. (PDF)
Data
Data file including anonymized responses from all experts. Data file including anonymized responses from all experts on food source attribution for the WHO FERG expert elicitation. (XLSX)
Data
Median proportion of total foodborne cases attributed to exposure to specified foods, by subregions for selected bacteria. Median proportion of total foodborne cases attributed to exposure to specified foods, by subregions for selected bacteria. (PDF)
Data
Percent of foodborne incidence attributable to food-specific exposures (means and medians). Percent of foodborne incidence attributable to food-specific exposures (means and medians). (PDF)
Data
Example elicitation instrument: Enteric pathogens food source attribution for the WHO FERG expert elicitation on food source attribution. Example elicitation instrument: Enteric pathogens food source attribution for the WHO FERG expert elicitation on food source attribution. (XLS)
Data
Median proportion of total foodborne cases attributed to exposure to specified foods, by subregions for selected parasites. Median proportion of total foodborne cases attributed to exposure to specified foods, by subregions for selected parasites. (PDF)
Data
Calibration (seed) questions for microbiological hazards. Calibration questions for microbiological hazards. (XLSX)
Article
Full-text available
Scour (localised erosion) during flood events is one of the most significant threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important to many infrastructure owners, and is supported by industry guidanc...
Article
Full-text available
Following a cessation in eruptive activity it is important to understand how a volcano will behave in the future and when it may next erupt. Such an assessment can be based on the volcano's long-term pattern of behaviour and insights into its current state via monitoring observations. We present a Bayesian network that integrates these two strands...
Article
Full-text available
In this study, we combine reconstructions of volcanological data sets and inputs from a structured expert judgment to produce a first long-term probability map for vent opening location for the next Plinian or sub-Plinian eruption of Somma-Vesuvio. In the past, the volcano has exhibited significant spatial variability in vent location; this can exe...
Article
Full-text available
This study presents new and revised data sets about the spatial distribution of past volcanic vents, eruptive fissures and regional/local structures of the Somma-Vesuvio volcanic system (Italy). The innovative features of the study are the identification and quantification of important sources of uncertainty affecting interpretations of the data se...
Article
Fig. 1. Fragility curve for a hypothetical 4-state damage scale ranging from no damage to structural collapse.
Chapter
An overview of the use of expert elicitation and its application to science issues in siting facilities for geological disposal of nuclear waste, including the 'Topaz' project, investigating long-term tectonic hazards with relation to siting a geological disposal facility for radioactive waste in Japan.
Article
Full-text available
Scour (localised erosion) during flood events is one of the most important threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important for many infrastructure owners, and is supported by industry guidance...
Article
A high degree of uncertainty exists for chronic wasting disease (CWD) transmission factors in farmed and wild cervids. Evaluating the factors is important as it helps to inform future risk management strategies. Expert opinion is often used to assist decision making in a number of health, science, and technology domains where data may be sparse or...
Article
ABSTARCT Chronic wasting disease (CWD) is a neurodegenerative, protein misfolding disease affecting cervids in North America in epidemic proportions. While the existence of CWD has been known for more than 40 years, risk management efforts to date have not been able to curtail the spread of this condition. An expert elicitation exercise was carried...
Article
Full-text available
We clarify key aspects of the evaluation, by de Vries and van de Wal (2015), of our expert elicitation paper on the contributions of ice sheet melting to sea level rise due to future global temperature rise scenarios (Bamber and Aspinall 2013), and extend the conversation with further analysis of their proposed approach for combining expert uncerta...
Article
Full-text available
A key question for volcanic hazard assessment is the extent to which information can be exchanged between volcanoes. This question is particularly pertinent to hazard forecasting for dome-building volcanoes, where effusive activity may persist for years to decades, and may be punctuated by periods of repose, and sudden explosive activity. Here we r...
Article
Full-text available
Based on rapid analyses done in near real-time and in support of scientific advice, I present two cases of prima facie evidence for an earth tide triggering effect on earthquake activity during two volcanic eruption episodes: the first, in relation to large magnitude earthquakes, occurred during August 2014 in the 2014 − 2015 Bárðarbunga-Holuhruan,...