Multi-hazard analysis across Italy and New Zealand
A bit about me
I was born and raised in Italy, where after a Liceo Classico (all about literature, philosophy, art and science), I acquired an interest in numbers and in understanding phenomena through them. This led me to Milan, where I obtained a Bachelor’s degree in Statistics and Economics, and a Master’s in Actuarial Sciences.
I first learnt about natural hazards through studying risk theory and insurance regulation, but the financial aspect of those subjects was proving a limit to my growing interest. Hence, I moved to Palmerston North, to begin a PhD in Statistics at Massey University. There I am mentored by Professor Mark Bebbington, Professor Geoff Jones and Doctor Xun Xiao, who are guiding me in the process of expanding my knowledge and my skills in order to better understand natural hazards.
My project focuses on the interactions between natural hazards, aiming to understand how the interaction of events occurring in the same space and within a suitable time window can affect the occurrence of secondary (triggered) events. An example of that is the chain of events I am working on, which is composed of earthquake and rainfall triggered landslides. While both seismic events and precipitation can affect the occurrence of landslides, the interaction of these two primary events is highly nonlinear, and has highly significant effects on the frequency of landslides in major events. The Kaikōura earthquake and its aftermath is a clear example of this.
Therefore, I have built a statistical model capable of embracing the characteristics of primary events to evaluate their effect on secondary ones. Large, multiyear landslide data is scarce, but I was able to obtain perhaps the most complete data set, from the Italian region of Emilia Romagna (Italy and New Zealand are quite similar!). I have developed and validated the model on this data set, but it can be applied in New Zealand, and anywhere else in the World.
In this moment, I am working on extending the model to include landslide dams. These are a not unusual phenomenon which occurs when a landslide falls on a river, blocking it and forming a dam. The dams often fail catastrophically, releasing a flash flood with great destructive potential. A quantitative estimation of the survival time of the dam is crucial in order to give authorities as much information as possible so that they can make informed decisions and take prompt actions.
Power and participation in disaster risk reduction: A case study in Franz Josef
A bit about me
My interest in disasters started after I finished a BA/BSc conjoint degree at The University of Auckland, when I had the chance to complete a summer studentship working on participatory disaster risk reduction in the Philippines. Since then, I have had the opportunity to work with different non-governmental organisations in Asia and the Pacific on projects based around people’s participation in reducing disaster risk. My work focused on fostering children’s participation and developing participatory tools. These experiences allowed me to combine my love of travel with developing my interest and knowledge in the field of disasters.
After I returned to The University of Auckland and completed an honours degree in geography, I was given the exciting opportunity to get involved with the Resilience to Nature’s Challenges National Science Challenge. The work is allowing me to apply the knowledge and lessons I learnt in international contexts to people’s participation in reducing the impact of disasters in New Zealand.
Outside of my PhD, I like to spend my free time with friends and family going on outdoor adventures such as hiking, diving, and camping.
My PhD research is looking at the different initiatives being undertaken by and with residents of Franz Josef to reduce the risk posed by the many natural hazards threatening the township. Using ethnographic research methods, it is attempting to understand how participatory processes are experienced and navigated by local and outside stakeholders, and by those facilitating them. It is particularly focusing on how power and power relations condition participation and its outputs, as well as how they enable or inhibit processes and outcomes that are conducive to building resilience and reducing disaster risk.
I am also attempting to include a participatory research component in my thesis, to incorporate the knowledge, ideas and views of some of Franz Josef’s residents. Spending time living in the Franz Josef township on the beautiful West Coast and getting to know its residents has been the highlight of the process so far!
Stopbanks alongside Franz Josef Township
People’s participation is crucial to effectively and efficiently reducing the impact of disasters. However, there are gaps between the theory and rhetoric of participation, and what most often plays out in practice. Various projects and initiatives operate under the term ‘participation’ in disaster risk reduction that in reality are standardised, top-down approaches that have little interaction with formal decision making. They act to perpetuate existing power relations and structures within decision making processes, rather than dissolve them. They can also undermine local efforts to reduce disaster risk. Such approaches often result from the failure to adequately acknowledge, analyse and accommodate power and power relations.
This project aims to change the way we think about power and power relations in participatory literature and practice. I hope that in doing that my research will contribute to the knowledge base needed to improve both the theory and practice of creating meaningful processes where people can contribute towards decision making around reducing disaster risk in New Zealand.
Using graphs for good: Modelling multi-hazard impact scenarios to better inform communities and emergency services
By Alex Dunant
An earthquake or eruption alone can be devastating, and to make matters worse natural hazard events rarely happen in isolation. An earthquake might trigger a landslide which blocks part of a river, eventually causing a dambreak flood. This cascade is an example of a multi-hazard event.
