Framework for a City’s Performance Assessment in the Case of an Earthquake

Abstract

A comprehensive assessment of a city’s vulnerability and resilience is a prerequisite for an effective response to a natural disaster, such as an earthquake. However, an appropriate method for assessing the seismic performance of a complex urban system is still being researched. To address this gap, the purpose of this paper is to introduce a method for seismic performance assessment of a city as a socio-physical system. Therefore, various studies of individual urban components and their interactions were combined into a holistic framework and presented in a case study of a small mid-European town. The seismic vulnerability of the building inventory was assumed or assessed based on the fragility curves adopted from the literature on similar European building stock. Seismic scenarios of different earthquake intensity (PGA of 0.15 g and 0.30 g) combined with conservative and risky approaches were applied. Considering the human perspective, urban performance was evaluated on the basis of accessibility to urban services that satisfy basic human needs (for survival and protection) via graph theory measures of global efficiency and the shortest path. The temporal aspect (before the earthquake, immediately after it, after evacuation, and after recovery) was also included to obtain a comprehensive resilience assessment. It turned out that a stronger earthquake (PGA of 0.30 g) would have far-reaching consequences for the urban performance of the investigated town, and the old city center would be particularly affected. Following the event, the system’s performance is less than half as effective compared to the initial level, indicating a sharp deterioration in the quality of life as reflected in the possibility of meeting basic human needs.

A building imagery database for the calibration of machine learning algorithms

“…This system has been used in dozens of studies to develop exposure models (e.g. Crowley et al, 2020; Yepes et al, 2023), classify specific building classes (Koren and Rus, 2023; Opabola et al, 2022), and define structural classes for the scoring and development of fragility/vulnerability functions (Gentile et al, 2022; Martins and Silva, 2020; Zucconi et al, 2022). Furthermore, the employment of a well-established building taxonomy enables merging imagery from other databases following the same classification system.…”

Placing engineering in the earthquake response and the survival chain

“…In addition, rapid urbanization in the Global South has led to the construction of millions of housing units that are seismically vulnerable even though most cities already have modern seismic standards, e.g., in the Caribbean, South America, and Asia 7 . Thus, multiple communities worldwide could face unprecedented emergency responses in future large earthquakes, especially in large cities with high seismic risks 8 .…”