Multi-hazard Environments Research Articles

Seismic Drift Estimates of Corroded Piers: A Multihazard Approach Utilizing 3D‐IDA Analysis With Time Stamps Considering Climate Change Effects

ABSTRACTThe compounding effect of seismicity, exposure to corrosion, and climate change in regions such as North America pose significant challenges for bridge design engineers, as the multihazards impact on the seismic performance of bridge structural systems remains underexplored. While drift ratio is the most widely used parameter in probabilistic seismic demand assessment, existing models predominantly concentrate on seismic intensity levels, overlooking the increase in demand and the reduced deformation capacity, both being affected by corrosion‐induced damage and climate change. Therefore, developing an evaluation framework for the multihazard seismic vulnerability of deficient bridges is an emerging priority in the field. To address this need, a methodology is proposed here that uses data collected from field inspections to quantify the accumulation of historic corrosion damage and forecast future corrosion propagation. Climate change scenarios derived from future climate forecast models are used to project the temperature and relative humidity changes up to the year 2100; the rate of reinforcement corrosion is quantified based on these scenarios. Utilizing incremental dynamic analysis (IDA) across a projected timeline, expressions are derived for the time evolution of drift demand in existing reinforced concrete circular piers over the lifetime of the bridge. By using these results, drift demand expressions are derived for different climate change scenarios. The influence of design parameters (e.g., concrete cover, chloride diffusion coefficient, and aging factor) on the drift demands is evaluated using Monte Carlo simulation. The proposed expressions serve as a benchmark for bridge engineers to study the seismic performance of bridge structures in multihazard environments.

Probabilistic dynamic resilience quantification for infrastructure systems in multi-hazard environments

Resilience has been evolving as a key criterion for infrastructure systems as it ensures the system's dynamic performance pre-, during, and post-hazard disruptions. However, estimating these performances is challenging due to system and operation complexities, and the probabilistic dynamic nature of infrastructure system. Moreover, infrastructure systems are usually exposed to multi-hazard environments, with their own probabilistic behavior, leading to additional complexity in terms of estimating the system response and, subsequently, the overall system resilience. As such, this study develops a probabilistic resilience-centric system dynamics modeling approach to quantify infrastructure dynamic resilience based on a holistic representation of infrastructure systems under multi-hazard scenarios, whereby the probabilistic natures of both the hazards and system are incorporated. Unlike the traditional resilience quantification approaches that represent system resilience by a single value calculated after the system's full recovery, the developed model focuses on tracking the temporal evolution of system resilience along the entire period of system performance deterioration and recovery. A real-world hydropower dam, as an example for infrastructure systems, in British Columbia, Canada is used as a demonstration application to show model utility in developing resilience-guided assessment plans for infrastructure systems. Overall, the developed approach empowers the decision-makers with insights into critical operational periods, the required time to reach specified resilience targets, and the efficiency of risk mitigation measures in real-time.

Increasing multi-hazard climate risk and financial and health impacts on northern homeowners.

Currently, more than half of the world's human population lives in urban areas, which are increasingly affected by climate hazards. Little is known about how multi-hazard environments affect people, especially those living in urban areas in northern latitudes. This study surveyed homeowners in Anchorage and Fairbanks, USA, Alaska's largest urban centers, to measure individual risk perceptions, mitigation response, and damages related to wildfire, surface ice hazards, and permafrost thaw. Up to one third of residents reported being affected by all three hazards, with surface ice hazards being the most widely distributed, related to an estimated $25 million in annual damages. Behavioral risk response, policy recommendations for rapidly changing urban environments, and the challenges to local governments in mitigation efforts are discussed.