Unfortunately, it is hard to quantify the dynamic interactions that cause these phenomena, meaning that we don’t have a good understanding of how multi-hazard events will play out. This is a problem, as groups like communities and emergency management service providers need to know the risks involved in order to prepare. If we don’t consider the complex nature of natural catastrophes we will likely underestimate the hazard risk in any given area, leading to increased vulnerability and distorted emergency management priorities.
In light of this, PhD researcher Alex Dunant is investigating how we can map out the interaction of hazards. He is combining this mapping with iterative computation to create potential multi-hazard scenarios threatening parts of New Zealand.
Alex is part of the Resilience to Nature’s Challenges Hazard research programme, and is using data from the 2016 Kaikōura earthquake to illustrate his novel method of multi-hazard simulation. Basically, Alex is using the ‘hazard footprints’ in an area, which show the impact any one hazard will have, to build a hazard network. This network shows, using arrows, the relationships between each of the individual hazards. Then, using the network he can build iterative disaster scenarios, which show, using mathematical calculations, the propagation of a hazard cascade. These three processes are shown below.
In order to set this novel method, Alex is using the 2016 Kaikōura earthquake event and its recorded impacts as a calibrating point to study the cascading events. The method is tested by assessing the compounded impact of earthquakes, rainfall & landslides on the road system.
It is hoped that this research will give communities and emergency service providers a better idea of the spectrum of natural hazard risks in their area. This knowledge will enable them to better plan and prepare for a hazard event, ensuring their emergency management priorities line up with local risk.
Alex is due to finish his PhD in 2020, while also working part-time in GNS Science’s Risk and Society group. He plans to use his novel method to study the potential multi-hazard impacts for Franz Josef, while also adding complexity to the model. In addition, Alex has created a tool for regional landslide dam assessment and potential outburst flood, which will be useful in modelling risk for Franz Josef as the township sits beside the Callery Gorge and would be vulnerable to flooding. Alex is also hoping to further develop impact assessment methods and other innovative ideas to help us to better plan for natural disasters.
Franz Josef: Developing resilience in a community at risk
By Tim Davies
The small township of Franz Josef Glacier is located in Westland, half-way down the west coast of the South Island. Originally built on farming and forestry, the township’s dominant industry is now tourism, with visitors drawn from all corners of the globe by the area’s beautiful, dramatic landscape. The sharp peaks and valleys that make the area so attractive are a result of the landscape being very dynamic – its striking beauty was shaped by the earthquakes, landslides and floods that have occurred since New Zealand first rose above the ocean. These events will continue to occur in the future, and thus threaten human society with a wide range of hazards. Franz Josef, like much of Westland, is vulnerable to a range of hazard events including earthquake, flood, landslide and rockfall, and as a result the community needs to ensure it is resilient enough to live through, and prosper after, any future major hazard event.
Why is the area so risky?
Franz Josef is built right on top of the Alpine Fault. This is a fault line that runs for about 600 km along the west of the South Island, and has a history of producing a magnitude 8 or greater earthquakes a few times every millennium. When the Alpine Fault next ruptures the township is likely to be severely affected by ground rupture, intense and prolonged ground shaking and rockfall/landsliding from the adjacent steep slopes. But worse could be to come after the shaking has finished; hazard events like earthquakes rarely happen in isolation. Any major west coast earthquake would certainly trigger many large landslides, one of which could block the adjacent Callery Gorge. If large enough, this would cause a landslide dam, resulting in river water building up behind the slip. Once overtopped the dam would very likely fail, suddenly flooding the already reeling Franz Josef community. Over the following decades, the dam sediment would cause ongoing river sedimentation and flooding. This “hazard cascade” scenario is obviously catastrophic, but by no means fanciful; similar dambreaks and sedimentation were devastating in China after the 2008 Wenchuan earthquake, and a classic dambreak event occurred in the nearby Poerua River in 1999. In reality, moreover, many different scenarios are possible; a range of hazards might occur in any number of combinations, with the inevitable severe aftershocks potentially causing multiple landslides, ground collapses or tsunami in the years following the main shock.
In order to be able to prepare for and increase resilience to the impacts of this wide array of natural hazards, it is important first that we know as much as possible about them. This is what a research team within the Resilience to Nature’s Challenges Hazard Toolbox is doing. By collating available hazard information and engaging with the community, the team has been working to increase understanding of the hazards in the area, and the effects that they might have. A wide range of previous studies has been collated to develop a comprehensive “hazard-scape” for Franz Josef (Fig. 1), forming the basis for working with the community and officials to develop the “impact-scape” for the area. This illustrates the range of hazard event impacts to which the community needs to increase its resilience.
