Estimating Tsunami-Induced Building Damage through Fragility Functions: Critical Review and Research Needs

Tsunami damage, fragility, and vulnerability functions are statistical models that provide an estimate of expected damage or losses due to tsunami. They allow for quantification of risk, and so are a vital component of catastrophe models used for human and financial loss estimation, and for land-use and emergency planning. This paper collates and reviews the currently available tsunami fragility functions in order to highlight the current limitations, outline significant advances in this field, make recommendations for model derivation, and propose key areas for further research. Existing functions are first presented, and then key issues are identified in the current literature for each of the model components: building damage data (the response variable of the statistical model), tsunami intensity data (the explanatory variable), and the statistical model that links the two. Finally, recommendations are made regarding areas for future research and current best practices in deriving tsunami fragility functions (see Discussion, Recommendations, and Future Research). The information presented in this paper may be used to assess the quality of current estimations (both based on the quality of the data, and the quality of the models and methods adopted) and to adopt best practice when developing new fragility functions

Earthquake reconnaissance data sources, a literature review

Earthquakes are one of the most catastrophic natural phenomena. After an earthquake, earthquake reconnaissance enables effective recovery by collecting data on building damage and other impacts. This paper aims to identify state-of-the-art data sources for building damage assessment and provide guidance for more efficient data collection. We have reviewed 39 articles that indicate the sources used by different authors to collect data related to damage and post-disaster recovery progress after earthquakes between 2014 and 2021. The current data collection methods have been grouped into seven categories: fieldwork or ground surveys, omnidirectional imagery (OD), terrestrial laser scanning (TLS), remote sensing (RS), crowdsourcing platforms, social media (SM) and closed-circuit television videos (CCTV). The selection of a particular data source or collection technique for earthquake reconnaissance includes different criteria depending on what questions are to be answered by these data. We conclude that modern reconnaissance missions cannot rely on a single data source. Different data sources should complement each other, validate collected data or systematically quantify the damage. The recent increase in the number of crowdsourcing and SM platforms used to source earthquake reconnaissance data demonstrates that this is likely to become an increasingly important data source

Training of Crisis Mappers and Map Production from Multi-sensor Data: Vernazza Case Study (Cinque Terre National Park, Italy)

This aim of paper is to presents the development of a multidisciplinary project carried out by the cooperation between Politecnico di Torino and ITHACA (Information Technology for Humanitarian Assistance, Cooperation and Action). The goal of the project was the training in geospatial data acquiring and processing for students attending Architecture and Engineering Courses, in order to start up a team of "volunteer mappers". Indeed, the project is aimed to document the environmental and built heritage subject to disaster; the purpose is to improve the capabilities of the actors involved in the activities connected in geospatial data collection, integration and sharing. The proposed area for testing the training activities is the Cinque Terre National Park, registered in the World Heritage List since 1997. The area was affected by flood on the 25th of October 2011. According to other international experiences, the group is expected to be active after emergencies in order to upgrade maps, using data acquired by typical geomatic methods and techniques such as terrestrial and aerial Lidar, close-range and aerial photogrammetry, topographic and GNSS instruments etc.; or by non conventional systems and instruments such us UAV, mobile mapping etc. The ultimate goal is to implement a WebGIS platform to share all the data collected with local authorities and the Civil Protectio

Imagining disasters in the era of climate change : is Japan’s seawall a new Maginot Line?

Following the Great East Japan earthquake, tsunami and nuclear disaster of 11 March 2011, the Japanese government began constructing a series of 440 seawalls along the north-eastern coast of Honshu. Cumulatively measuring 394.2km, they are designed to defend coastal communities against tsunami that frequently strike the region. We present a case study of the new seawall in Tarō, Iwate Prefecture, which had previously constructed massive sea defences in the wake of two tsunami in 1896 and 1933, which were subsequently destroyed in 2011. We ask whether the government has properly imagined the next disaster for the era of climate change and, therefore, whether its rationale for Tarō’s new seawall is sufficient. We argue that the government has implemented an incremental strengthening of Tarō’s existing tsunami defence infrastructure. Significantly, this does not anticipate global warming driven sea level rise, which is accelerating, and which requires transformational adaptation. This continues a national pattern of disaster preparedness and response established in the early 20th century, which resulted in the failure to imagine the 2011 tsunami. We conclude by recalling the lessons of France’s Maginot Line and invoke the philosophy of Tanaka Shōzō, father of Japan’s modern environmental movement, who urged Japanese to adjust to the flow (nagare) of nature, rather than defend against it, lest they are undone by the force of its backflow (gyakuryū)