A synergistic approach towards understanding flood risks over coastal multi-hazard environments: Appraisal of bivariate flood risk mapping through flood hazard, and socio-economic-cum-physical vulnerability dimensions

The dynamics of flood risk over Coastal Multi-hazard Catchments (CMC) exhibit bizarre characteristics. In these regions, flood hazards are governed by a complex interaction of multiple flood-inducing sources; varying in magnitudes, origin, and direction of propagation. Our conventional understanding of vulnerability may be obscure within these catchments. This can be attributable to the heterogeneous nature of various physical and socio-economic entities. The study proposes a comprehensive framework to quantify bivariate flood risks over a severely flood-prone region in India. The study considers flood hazards, along with vulnerabilities transpiring from (a) physical, (b) socio-economic, and (c) composite (combination of both) groups of indicators. To overcome data scarcity prevalent in CMCs, CHIRPS v2.0, a high-resolution Satellite Precipitation Product, along with other ancillary datasets, are forced to 1D2D coupled MIKE+ hydrodynamic model to simulate flood hazards. A set of 24 indicators are considered within the Shannon Entropy-cum-TOPSIS framework to derive three types of vulnerability. The marginal and compound contributions of hazard and each vulnerability type are represented through a novel concept of bivariate flood risk classifier at the village scale. We notice high and very-high flood hazards over the coastline and floodplains. An equitable influence of socio-economic vulnerability and hazards is reflected, as they cover 41 % of villages together under varied degrees of flood risks. The impacts of hazards are underscored in the presence of physical vulnerability, as the latter contributes to risks in about 72 % of villages. Composite vulnerability prevails its impact over 53 % of villages, dominating its influence on flood risks over hazards. The study delivers vital information to the global flood management community on the prudent selection of indicators, as their influence is markedly noticed on the overall flood risks. The diversified characteristics of flood risk inspire a rationalized implementation of structural and non-structural options in resource-constrained conditions.

Dynamic Resilience Quantification of Hydropower Infrastructure in Multihazard Environments

Ensuring the continued functionality of hydropower infrastructure is of the greatest importance, considering the devastating socioeconomic and environmental impacts of dam operation failures. Among the different approaches currently adopted in hydropower dam operational safety, those that are resilience-based are at the leading edge because they focus on assessing the dynamic system performance pre-, during-, and post-hazard exposures. However, the main challenge for such assessment pertains to the complexity associated with the dynamic operation simulation of hydropower dam systems that consist of several components with nonlinear interdependencies. Moreover, the infrastructure’s exposure to a multihazard environment, which may impact one or more hydropower critical system components, poses further challenges to understanding possible subsequent dam operation failure scenarios. This study develops a resilience-centric system dynamics simulation model that provides a holistic representation of hydropower dam system components to estimate the system’s dynamic resilience in multihazard environments. The study also discusses a combinatorial procedure to generate multihazard scenarios, where a primary hazard can trigger one or more subsequent hazards. Finally, an actual hydropower dam is employed to demonstrate the developed model utility in assessing the resilience of complex infrastructure under a wide range of multihazard scenarios. The proposed model provides valuable decision support tools for infrastructure systemic risk mitigation in multihazard environments—facilitating the development of effective resilience planning strategies.

Multihazard life-cycle cost optimization of active mass dampers in tall buildings

This article proposes an optimization-based-methodology for designing multiple active mass dampers (AMDs) in tall buildings in multihazard environments. A realistic cost of the AMD system is formulated as the objective-function, and the multihazard Life-Cycle-Cost (LCC) that represents the long-term hazard-related losses, is selected as the main performance-constraint. This allows joining winds and earthquakes in a single decision parameter. Additional constraints limit the dampers forces and strokes. To ensure stability of the actively controlled building, the LQR algorithm is nested within the formal optimization problem. In addition, for the first time in the context of AMDs, their masses are considered as design variables, emerging directly as an optimization output. As the LQR control law is not aimed at optimizing costs and LCC, the lower triangular matrices related to the LQR weighting matrices are used as additional design variables. Thus, their values converge throughout the optimization to optimize the formulated cost function while satisfying the constraints. As this strategy produces large-scale problems, an efficient gradient-based algorithm is developed, using the adjoint sensitivity analysis method. The framework is applied to several examples for a benchmark-building, providing consistent results. One example demonstrates that AMDs can offer similar performance to its passive TMDs counterpart, requiring a mass 40% lower.