Modelling potential hazard impact scenarios
One of the projects that is currently underway involves developing a simulation model that will examine all the possible combinations and cascades of hazards affecting the town’s societal assets. PhD student Alex Dunant is building the model based on graph theory, and it will shed light on the complex hazard-impact interactions that can occur in the area. The information produced by the model will give communities, officials and service providers a better idea of the spatial and temporal distribution of impacts, and their societal consequences, enabling them to make more informed decisions about planning to reduce future impacts, and about emergency management priorities . You can find out more about Alex’s work here; Figs 2, 3 and 4 come from his work, which is using the hazards that affected the Kaikoura area after the2016 earthquake to test his Franz Josef model.
Advance planning to reduce impact
As well as developing multi-hazard-impact scenarios, the Hazard Toolbox team is also undertaking research to find out what actions and measures are required to improve the Franz Josef community’s resilience; that is, to reduce the impacts on the community of the next severe hazard event, whether it be earthquake, landslide or flood. As well as possible deaths, injuries, damage and disruption, these impacts include loss of power, communications and road access, all of which would significantly reduce the township’s ability to function even if it suffered only slightly from direct hazard impacts.
In parallel to this work, environmental and engineering consultants Tonkin + Taylor were commissioned by the West Coast Regional Council in 2017 to investigate the township’s options for increasing its resilience to natural hazards, making use of the Hazard team’s information. Three options have been developed with and presented to the Franz Josef community, each offering a different level of resilience, at a different cost. The first option has the lowest initial cost, but highest risk, in which the community would stay where it was and continue to defend itself from flooding by continuing to increase stopbank height. This is the least disruptive option, involving no relocation of homes or infrastructure, but it also has the least impact on resilience, with the entire township remaining vulnerable to the impacts of a wide array of hazards. It also includes an ongoing increase in dependence on river stopbanks that are susceptible to earthquake-induced collapse. The second option sees some of the township’s integral buildings and infrastructure being moved out of the high-risk area, while some of the community stays in its current location. This would reduce (but not eliminate) risks due to flooding, earthquakes and rockfall/landslide. The final option is the costliest, but also provides the greatest level of resilience to the Franz Josef community. It would involve moving the entire township several kilometres, away from the high-risk area. While this would permanently mitigate almost all of the current risk, it is the most disruptive option, requiring upheaval of homes and businesses, and abandonment of an area that has been occupied for generations. It also requires the highest up-front cost; however the benefits would continue to accrue in perpetuity. The full report on these options can be found here
Choosing among these three options is no easy task, and even with a relatively small population of fewer than 400 residents, reaching a stakeholder consensus in Franz Josef will likely be difficult. Another Hazard Toolbox PhD student, Kat Hore, is currently living for extended periods in Franz Josef to study the societal interactions and power structures that affect such a significant decision-making process. Kat is assessing the extent to which the consultation processes enable or deter genuine participation of local people in decision-making. You can find out more about Kat’s work here.
Researchers in the Hazard Toolbox team have been working closely with the Franz Josef community, Regional and District Councils, Civil Defence Emergency Management Groups and lifelines/infrastructure organisations over the past three years, and will continue to do so in the future. This close collaboration fosters communication and trust among the individuals involved, and facilitates input and ownership by all stakeholders. It also ensures that research is steered in a direction that will produce tangible, useful results that will benefit the local community and stakeholders.
The next steps for this research project involve completing the multi-hazard impact scenarios for Franz Josef, which will provide a sounder basis for decision-making than presently exists. The framework that Alex Dunant is developing for hazard and impact scenarios also has the potential to incorporate societal information, and to simulate the ongoing interactions and feedbacks between societal and infrastructural systems following a disaster, allowing presently unforeseeable situations to be identified and planned for. The outcome of Kat Hore’s embedment within the Franz Josef community during this critical time will provide much clearer understanding of how a community weighs up the wide range of hazard, impact and disruption information relating to future events, while at the same time maintaining its everyday societal and commercial functions in a dynamic political and economic environment. It will also provide insights on the approaches taken by various stakeholders to foster the participation of Franz Josef residents in creating knowledge and decision making processes.
The defining characteristic of the Hazard toolbox team’s research is the drive to make science and planning effective within a real-life context, by involvement with a community facing critical decisions about its future sustainability in the midst of a dynamic landscape. This context severely tests the ability of science to generate information that is both relevant and useful to those most threatened by future disaster events.
The beautiful mountain ranges and spectacular scenery of New Zealand’s South Island can be largely attributed to the many active fault lines running through the island. When these move, in occasional response to the inexorable creep of the Pacific and Australian tectonic plates, the landscape changes shape, and over millions of years this has given us our visually stunning landscape. However, the process is ongoing, and every now and then an earthquake changes the landscape again.
