Urban resilience against disasters represents a key issue for contemporary society. The increasing complexity of cities along with more severe threats induced by climate change is pressing modern societies to search for new paths to prevention, preparedness and rapid recovery. As a result, resilience is triggering an increasing interest within many scientific contexts to explore the capabilities of communities to withstand extreme events. The present study proposes a framework aimed at quantifying disaster resilience of urban systems while ensuring an adequate level of sustainability, all according to a social and human-centric perspective. Urban networks are modelled as hybrid social–physical networks (HSPNs) by merging both physical and social components, and engineering measures are performed on HSPNs, as a measure of urban efficiency, within a multi-scale approach. Thence, social indicators are identified in order to characterise quality of life in the aftermath of a catastrophic event. Both efficiency and quality of life indicators are evaluated using a time–discrete approach before and after an extreme event occurs and during the recovery phase in order to measure inhabitant happiness and environmental sustainability. This approach allows handling different kinds of information simultaneously, being potentially implemented both in peacetime and during the recovery process. The former can be effective for urban coping capacity assessment in order to reduce risks as a mitigation instrument. The latter can be used in the post-event to identify the best recovery paths needing to be followed for adaptation. © 2015, Springer Science+Business Media Dordrecht

Abstract:The concept of resilience is used in multiple scientific contexts, being understood according to several different perspectives. Essentially, resilience identifies the capability to recover, absorb shocks, and restore equilibrium after a perturbation. Recently, resilience is triggering increasing interest in engineering contexts, referring to communities and urban networked systems, as the capability to recover from natural disasters. The approach to the engineering resilience dates back to the early 1980s, when Timmerman defined resilience as "the ability of human communities to withstand external shocks or perturbations to their infrastructure and to recover from such perturbations". In this paper, a literature review of the existing methodologies to quantify urban resilience is presented according to a civil engineering perspective. Different approaches, for diverse applications, are examined and discussed. A particular focus is done on the studies from Cavallaro et al. and Bozza et al., approaching disaster resilience of urban environments to natural hazards according to the complex networks theory.

People living in a city represent the most important agents of the urban system. In fact, people organize bits of the city, while organizing their own lives, hence directly influencing much of the city structure, from both a human point of view and a topological one. Such a self-organizing process reflects on both safety and life quality of citizens and efficiency of city services. As a result, in order to better manage a city one should know its inhabitants' behaviour and its topological configuration too. An ambitious goal that can be pursued in the sense of complex networks theory approach, studying the urban centre as a hybrid social-physical network made by both human and physical components (HSPN) [1]. In this study different topological structures and geometric shapes of cities are investigated, focusing on the efficiency of cities themselves, and their resilience. Moreover, due to the current increasing risk of natural and human-induced disaster threatening local communities, urban societies are suffering a gradual reduction of their actual and potential resilience, as their ability to cope and withstand with external events. To this purpose, seismic events are simulated for each investigated urban geometry, referring to the most common shapes existing worldwide. A novel systemic measure of the expected damage state is here defined, which allows for a vectorial measure of the city efficiency in its entirety. Urban resilience is assessed as an integral measure, before, during and after an extreme event occurs. Thence, a recovery strategy is hypothesized and the efficiency of the HSPN network and the resilience of the city are then evaluated and compared in a timediscrete analysis. 1513 1514

Prompt and efficient responses against natural hazards are needed to build cities capable of withstanding disasters, namely resilient cities. This study aims at presenting and testing synthetic resilience indices over a real urban center threatened by multiple hazards, for which a global overview of city performance is requested. An integrated framework is proposed for quantitative resilience assessment by way of time‐independent synthetic indices. The approach proposed is in accordance to the complex network theory and uses a global indicator of the system connectivity to assess the city functioning also in case of network disruption. Resilience is evaluated as a proxy for systemic urban damage by modeling a city ecosystem as a hybrid social–physical network. Seismic and landslide scenario analyses are performed for the city of Sarno, Italy. A probability‐based approach is used to compute urban vulnerability. Subsequently, to highlight changes in results according to the type of disaster, a recovery strategy is simulated to assess efficiency and damage states in each recovery stage, and urban resilience.

Resilience represents a key issue for modern societies. Resilience is related to sustainability as safeguarding environmental assets can reduce risk and provide resources to facilitate recovery. The methodology quantifies the disaster resilience of city ecosystems by measuring urban efficiency in the event of shocks, according to an anthropocentric perspective. Cities are modelled as hybrid social–physical networks (HSPNs), accounting for interrelations between the physical and social components. Seismic scenarios are run on diverse urban shapes and on the real case study of the city of Sarno. Results on synthetic HSPNs show consistency with the real case study, therefore the validity of the model is highlighted. Urban shapes or forms prove to have a significant impact on urban efficiency in terms of service delivery, and on urban disaster resilience. The methodology proposed in this paper could be a useful tool for urban planners, particularly in cities with high exposure to natural disasters