Progressive collapse fragility of substandard and earthquake-resistant precast RC buildings

Several natural and man-made disasters have highlighted that precast reinforced concrete (RC) buildings often have insufficient levels of structural robustness, which is the last line of defence under extreme events. Even though robustness studies were originated by the progressive collapse of the Ronan Point precast RC building in 1968, such a structural feature of disaster resilience has been partially investigated in case of precast RC buildings to date. In this study, a precast RC frame structure representative of low-rise commercial buildings is analysed under different column loss scenarios, which can produce the partial or total collapse of the structural system. Two building classes are considered, namely, buildings designed only to gravity loads and buildings designed for earthquake resistance. Structural robustness is probabilistically assessed through a fragility analysis procedure, using three-dimensional fibre-based finite element models with nonlinear links simulating connections, large-displacement incremental dynamic analysis, and multiple performance limit states for damage assessment. The output of the study is threefold: (i) a detailed assessment of the effects of column loss on precast RC frame buildings, quantifying the major role of structural detailing and beam-column connections; (ii) a fragility-informed evaluation of beneficial effects of seismic detailing on structural robustness, which can drive designers in retrofitting of existing precast RC buildings and decision-makers towards prioritization-related issues; and (iii) the generation of typological fragility curves for progressive collapse risk assessment in both single- and multi-hazard environments. Progressive collapse fragility curves can be convolved with more classical fragility models describing the failure of single components (under, e.g., flow-type landslide impact, vehicle collision or blast) and hazard, to assess systemic structural risk.

Seismic safety of informally constructed reinforced concrete houses in Puerto Rico

More than 1.6 billion people worldwide live in informally constructed houses, many of which are reinforced with concrete. Patterns of past earthquake damage suggest that these homes have significant seismic vulnerabilities, endangering their occupants. The characteristics of these houses vary widely with local building practices. In addition, these vulnerabilities are potentially exacerbated by incremental construction practices and building practices that address wind/flood risk in multi-hazard environments. Yet, despite the ubiquity of this type of construction, there have not been efforts to systematically assess the seismic risks to support risk-reducing design and construction strategies. In this study, we developed a method to assess the seismic collapse capacity of informally constructed housing that accounts for local building practices and materials, quantifying the effect of building characteristics on collapse risk. We exercise the method to assess seismic performance of housing in the US. Caribbean Island of Puerto Rico, which has high seismic hazard and experiences frequent hurricanes. This analysis showed that heavy construction, often due to the addition of a second story, and the presence of an open ground story leads to a high collapse risk. Severely corroded steel bars could also worsen performance. Although houses with infill performed better than those with an open ground story, confined masonry construction techniques produced a major reduction in collapse risk when compared to infilled or open-frame construction. Infill construction with partial height walls performed very poorly. Well-built reinforced concrete column jackets and the addition of infill in open first-story bays can reduce the greater risks of open-ground-story houses. These findings, which are quantified in the results portion of this article, are intended to support the development of design and construction recommendations for safer housing.

Unified hazard models for risk assessment of transportation networks in a multi-hazard environment

