Scenario-based earthquake hazard and risk assessment for Baku (Azerbaijan)

A. Ismail-Zadeh,G. Babayev,J.-L. Le Mouël

doi:10.5194/nhess-10-2697-2010

Abstract

Abstract. A rapid growth of population, intensive civil and industrial building, land and water instabilities (e.g. landslides, significant underground water level fluctuations), and the lack of public awareness regarding seismic hazard contribute to the increase of vulnerability of Baku (the capital city of the Republic of Azerbaijan) to earthquakes. In this study, we assess an earthquake risk in the city determined as a convolution of seismic hazard (in terms of the surface peak ground acceleration, PGA), vulnerability (due to building construction fragility, population features, the gross domestic product per capita, and landslide's occurrence), and exposure of infrastructure and critical facilities. The earthquake risk assessment provides useful information to identify the factors influencing the risk. A deterministic seismic hazard for Baku is analysed for four earthquake scenarios: near, far, local, and extreme events. The seismic hazard models demonstrate the level of ground shaking in the city: PGA high values are predicted in the southern coastal and north-eastern parts of the city and in some parts of the downtown. The PGA attains its maximal values for the local and extreme earthquake scenarios. We show that the quality of buildings and the probability of their damage, the distribution of urban population, exposure, and the pattern of peak ground acceleration contribute to the seismic risk, meanwhile the vulnerability factors play a more prominent role for all earthquake scenarios. Our results can allow elaborating strategic countermeasure plans for the earthquake risk mitigation in the Baku city.

Highlights

Earthquake risk is a measure that combines, over a given time, the likelihood and the consequences of a set of earthquake scenarios (Beer and Ismail-Zadeh, 2003)
To evaluate earthquake risk for the Baku city for four earthquake scenarios, we convolve six discrete functions determined at each cell of the model S (28 × 20 cells): the seismic hazard function f1, which represents a surface PGA normalized with the same normalization factor for all earthquake scenarios; landslides occurrence; vulnerability in terms of the building structures damage, and the normalized population features; exposed value; and normalized Gross Domestic Product (GDP) per capita
The pattern of earthquake risk follows the pattern of seismic hazard, but does not mimic it because of other factors contributing to risk

Summary

Introduction

Earthquake risk is a measure that combines, over a given time, the likelihood and the consequences of a set of earthquake scenarios (Beer and Ismail-Zadeh, 2003). The risk can be estimated as the probability of harmful consequences or expected losses (of lives and property) and damages (e.g. people injured, economic activity disrupted, environment damaged) due to an earthquake resulting from interactions between seismic hazards (H ), vulnerability (V ), and exposed values (E). Earthquake risk (R) is expressed by the convolution of these three parameters: R = H ⊗ V ⊗ E. Each of those factors is disaggregated into the more specific parameters that comprise it. Infrastructure, critical facilities, and important communication system represent the values exposed to damage due to an earthquake and should be taken into account in risk estimation. The proper approach to the problem of earthquake risk estimation and risk management should include consideration of all the contributing components

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Conclusion