To grasp specific population distribution information is crucial for accurate impact assessments and preparedness planning on natural disasters. With the high popularization of mobile phones, it is possible to know the distribution trend of the people movement in different regions. The mobile phone data from Chunghwa Telecom (the telecommunications company with largest market share in Taiwan) displayed in 500m×500m grids gives the spatiotemporal distribution of people around the Taiwan area on the geographic information system (GIS). Combined with immediate reception of earthquake intensity distribution map, not only can the number of people at risk be more accurately estimated, but also the abnormal flow of people can be highlighted in areas, and then provide real-time warning messages. Except for the real-time crowd data, the historical data from one year of 2018, which is converted into weekly crowd data, are also provided for the purpose of seismic disaster scenarios to improve the precision of relief needs by the grid-base earthquake impact assessment technology of TERIA (Taiwan Earthquake Impact Research and Information Application Platform, established by NCDR) for enhancing the disaster resilience against future major earthquakes.

How to cite: Liu, S.-Y. and Huang, M.-W.: Applying Mobile Phone Data on Seismic Disaster Reduction, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3045, https://doi.org/10.5194/egusphere-egu24-3045, 2024.

Understanding the complexity of past chain events in depth and learning from them to improve
decision-making in a dynamic context can be challenging. Although efforts have been made to
address these challenges, further research is needed. Storylines have proven to be a valuable
qualitative tool not only for describing multi-hazard scenarios, understanding the system and
the interrelationships between different elements, but also for improving resilience by taking
into account lessons learned throughout the process.

The 2021 La Palma volcanic eruption, with its enduring aftermath characterised by atmospheric
gas emissions in one of the island's prime tourist locales, exemplifies the intricate challenges in
decision-making for planning, procedural execution, and organisational management. This
event highlights the extensive and profound impacts of such dynamic risks, underscoring the
need for adaptable and robust strategies in risk management and response. Our study aims to
provide a comprehensive understanding of the whole volcanic disaster in detail by integrating
the different dimensions (multi-hazard, multi-risk and systemic impacts) into the disaster risk
reduction cycle (prevention and preparedness, response and recovery). This approach provides
a holistic and proactive approach and allows for an assessment of the impact and
consequences of the decision making process in the Canary Islands at each stage over time. For
this purpose, a 20-year timeline will be used, starting in 2004 when the first seismic swarm
indicated a possible volcanic eruption in the island of Tenerife.

This research uncovers a significant shortfall in risk planning across all stages of the disaster
reduction cycle on the islands, noting a disproportionate emphasis on administrative
coordination during emergencies. The absence of preemptive measures in land-use planning,
especially in areas highly vulnerable to exposure, exacerbates the complexity of post-eruption
recovery. By thoroughly examining the decision-making processes, planning strategies, and
organisational procedures, this study aims to distil key lessons from recent experiences. Such
an endeavour enhances our comprehension of the complex interplay between decisions and
risks, providing critical insights for bolstering resilience against volcanic disasters.

How to cite: García-Vaquero, M., García-González, S., Padrón-Fumero, N., Crummy, J., Febles-Arévalo, T., and Díaz_Pacheco, J.: A holistic examination of Disaster Risk Management in the context of volcanic risk in the Canary Islands, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18933, https://doi.org/10.5194/egusphere-egu24-18933, 2024.

Landslides cause severe impacts on society, infrastructure, and the environment globally, and their occurrence in some regions is expected to rise due to climate change. Although the cumulative impacts of landslides do not reach the level of earthquakes or floods, their disperse occurrence in space and difficult prediction pose a fundamental challenge for landslide disaster risk reduction effort. Clearly, accurate information is needed both for understanding spatiotemporal occurrence of landslides and their social impacts and responses held by societies. Documentary data are among the key sources that enable compilation of regional landslide databases, allow to quantify the landslide impacts and describe both quantitatively and qualitatively causal chains leading to increased landslide risk and the societal responses to landslide events. In this respect, the documentary data fill the time gap between the landslide occurrence in the past environments studied by proxy data, and the present-day landslides, for which different monitoring and mapping techniques may be used. Over the last decades, important progress has been made in employing various documentary data for landslide research, and extending empirical evidence about advantages and limitations is available thanks to case studies from different environmental and institutional settings. The synthesis of this progress that would guide further research is missing though. The overall goal of this paper is to broaden the perspective on the use of documentary data in historical landslide research, which has so far too much concentrated around the landslide inventories. To do so, we present a scoping literature review with three main objectives. First, we present a classification of both quantitative and qualitative approaches and related research questions in historical landslide research, linking them to key challenges in landslide disaster risk reduction. Second, we review the types and content of available documentary data sources with special attention paid to sources that have been underresearched so far. Finally, we review the quantitative and qualitative methods used to analyse the content of documentary data. While doing so, we draw also from comparative evidence in historical climatology and hydrology in order to point to methods that may hold a potential, but have not been validated in landslide research yet. The paper concludes with identifying challenges and pathways for future research.  

