Sri Lanka was the second most affected country after Indonesia, in the 2004 Boxing Day Indian Ocean tsunami (IOT). A study mission was therefore carried out twenty years after the 2004 IOT to assess the recovery of the affected regions, especially in the Eastern region of Sri Lanka, focusing on two of the most affected municipalities, i.e. Kalmunai and Batticaloa. The social and infrastructure characteristics of resettlements/relocations/new settlements in the affected regions, presence of critical infrastructure, preparedness and early warning systems installed have been assessed. It was observed that similar approaches have been adopted to plan the community relocation in both of these municipalities, while the significant reemergence of residential and commercial developments in the coastal stretches of Kalmunai municipality have been noted. Exposure analyses have revealed that there are still some critical infrastructure situated in the tsunami hazard zones. It can be construed that these municipalities have recovered from the physical losses incurred, and spatial planning is in place for future developments considering the tsunami risk. Challenges and opportunities from their differing geographical contexts appear to have been judiciously handled. However, shortcomings are noted in actual implementation due to various reasons, such as limited resources, availability of funding and preference of communities to live close to their original lands. Improving the resilience of infrastructure by designing against the expected tsunami hazard and multi-hazards, regular verification of the early warning systems and evacuation procedures are emphasized to mitigate the impacts from future tsunami.

Vulnerability, understood as the conditions determined by physical, social, economic and environmental factors or processes that increase the potential for an individual, a community, assets or systems to be negatively affected by hazards, is a key component when assessing tsunami risk. Vulnerability can be affected by human interventions. Hence, the study of vulnerability is essential to support decision-making (e.g., land use planning and emergency planning) for more effective risk management. Vulnerability is most commonly represented through a vulnerability function that expresses the likelihood of achieving a value of a loss parameter for increasing values of a hazard intensity measure.

Tall reinforced concrete shear wall buildings used for residential purposes performed well in the 2010 Maule earthquake in Chile. Despite their good performance, in 2011 the regulations governing their design (Ministerio de Vivienda y Urbanismo 2011a, b) were changed to incorporate measures to reduce wall damage by requiring special boundary elements, along with extending the design spectrum to accommodate a broader range of soil types, among other improvements. Therefore, it is now crucial to analyse the performance of RC shear wall residential buildings designed according to the updated Chilean earthquake-resistant design standards and characterise their seismic behaviour in terms of fragility functions. However, different modelling approaches can be adopted for seismic assessment, each involving specific assumptions that significantly influence the building response. This research aims to derive the fragility of typical RC tall shear wall residential buildings in Chile located in a high seismic hazard zone, by analysing the influence of modelling assumptions on the structural response, particularly for the floor system and damping ratio, as these factors have been shown to significantly affect seismic performance. One hundred synthetic ground motion records are used to assess the seismic performance of two representative case study structures (of 9 and 17 storeys) using non-linear time history analyses. Slight, extensive, and complete damage states are selected, and fragility curves are then derived, revealing that models utilizing shell elements to represent the floor system are more efficient and better aligned with the observed behaviour of residential buildings in Chile compared to those using elastic beam elements with rigid diaphragm constraints. Moreover, it is demonstrated that damping ratios are a highly sensitive parameter, significantly influencing the collapse probability of buildings. Therefore, the use of damping ratios from studies that better reflect real-world conditions is recommended. Overall, the results show that the studied buildings do not present a risk of collapse for spectral ordinates less than or equal to 0·5 g.

There is still a gap between the structural and nonstructural components in the analysis and design stages of healthcare facilities, and as a result, earthquake-induced nonstructural damage is still causing loss of functionality despite minor structural damage. Aiming to bridge this gap, the present research focuses on the development of probabilistic damage scenarios for hospital critical rooms, taking into account the structural, nonstructural, and content interactions simultaneously. To achieve this goal, a fully equipped emergency room, intensive care unit, and operating room are simulated on the first, fourth, and fifth floors of a mid-rise hospital building and subjected to the service, design, and maximum considered earthquake levels under conventional and base-isolated support conditions. The building's floor responses are then used as input motions to assess the performance and develop fragility curves for different nonstructural elements, systems, and contents located in each critical room. Finally, probabilistic damage scenarios are developed by coupling structural, nonstructural, and content fragility curves using the performance-based earthquake engineering methodology. Results showcase the benefits of base isolation not only in reducing damage but also in ensuring high levels of functionality for all earthquake hazard levels. Conversely, functionality loss is expected in conventional hospitals during low-intensity earthquake motions due to the considerable damage to medical equipment. Moreover, it was demonstrated that solely preventing structural damage is not enough to ensure hospital functionality. Finally, it is of paramount importance to develop code-based performance objectives and expectations for nonstructural components and medical equipment under low- and design-level earthquake motions.

Currently, construction codes and standards require nonstructural fragility information to define nonstructural performance objectives and expectations for low- and design-intensity earthquake motions. To address this knowledge gap, this study focuses on the development of analytical fragility curves for unanchored medical equipment commonly found in hospital critical rooms, taking into account the building’s performance, damage progression, and content interaction simultaneously. To achieve this goal, a fully equipped emergency room, intensive care unit, and operating room are simulated on the first, fourth, and fifth floors of a mid-rise hospital building, respectively, and subjected to service, design, and maximum considered earthquake levels under fixed-to-the-base (FB) and base-isolated (BI) support conditions. The building’s floor acceleration responses are used as input motions to assess the performance of several pieces of medical equipment using rolling and sliding nonlinear models. This study has included a comprehensive uncertainty analysis to propagate different sources of uncertainty into the fragility curves. Fragility results indicate that, under FB support conditions, equipment malfunctions and failures are expected to occur during low-intensity earthquake motions, even if the hospital building experiences minor structural damage. Furthermore, knowing the damaged condition of medical equipment (malfunction/failure) is crucial for determining its availability and subsequent use to stabilize critical condition patients or save their lives. Finally, these fragility curves can be used to plan post-disaster recovery and make risk-informed decisions in healthcare facilities.

In a time of climate emergency due to global warming, nature-based coastal defence systems are attractive solutions for flood mitigation and adaptation. Coastal forests such as mangroves have received a growing interest for their disaster mitigation effectiveness such as water flow energy dissipation, hence helping communities to become more resilient (Iimura & Tanaka, 2012). The role of coastal forests as a defence measure was highlighted in the aftermath of the 2004 Indian Ocean Tsunami, which claimed the lives of more than 200,000 people and displaced millions more across fourteen countries. Post-disaster damage observations indicated that forests, particularly mangroves, reduced the impact of the tsunami wave in some locations. As a result, significant international relief and reconstruction efforts focused on extensive forest replantation of coastlines (Satake, 2014).

The role of coastal vegetation in reducing the severity of tsunami waves has been studied since. Several studies using physical modelling and computational approaches have provided insights into the wave attenuation provided by coastal vegetation, in terms of relationships between incident hydrodynamic conditions, forest configurations and wave height decay. However, there are still many gaps in knowledge, particularly in quantifying the efficacy of coastal forests in reducing inland hydrodynamic conditions (Tomiczek et al., 2020). It is therefore essential to improve the understanding on how wave heights, velocities and runup are influenced by the characteristics of the “obstacles”, e.g. the forest density, as well as the incident hydrodynamic conditions, e.g. the wave period. This study aims to address these questions conducting physical experiments using the novel pneumatic Tsunami Simulator (TS) developed by HR Wallingford together with UCL (Rossetto et al., 2011).