Transportation networks play a vital role in the economic prosperity of modern societies. Recent hazardous events in Greece, for instance, the 2021 Crete earthquake, the 2021 Thessaly earthquakes and floods, and the heavy 2019 rainfall in Crete, have revealed the vulnerability of roadway networks to natural hazards, resulting in severe physical damage and important economic and societal losses. Severe damage on bridges and tunnels of roadway networks is commonly related to the effects of multiple hazards that may act independently during their life span. However, the literature on risk assessment of the above elements commonly focuses on the effects of a single hazard, disregarding the effects of various hazards in a multi-hazard environment. In this context, there is an increasing need for a reasonable and practical evaluation of the multi-hazard risk of transportation infrastructure. Research project INFRARES (https://www.infrares.gr/) aspires to gain further insight into the risk and resilience assessment of bridges and tunnels subjected to independent and/or multiple subsequent natural hazards, proposing a comprehensive framework toward a more efficient risk assessment of the above critical transportation infrastructure components. This paper presents the first part of the framework. More specifically, a unified methodology for the development and graphic presentation of single seismic- and flood-hazard scenarios, as well as of novel multi-seismic-flood hazard scenarios, are presented, providing a valuable tool for risk assessment of roadway networks for separate, combined (triggered), or subsequent hazards. The unified approach followed to develop single seismic and flood hazard scenarios is initially presented. The data required to develop such scenarios are derived from recently published and freely available data accessible via European databases; hence, allowing for a straightforward application of the proposed methodology throughout Europe. The unified approach in developing single hazard scenarios is further exploited to develop integrated seismic-flood hazard scenarios. Single and multi-hazard scenarios are graphically displayed in the form of GIS format maps, with the methodology being applied to the Greek terrain for various hazard scenarios. Recent hazard events that caused significant damage to the Greek road network are also presented to emphasize the importance of proper evaluation of natural hazards and their effects on roadway networks in multi-hazard environments. The methodology developed within this study contributes toward the generation of uniform multi-hazard scenarios for the risk assessment of various structures and networks in a multi-hazard environment.

Recent Advances in Vibration Control Methods for Wind Turbine Towers

Wind power is a substantial resource to assist global efforts on the decarbonization of energy. The drive to increase capacity has led to ever-increasing blade tip heights and lightweight, slender towers. These structures are subject to a variety of environmental loads that give rise to vibrations with potentially catastrophic consequences, making the mitigation of the tower’s structural vibrations an important factor for low maintenance requirements and reduced damage risk. Recent advances in the most important vibration control methods for wind turbine towers are presented in this paper, exploring the impact of the installation environment harshness on the performance of state-of-the-art devices. An overview of the typical structural characteristics of a modern wind turbine tower is followed by a discussion of typical damages and their link to known collapse cases. Furthermore, the vibration properties of towers in harsh multi-hazard environments are presented and the typical design options are discussed. A comprehensive review of the most promising passive, active, and semi-active vibration control methods is conducted, focusing on recent advances around novel concepts and analyses of their performance under multiple environmental loads, including wind, waves, currents, and seismic excitations. The review highlights the benefits of installing structural systems in reducing the vibrational load of towers and therefore increasing their structural reliability and resilience to extreme events. It is also found that the stochastic nature of the typical tower loads remains a key issue for the design and the performance of the state-of-the-art vibration control methods.

A Comprehensive Assessment of Exposure and Vulnerabilities in Multi-Hazard Urban Environments: A Key Tool for Risk-Informed Planning Strategies

Although the increase in the frequency and intensity of disasters assigns a key role to disaster risk management in current debate on sustainable development, the efforts of national and local authorities to develop risk-informed planning strategies and increase disaster preparedness are still limited. In multi-hazard urban environments, the main criticality to support risk-informed planning strategies is the persisting lack of effective knowledge bases focused on the vulnerability of exposed assets to different hazards. Hence, this contribution, according to the first priority of the Sendai Framework for Disaster Risk Reduction—understanding disaster risk—and by tidying up methods and indicators developed in both EU research projects and scientific studies devoted to multi-risk and vulnerability assessment, aims at better using available knowledge to guide risk-informed spatial planning. In detail, an indicator-based method to carry out a comprehensive exposure and vulnerability analysis has been outlined and tested on a case study area, the multi-hazard urban area of Campi Flegrei, located in the western part of the metropolitan city of Naples in the South of Italy. The proposed method may contribute to the building up of an effective risk knowledge base, enabling planners to easily access information on exposure and vulnerabilities to different hazards, and to differently combine them into output maps capable of supporting risk- informed planning strategies.

Dilemma of the Tropics: Changes to Housing Safety Perceptions, Preferences, and Priorities in Multihazard Environments

AbstractThis study seeks to understand how housing safety perceptions have changed after a specific hazard event: the 2019–2020 earthquakes affecting the US Caribbean island of Puerto Rico. The res...