How to cite: Raška, P.: Recent progress in the use of documentary data in landslide research: a review of approaches, sources, and methods , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20289, https://doi.org/10.5194/egusphere-egu24-20289, 2024.

From the perspective of natural disaster prevention, larger-scale and higher-intensity geomorphic events often have longer recurrence intervals. The impact of these events on a region is frequently underestimated unless residents have experienced them firsthand. Consequently, the success of promoting self-reliant disaster-prepared communities by the government heavily relies on the experiences of the affected population. In this context, our study integrates government cartographic data and interprets the geomorphic evidence preserved in the landscape.

We conducted in-depth interviews with elders from indigenous tribes, leveraging their rich storytelling tradition and local residents' experiences to collect observations of environmental changes, past disaster experiences, and ancestral stories. The spirit of storytelling is incorporated into the map user manual, emphasizing a place-based approach. Using the devastating impact of Typhoon Morakot in 2009 on the Tjalja'avus Tribe in southern Taiwan as a case study, we produced a geomorphological hazard thematic map of the tribe. This map utilized national environmental mapping imagery, including landslide records, large-scale landslide-prone areas, potential debris flow streams, and high-resolution digital elevation models created by unmanned aerial vehicles LiDAR.

Through a combination of multi-temporal data visuals, we highlighted recent (within the last five years) highly active landslide locations, emphasizing dynamic geomorphic features. In the context of environmental awareness and risk communication between the government and local communities, we structured the map user manual to revolve around the narrative axis of visible terrain features in the tribal landscape and experiences or stories related to soil and rock disasters. This approach allows individuals to comprehend the geomorphic influences leading to disasters in their communities, facilitating collaboration between the government and community builders. Ultimately, our initiative aims to achieve environmental management and disaster prevention goals within indigenous communities.

How to cite: Lin, S.-C., Shen, S.-M., Wang, S., Yua, M.-T., Lin, S.-C., and Chang, C.-H.: Revealing Environmental Threats: Harmonizing Indigenous Narratives with Geomorphic Hazard Thematic Maps for Community Awareness, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18132, https://doi.org/10.5194/egusphere-egu24-18132, 2024.

Here we present the project activities of an ongoing project aiming at the identification of potential failure modes of dams and the development of the methodology to be applied on water management dams in Slovenia. Water is the most important natural resource for human existence, while changes in hydrological conditions have an impact on the water balance and require innovative approaches in water management. There are currently 68 registered infrastructure facilities in Slovenia, 42 of which meet the criteria of large dams or are subject to a special regime for operational safety as critical infrastructure. According to the Slovenian National Committee for Large Dams the average age of our dams is already more than 45 years.

Objectives of the project proposal, which will last 24 months, are the following: the analysis of the current state of the practice in the field of dam surveillance in Slovenia, provision of a summary document with a set of potential failure mechanisms for each type of dams, and development of a methodology for identifying failure mechanisms and monitoring the condition of dams. Monitoring of dams is regularly carried out in Slovenia, at least in the form of technical monitoring of the structures. However, we must note that professional knowledge of the operational safety of dams has advanced considerably since the time when most of the dams in Slovenia were built. In particular, the understanding of dam safety has changed and is now understood in a broader sense, encompassing the safety of the dam and auxiliary structures under all conditions throughout its life cycle, as well as the safety of the population and the environment in the dams' impact area. The lifetime of dams is very long, and sound structural management improves their structural health of dams and extends their service life.