One of the largest of these faults is the Alpine Fault, which runs along the west coast of the South Island; it marks the currently-locked boundary between the Australian and Pacific tectonic plates, and the long-term displacement along this boundary has given rise to the Southern Alps. This fault carries most of the island’s plate boundary strain, and as a result it has a long history of ruptures, several each millennium, each producing a magnitude 8 or so earthquake. The next quake of this size will have devastating consequences for much of New Zealand’s South Island, and flow-on affects for the entire country. In light of this, a South Island-wide Alpine Fault earthquake planning initiative has been developed. Led by the six South Island Civil Defence Groups and co-funded by the Ministry of Civil Defence, Project AF8 is developing a scenario-based response plan for the seven days following the earthquake, based on the latest research in earthquake science. Find out more about Project AF8 here.
Researchers in the Resilience to Nature’s Challenges Hazard Toolbox have been working to extend Project AF8’s 7-day hazard impact scenario out to 10 years post-quake, in order to assess the longer-term impacts that may constrain response to and recovery from the event. Known as the AF8+ Scenario, this project is developing an understanding of the several different impacts – some long-term – that will affect assets and infrastructure after the quake, and their subsequent recovery over the decade that follows. The AF8+ scenario differs from AF8 itself in having a more realistic aftershock (Fig. 1) and landslide sequence, because AF8 had aftershocks and major landslides within the 7 days in each CDEM Group area. It also has a realistic post-quake weather sequence, identical to the 2006 – 2016 weather sequence, whereas the AF8 scenario had a 50-year storm 3 days after the mainshock.
The use of scenarios to inform planning for future events is becoming common worldwide, as a complement to disaster risk reduction. A scenario has no probabilistic component, meaning it can be understood by non-technical personnel and all stakeholders can be equally informed in contributing to planning for impact reduction. Nevertheless, it is important to note that a scenario does not represent what will happen in the future – it is a good example of the sort of thing that can happen. Hazards impact societal functioning by causing things like isolation, loss of lifeline services, deaths and injuries, and these effects don’t depend critically on the exact type or intensity of hazard event. Communities need to develop resilience to these hazard impacts, not to the hazards themselves. Thus the scenario is simply one of many starting-points for developing knowledge about societal impacts, and its specific details should not be the focus.
What would be affected?
A magnitude 8 quake along the Alpine Fault (or on any other major fault or combination of faults) will have direct effects on infrastructure networks throughout the South Island. For example, ground shaking can damage electrical substations and powerlines throughout the island. In addition, as seen in the 2016 Kaikōura quake, the earthquake will trigger landslides that block and damage roads, railway lines and other transport infrastructure such as bridges and tunnels. These landslides may also generate tsunami if they fall into lakes or fiords. In the longer term, aftershocks will continue to disrupt recovery work. Earthquakes and landslides will deposit large amounts of sediment into waterways, and the effects of this appear likely to continue for decades – well beyond the timescale even of AF8+. This latter aspect is being explored in Jess Blagen’s University of Canterbury PhD, involving a dendrochronological study of aggradation pulses on the West Coast lowlands over the last 1000 years.
When one fails, others are cut off too
One of the major considerations in response to the AF8+ scenario is the interdependent nature of infrastructure networks. If one network is knocked out, others are often disrupted too. For example, if transport infrastructure in an area is damaged, repair of other infrastructure will likely be delayed as maintenance crews aren’t able to get to the water pump station or telecommunication tower to fix it. This interdependence can compound the effect of a hazard event, as infrastructure network failures, like natural hazards, can occur in cascading fashion, which in turn hinders and complicates recovery of those systems. The AF8+ scenario, in conjunction with the National Interdependent Infrastructure model, will shed light on the complex interactions that can take place within and between both types of network, and model the recovery process. Ali Davies’ PhD at University of Canterbury has focussed on working with infrastructure providers and the Franz Josef community to relate post-quake community needs to post-quake levels of service.
Keeping the lights on
One of the focus areas for the AF8+ scenario’s work is electricity infrastructure. Almost every other infrastructure network relies on electricity to function, meaning prolonged and widespread power outages would have significant impacts on response and recovery across the board. The AF8+ scenario is being used to assess a new electricity resilience framework, including the development of new methods to manage the power system that will allow for its rapid restoration if (or when) major parts of the West Coast are cut off.
The scientist – community – practitioner collaboration
The outcomes of this project will be used to guide recovery planning for a large earthquake event in the South Island. Based on experience gained during AF8, the extended AF8+ scenario will provide a basis for the development of long-term resilience-focussed collaborations between Civil Defence, lifeline organizations, communities and scientists both on the West Coast and across the South Island. This in turn will provide a tested model for the rest of New Zealand, which can be exported to the world.
Once completed, the AF8+ scenario will help to guide and assess pre- and post- event investment decisions. Having a broad understanding of the likely nature and duration of hazard impacts allows all groups within society (officials, infrastructure providers, emergency managers, civil and commercial organisations and communities) to assess the impacts that the AF8 event and its natural system consequences will have on them, and start to develop plans for both reducing the severity of the impacts by pre-adaptation, and for managing the impacts better when they do occur.