The general assumptions and the most popular methods used to assess landslide hazard and for landslide risk evaluation have not changed significantly in recent decades. Some of these assumptions have conceptual weaknesses, and the methods have revealed weackneses and limitations. After an introduction on what we need to predict in order to assess landslide hazard and risk, I introduce the strategies and main methods currently used to detect and map landslides, to predict landslide populations in space and time, and to anticipate the number and size characteristics of expected landslides. For landslide detection and mapping, I consider traditional methods based on visual interpretation of aerial photography, and modern approaches that exploit visual, semi-automatic or automatic analysis of remotely sensed imagery. For spatial landslide prediction, I discuss the results of a review of classification-based statistical methods for evaluating landslide susceptibility. For temporal forecasting, drawing on a review of geographical landslide forecasting and early warning systems, I discuss short-term forecasting capabilities and their limitations. Then, I discuss the long-term landslide projections considering the impact of climate variations on landslide projections. Regarding the numerosity and size of landslides, I discuss existing statistics on the length, width, area, and volume of landslides obtained from populations of event-triggered landslides. This is followed by an analysis of the consequences of landslides. I conclude by offering recommendations on what I imagine we should do to make significant progress in our collective ability to predict the risk posed by landslide populations and to mitigate their risk. My understanding, but also my feeling and hope, is that some - perhaps many - of the recommendations are general, and may be applicable to other hazards as well.

How to cite: Guzzetti, F.: Considerations on the prediction of hazards (mainly landslides) and their consequences, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-641, https://doi.org/10.5194/egusphere-egu21-641, 2021.

The world evolves. Cities have become the most common human settlement (>50% world population is urban). They act as major centres of economic activity and innovation, but also as hubs of crucial challenges. Cities are increasingly complex systems which have to address the enhanced demand, as well as sustainability criteria (e.g. meeting the 2015 Paris Climate Agreement target). Cities are also increasingly suffering from the impact of extreme weather, which are expected to threat US$4 trillion of assets by 2030 [1].

Science evolves too. New technology (e.g. Internet of Things) and concepts (e.g. smart cities) are emerging to manage risks and develop strategies for climate mitigation and adaptation. Infrastructure plays a core role in developing urban resilience, since they underpin all the key activities and constitute the backbone of a city. When infrastructure is robust and able to adapt, the whole city becomes less vulnerable to natural disasters.

Yet urban research does not fully fulfil the need of decision-makers: existing studies are mostly silo-based (e.g. based on single disciplines), or provide little scope for a business case, or do not offer platforms of practical implementation. Also, the uptake of developed technology (which requires specific expertise) is sometimes difficulty and seen as a further barrier.

This award lecture will review the major challenges that cities are facing today, and illustrate available tools to assess impact to infrastructure, alongside adaptation and technology options. Various international case studies will be presented regarding flooding and road networks [2, 3, 4, 5].

In the future, research and practice needs to interlink to innovate urban policy for mitigating urban climate change and adapting. Cities have never had so many and powerful tools available to tackle their challenges: while there is an immense potential, its realisation is still to unfold. The next decades are critical for developing schemes that address climate and sustainability goals, which could be solely successful with the application of latest science to practical contingencies.

Reference

[1] X Bai, RJ Dawson, D Ürge-Vorsatz, GC Delgado, AS Barau, S Dhakal, et al. (2018). Six research priorities for cities and climate change. Nature 555 (7694), 23-25. https://doi.org/10.1038/d41586-018-02409-z

[2] M Pregnolato, A Ford, V Glenis, S Wilkinson, R Dawson (2017). Impact of climate change on disruption to urban transport networks from pluvial flooding. Journal of Infrastructure Systems 23 (4), 04017015. https://doi.org/10.1061/(ASCE)IS.1943-555X.0000372

[3] C Arrighi, M Pregnolato, RJ Dawson, F Castelli (2019). Preparedness against mobility disruption by floods. Science of the Total Environment 654, 1010-1022. https://doi.org/10.1016/j.scitotenv.2018.11.191

[4] C Arrighi, M Pregnolato, F Castelli (2020). Indirect flood impacts and cascade risk across interdependent linear infrastructures. Natural Hazards and Earth System Sciences Discussions, 1-18. https://doi.org/10.5194/nhess-2020-371

[5] M Pregnolato, AO Winter, D Mascarenas, AD Sen, P Bates, MR Motley (2020). Assessing flooding impact to riverine bridges: an integrated analysis. Natural Hazards and Earth System Sciences Discussions, 1-18. https://doi.org/10.5194/nhess-2020-375

How to cite: Pregnolato, M.: Infrastructure opportunities for the resilience of tomorrow’s cities, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2215, https://doi.org/10.5194/egusphere-egu21-2215, 2021.

The eruption of Mount St. Helens in 1980 exposed a large population to volcanic ash that was found to contain cristobalite – a crystalline silica polymorph and known carcinogen. This event triggered an array of epidemiological, toxicological and geochemical studies to assess the toxicity of ash, marking the birth of a new field of research. This talk will take you on an interdisciplinary journey through the work conducted since the 1980s, which has discovered both biological mechanisms in favour of volcanic ash toxicity and inherent physicochemical characteristics of ash particles that may render the silica surfaces non-toxic. A sparsity of longitudinal clinical and epidemiological studies following eruptions means that medical evidence for chronic ash pathogenicity is lacking, but other research has shown that acute exposures to volcanic ash can exacerbate existing respiratory conditions. Additionally, a multitude of techniques and protocols have been developed for rapid, eruption-specific health hazard assessment, but conducting these assessments in a crisis is very challenging. In the absence of definitive information about the harmfulness of ash, many exposed people choose to protect themselves as a precaution, or are advised to do so by agencies, so recent research has focussed on providing them with the knowledge to do that effectively. This laboratory and community-based research, involving collaborations among geoscientists, exposure scientists, social scientists, medical ethicists, agency and community representatives, has yielded critical insight into a chain of communication from researcher, through various local ‘authorities’, to the actions taken by communities. The findings have led to changes in humanitarian and individual practice and have opened up new pathways to effective uptake of evidence-based advice through co-designed informational products.

How to cite: Horwell, C.: The health hazards and impacts of volcanic ash: an interdisciplinary journey towards effective mitigation, protection and communication, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-497, https://doi.org/10.5194/egusphere-egu21-497, 2021.