The main output of the project is the development of the methodology for identification of potential failure modes. The steps of the methodology will also be implemented on at least 3 pilot cases and will be presented to the professional public and to institutions working in the field of dams and dam engineering. The project addresses both the World Declaration on Dam Safety, (Porto, 2019), and the World Declaration Water Storage for Sustainable Development, from (Kyoto, 2012). The authors acknowledge that the research is financially supported by the Slovenian Research and Innovation Agency research project No. V2-2340 and by the Ministry of Natural Resources and Spatial Planning.

How to cite: Klun, M., Begelj, Ž., and Kryžanowski, A.: Development of the Methodology to Identify Potential Modes of Dam Failure and to Estimate Structural Health of Water Management Dams, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-3851, https://doi.org/10.5194/egusphere-egu24-3851, 2024.

The Central American Dry Corridor (CADC) spans Guatemala, Honduras, El Salvador, Costa Rica, and Nicaragua. Over half of the population in this region is engaged in agricultural activities, with more than 73% of the rural population living in poverty, and 7.1 million people experiencing severe food insecurity. The increasingly frequent droughts exacerbate the challenges faced by agricultural production in this area. Long-term series of agricultural drought mapping can assist agricultural planners in minimizing the impact of drought on production. Based on data from the Moderate Resolution Imaging Spectroradiometer (MODIS) spanning from 2001 to 2021, this study will utilize the Vegetation Health Index to map agricultural drought in CADC at monthly, seasonal, and interannual scales. Multi-temporal agricultural drought mapping will reveal the spatiotemporal distribution patterns of agricultural drought in CADC over the past 20 years. Additionally, the study will employ the Mann-Kendall test and Sens' slope estimator to simulate the changing trends of agricultural drought, aiming to identify regions where agricultural drought is worsening.

How to cite: Qiu, J. and Tarolli, P.: Long-term agricultural drought monitoring in the Central America Dry Corridor using Vegetation Health Index, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9901, https://doi.org/10.5194/egusphere-egu24-9901, 2024.

This paper presents a theoretical frame relying on the graph theory for assessing extreme weather events relative damage to global value chains. 
The approach is defined in three steps: the first part of the paper presents the intuition inspiring the defined model and associated theory , the second part is focused on a scenario analysis declining extreme events relative severity by countries, the third part leverages on the graph theory to translate the damages associated to these events into macro-sectorial value chains disruptions. A numerical application is then run by estimating drought global damages.
We consider damage as a score based on extreme events occurrence, calibrated in this article with historical data. Using the graph theory, we incorporate these damages to a network of countries moving from a stationary state of constant flows before a distribution of extreme events, to a modified state considering the extreme events occurrence. The spread of these production damages is modeled as a contagion applied to a network representing intermediate consumption financial flows, to assess the cumulative effect of a damage to value chains. 

How to cite: Guichoud, S., Li, L., and Dumas, P.: Propagation of climate extremes across global value chains, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-226, https://doi.org/10.5194/egusphere-egu24-226, 2024.

Recently, the frequency and severity of droughts have gradually increased due to extreme weather events and global warming. As the demand for drought management increases, field surveys and water supply are actively conducted in many countries. Given that such drought assessment and support require the consumption of labor and financial resources, the prioritization of essential agricultural areas has become a major topic for efficient decision-making in drought relief. In this study, we proposed a Principal Component Analysis (PCA) for selecting rural specialization districts across the 162 administrative regions of South Korea. Additionally, we aimed to investigate real cases of agricultural drought occurred in these regions by utilizing the survey of water supply measures derived from Ministry of Agriculture, Food and Rural Affairs. The research data comprised seven agricultural specialization factors, exemplified by agricultural workforce and infrastructure. First, we implemented singular decomposition method included in PCA process to represent the comprehensive trends of the agricultural specialization factors with maximum reflection. High value of principal component scores (PCS) estimated from PCA was interpreted as regions with high agricultural relevance. Lastly, the PCS were classified into different levels, defining top-ranking regions as rural specialization districts. Based on agricultural drought case studies from 2018 to 2021, it is expected that finding relative damage-prone areas and establishing appropriate drought responses will be feasible.

Keywords: Principal Component Analysis, Rural Specialization Districts, Agricultural Specialization Factors, Principal Components Score

Acknowledgement

This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No. RS-2023-00250239) and this research was supported by Korea Environment Industry & Technology Institute (KEITI) through Water Management Innovation Program for Drought (RS-2022-KE002032) funded by Korea Ministry of Environment.