Geology in Environmental Management

From the geological perspective, the two overriding environmental management concerns are the destructive impact of hazardous natural events on human health and property and the deleterious impact of human activity on the natural environment. The knowledge derived from the geological sciences serves as the basis for a more enlightened approach to the reduction of unnecessary risk involved in the siting and construction of buildings and transportation networks, as well as the extraction of natural resources and waste management. Armed with such knowledge along with political sensitivity, environmental managers will have opportunities for positive social impact in negotiating the challenges as they weigh costs, risks, and benefits. When considering natural resource and energy issues, environmental managers should foster science-based solutions to maximize resource utilization while minimizing harmful impacts, bearing in mind externalities and long-term consequences. The chapter provides an overview of key geological aspects of environmental management, illustrating fundamental principles via representative examples. The main geological subjects addressed include volcanic eruptions, earthquakes, coastal processes, fresh water resources, waste management, and fossil fuel resources. They are discussed in tandem with their associated environmental problems and risks

Probabilistic Tsunami Hazard and Damage Assessment of the Built Environment : Applied at Seaside, Oregon

Damage estimates to the built environment from tsunamis are important for disaster mitigation, including planning emergency response and recovery. This dissertation evaluates the damage states of buildings in a small urban coastal city, Seaside, Oregon, from tsunami hazards generated by a Cascadia Subduction Zone (CSZ) event. This study is separated into two parts: (1) tsunami hazard assessment, and (2) tsunami damage assessment of buildings. For the tsunami hazard assessment, a new method is presented to characterize the randomness of the fault slip in terms of the moment magnitude, peak slip location, and a fault slip shape distribution parameterized as a Gaussian distribution. For the tsunami inundation resulting from the seismic event, five tsunami intensity measures (IMs) are estimated: (1) the maximum inundation depth, h[subscript Max], (2) the maximum velocity, V[subscript Max], (3) the maximum momentum flux, M[subscript Max], (4) the initial arrival time exceeding a 1 m inundation depth, T[subscript A], and (5) the duration exceeding a 1 m inundation depth, T[subscript h], and presented in the form of annual exceedance probabilities conditioned on a full-rupture CSZ event. The IMs are generally observed to increase as the moment magnitude increases, as the proximity of the peak slip becomes closer to the study area, and as the distribution of fault shape narrows. Among the IMs, the arrival time (TA) shows a relatively weak sensitivity to the aleatory uncertainty while the other IMs show significant sensitivity, especially M[subscript Max]. It is observed at the shoreline that MMax increases by an order of magnitude from the 500-year to the 1,000-year event, while h[subscript Max] increases by a factor of 3, and TA decreases by only factor of 0.05. The intensity of IMs generally decreases inland, but there are also varying dependencies on bathymetry. For example, a shorter inundation duration, Th ( 3 m) while a longer Th (~100 min) is observed near the river and creek. For the tsunami damage assessment, the annual exceedance of the IMs, h[subscript Max] and M[subscript Max] are used to estimate building damage using a fragility curve analysis. Tax lot data, Google Street View, and field reconnaissance surveys are used to classify the buildings at a community scale and match with existing fragility curves according to construction material, floor level and build year. The fragility analysis is used to estimate the damage probability of buildings for a 1,000-year event conditioned on a full-rupture CSZ event. The sensitivity of building damage to the both the aleatory and epistemic uncertainty involved in the process of damage estimation are presented. Fragility curves based on depth and based on momentum flux both generally show higher damage probability for structures that are wooden and closer to the shoreline than those that are reinforced concreted (RC) and landward of the shoreline. However, a relatively high damage probability was found at the river and creek region from the fragility curve analysis using h[subscript Max]. Within 500 m from the shoreline, wood structure damage shows a significant sensitivity to the aleatory uncertainty of the tsunami generation from the CSZ event. On the other hand, RC structure damage showed equal sensitivity to the aleatory uncertainty of the tsunami generation as well as the epistemic uncertainties due to the numerical modelling of the tsunami inundation (friction), the building classification (material and build year), and the type of fragility curves (depth or momentum type curves). Further from the shoreline, the wood structures showed similar uncertainties to the aleatory and epistemic uncertainties

New Perspectives in the Definition/Evaluation of Seismic Hazard through Analysis of the Environmental Effects Induced by Earthquakes

The devastating effects caused by the recent catastrophic earthquakes that took place all over the world from Japan, New Zealand, to Chile, as well as those occurring in the Mediterranean basin, have once again shown that ground motion, although a serious source of direct damage, is not the only parameter to be considered, with most damage being the result of coseismic geological effects that are directly connected to the earthquake source or caused by ground shaking. The primary environmental effects induced by earthquakes as well as the secondary effects (sensu Environmental Seismic Intensity - ESI 2007 scale) must be considered for a more correct and complete evaluation of seismic hazards, at both regional and local scales. This Special Issue aims to collect all contributions that, using different methodologies, integrate new data produced with multi-disciplinary and innovative methods. These methodologies are essential for the identification and characterization of seismically active areas, and for the development of new hazard models, obtained using different survey techniques. The topic attracted a lot of interest, 19 peer-reviewed articles were collected; moreover, different areas of the world have been analyzed through these methodologies: Italy, USA, Spain, Australia, Ecuador, Guatemala, South Korea, Kyrgyzstan, Mongolia, Russia, China, Japan, and Nepal