Population health risks in multi-hazard environments: action needed in the Cyclone Amphan and COVID-19 – hit Sundarbans region, India

ABSTRACT The local population of Sundarbans, an environmentally vulnerable delta region in south-eastern India, is currently affected by combined negative impacts of cyclone Amphan and the COVID-19 pandemic. The lockdown measures have created an additional burden on the health care system, while flooding during Amphan increased the risk of spreading water-borne diseases. In this viewpoint, we provide a conceptual model of the complex interlinkages among the combined multi-hazard effects, human health and water availability, with possible mitigation measures. We then discuss the specific pathways through which these immediate and long-term impacts occur and highlight the risk of together slowing progress on SDG3 and SDG6 in the Sundarbans. Finally, we call for coordinated assessment, support and appropriate intervention measures to secure clean water availability and minimize the health impacts of the recent multiple disasters in this tropical delta region.

Invited perspectives: Building sustainable and resilient communities – recommended actions for natural hazard scientists

Abstract. Reducing disaster risk is critical to securing the ambitions of the Sustainable Development Goals (SDGs), and natural hazard scientists make a key contribution to achieving this aim. Understanding Earth processes and dynamics underpins hazard analysis, which (alongside analysis of other disaster risk drivers) informs the actions required to manage and reduce disaster risk. Here we suggest how natural hazard research scientists can better contribute to the planning and development of sustainable and resilient communities through improved engagement in disaster risk reduction (DRR). Building on existing good practice, this perspective piece aims to provoke discussion in the natural hazard science community about how we can strengthen our engagement in DRR. We set out seven recommendations for enhancing the integration of natural hazard science into DRR: (i) characterise multi-hazard environments; (ii) prioritise effective, positive, long-term partnerships; (iii) understand and listen to your stakeholders; (iv) embed cultural understanding into natural hazard research; (v) ensure improved and equitable access to hazard information; (vi) champion people-centred DRR (leaving no one behind); and (vii) improve links between DRR and sustainable development. We then proceed to synthesise key actions that natural hazard scientists and research funders should consider taking to improve education, training, and research design and to strengthen institutional, financial, and policy actions. We suggest that these actions should help to strengthen the effective application of natural hazard science to reduce disaster risk. By recognising and taking steps to address the issues raised in these recommendations, we propose that the natural hazard science community can more effectively contribute to the inter-/transdisciplinary, integrated work required to improve DRR.

A PERFORMANCE-BASED COASTAL ENGINEERING FRAMEWORK

Coastal regions are exposed to both chronic and punctuated hazards, such as sea level rise and hurricane events, that can jeopardize entire coastal communities. Therefore, to effectively assess the risk and resilience of coastal communities subjected to multi-hazard environments, evaluation of the capacity of individual structures and infrastructure systems to withstand the different time-varying demands imposed in coastal settings is of paramount importance. This study proposes a comprehensive probabilistic framework for the design, risk and resilience assessment of coastal structures. The methodology also provides useful tools to inform decision-making, facilitate recovery efforts and improve resource allocation.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/8SI3Dw30yes

Mapping vulnerability: Opportunities and limitations of participatory community mapping

• Smallholders are increasingly vulnerable to multi-hazard environments. • Land management for risk reduction is under-represented in vulnerability maps. • A grounded approach illuminates socially-mediated perceptions and management. • Participatory mapping can add nuance to discussions of vulnerability, but not alone.

Crowd Behavior Simulation With Emotional Contagion in Unexpected Multihazard Situations

Numerous research efforts have been conducted to simulate the crowd movements, while relatively few of them are specifically focused on multihazard situations. In this paper, we propose a novel crowd simulation method by modeling the generation and contagion of panic emotion under multihazard circumstances. In order to depict the effect from hazards and other agents to crowd movement, we first classify hazards into different types (transient and persistent, concurrent and nonconcurrent, and static and dynamic) based on their inherent characteristics. Second, we introduce the concept of perilous field for each hazard and further transform the critical level of the field to its invoked-panic emotion. After that, we propose an emotional contagion model to simulate the evolving process of panic emotion caused by multiple hazards. Finally, we introduce an emotional reciprocal velocity obstacles (RVOs) model to simulate the crowd behaviors by augmenting the traditional RVO model with emotional contagion, which for the first time combines the emotional impact and local avoidance together. Our experimental results demonstrate that the overall approach is robust, can better generate realistic crowds and the panic emotion dynamics in a crowd. Furthermore, it is recommended that our method can be applied to various complex multihazard environments.