This work was supported by the National Research Foundation of Korea(NRF) grant funded by the Korea government(MSIT) (No.NRF-2022R1A4A3032838).

How to cite: Kim, H., Cha, H., Baik, J., Park, K., and Jun, C.: Agricultural Drought Case Study in South Korea: Selection of Rural Specialization Districts based on Principal Component Analysis, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19054, https://doi.org/10.5194/egusphere-egu24-19054, 2024.

Resilience for Social Systems (R4S) is an approach to analyse the resilience of socioeconomic systems. Societies are made up of socio-economic systems which service the needs of their populations, and addressing recurrent crises and effectively building resilience requires an integrated systems approach. Where these systems are fragile and large portions of the population are socially or economically marginalized, communities are highly susceptible to external shocks and stresses; coordination among stakeholders to strengthen these systems will ultimately improve resilience and lead to resilient and inclusive development.

The R4S approach to resilience helps to understand how various system components (stakeholders, resources, regulations) interact and interconnect, as well as assessing the potential impacts from risk scenarios. In other words, when applying the R4S Approach to build resilience, the user can anticipate better how natural hazards can trigger economic shocks, how conflicts can leave people more exposed to additional shocks or stresses (e.g., an outbreak of cholera can be triggered when water, sanitation and hygiene systems are destroyed or become inaccessible), and how long-term stresses such as environmental degradation can lower agricultural productivity, weakening food security and income levels, and impacting a household’s ability to pay for health care or education.

Understanding these dynamics is critical to deliver better programming that addresses root causes of constraints rather than symptoms alone. The R4S Approach is based on best practice in Systems Thinking, Network Theory, Scenario Thinking, Social and Behaviour Change, Inclusion and Resilience approaches and provides a logical step by step process for assessing resilience of socio-economic systems.

This presentation will provide an overview of the R4S, the innovations in the assessment of complex and interlinked vulnerabilities it provides, and practical examples drawn from GOAL’s experience of conducting the assessment and implementing resilience-building strategies based on the needs and opportunities identified.

How to cite: Sneddon, A.: A systems approach for holistic resilience building, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14637, https://doi.org/10.5194/egusphere-egu24-14637, 2024.

FEMA's Hazard Mitigation Grant Program (HMGP) assisted survivors of Hurricanes Katrina and Rita, necessitating a 25% homeowner contribution for post-disaster home elevation. The federal Community Development Block Grant Disaster Recovery (CDBG-DR) program allocated $13.4 billion to Louisiana, offering $30K grants per home, aligning with HMGP needs. This study focused on elevated residential homes in a subset of Louisiana's housing data, aiming to understand the intersection of flood risk when disaggregated by frequency, vulnerable populations, and mitigation costs.

The analysis investigating the correlation between flood frequency/severity and variables such as race and ethnicity, and socioeconomic status, exploring their interconnections. Subsequently, we explored how flood risk changed both pre- and post-implementation of elevation strategies across various return periods, aiming to determine the proportional attribution of the total AAL to these different periods. Additionally, it examined the comparative flood risk before and after elevation strategies across diverse socioeconomic statuses. Finally, it analyzed the absolute benefits of elevation strategies, particularly the avoided AAL, compared with investment values and socioeconomic statuses.

The result of this study indicates that Poverty levels remain consistent across different return periods, a notable increase in Non-white population percentages with longer return periods, and a peak in Renters' percentage at floods with a return period of ≥200 years. It’s demonstrated that a substantial percentage of the total AAL is attributed to less frequent but more severe events—those occurring with return periods between 100 and 500 years, as well as those with return periods greater than 500-year. The results show inconsistencies in the Avoided AAL values across different investment levels suggest that the relationship between investment in elevation costs and Avoided AAL is not directly proportional.

The study results provide multifaceted insights, aiding in the identification of vulnerable communities and offering guidance for resource allocation decisions, and demonstrating the impact of elevation strategies. The economic analysis enhances understanding of federal mitigation investments' cost-effectiveness across diverse socio-economic statuses.

How to cite: Al Assi, A., Mostafiz, R. B., Friedland, C. J., and Hasan, F.: Flood Severity, Socio-Economic Impacts, and Elevation Strategy Effectiveness in a Subset of Louisiana Post-Hurricanes Katrina and Rita, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-13968, https://doi.org/10.5194/egusphere-egu24-13968, 2024.