Risk Perception in a Multi-Hazard Environment

Summary Environmental disasters cause enormous losses of life and property every year, a threat that is recognized and addressed in both the Sendai Framework for Disaster Risk Reduction and the 2015 Sustainable Development Goals. Organizations from both the risk reduction and development fields are working to design programs that build risk understanding and risk perception to encourage protective action in communities that are often at risk from multiple, overlapping threats. We know little, however, about how individuals perceive and prioritize multiple hazards at once and how this relates to their adoption of protective action strategies in the developing world. Our work addresses environmental hazard risk perception in a multi-hazard context in eastern Uganda, with particular attention paid to the role that risk reduction and development organizations (RDOs) play in shaping risk perceptions, as well as their potential to influence protective action. To better understand risk prioritization, we used survey data from farming households to generate four indices reflecting several components of risk perception and to predict holistic risk perception through multivariate regression analysis. Our study finds that the factors shaping smallholder risk perception vary among hazards within the study population and that characteristics of both hazards and individuals are important. The regression analysis also reveals a surprising relationship between risk perception, self-efficacy, and protective action. Our findings suggest that risk reduction and development programs can play an important role in affecting both risk perception and the capacity of smallholders to respond to environmental threats. Our work adds to the growing body of literature on how people perceive and respond to risk in a multi-hazard environment, a context increasingly common in a changing world. Improved understanding of how RDO programs in the developing world are engaging with and influencing risk mitigation in the multi-hazard environments is fundamental for reducing vulnerability.

Interactions between apparently ‘primary’ weather-driven hazards and their cost

A statistical analysis of the largest weather-driven hazards in the UK contradicts the typical view that each predominates in distinct events that do not interact with those of other hazard types (i.e., are ‘primary’); this potentially has implications for any multi-hazard environments globally where some types of severe event are still thought to occur independently. By a first co-investigation of long (1884–2008) meteorological time-series and nationwide insurance losses for UK domestic houses (averaging £1.1 billion/yr), new systematic interactions within a 1 year timeframe are identified between temporally-distinct floods, winter wind storms, and shrink–swell subsidence events (P < 0.03); this increases costs by up to £0.3 billion/yr (i.e., 26%), although impacts will be spatially variable depending upon the interplay of hazards. ‘Memory’ required in the environmental system to cause these intra-annual links between event types appears to reside in soil moisture and, tentatively, sea surface temperatures. Similar, unidentified interactions between non-synchronous events are likely worldwide, and the analytical methods we have developed to identify and quantify them are suitable for application to meteorological, geological (e.g., volcanic) and cryospheric (e.g., avalanches) hazards.

Practical Resilience Metrics for Planning, Design, and Decision Making

AbstractNatural disasters in 2011 alone resulted in $366 billion (2011 US$) in direct damages and 29,782 fatalities worldwide. Storms and floods accounted for up to 70% of the 302 natural disasters worldwide, with earthquakes producing the greatest number of fatalities. Managing these risks rationally requires an appropriate definition of resilience and associated metrics. This paper provides a resilience definition that meets a set of requirements with clear relationships to reliability and risk as key relevant metrics. The resilience definition proposed is of the intension type, which is of the highest order. Resilience metrics are reviewed, and simplified ones are proposed to meet logically consistent requirements drawn from measure theory. Such metrics provide a sound basis for the development of effective decision-making tools for multihazard environments. The paper also examines recovery, with its classifications based on level, spatial, and temporal considerations. Three case studies are developed ...