On the treatment of uncertainty in seismic vulnerability and portfolio risk assessment

The semi-nonparametric (SNP) modeling of the return distribution has been proved to be a flexible and accurate methodology for portfolio risk management that allows two-step estimation of the dynamic conditional correlation (DCC) matrix. For this SNP-DCC model, we propose a stepwise procedure to compute pairwise conditional correlations under bivariate marginal SNP distributions, overcoming the curse of dimensionality. The procedure is compared to the assumption of Dynamic Equicorrelation (DECO), which is a parsimonious model when correlations among the assets are not significantly different but requires joint estimation of the multivariate SNP model. The risk assessment of both methodologies is tested for a portfolio on cryptocurrencies by implementing backtesting techniques and for different risk measures: Value-at-Risk, Expected Shortfall and Median Shortfall. The results support our proposal showing that the SNP-DCC model has better performance for a smaller confidence level than the SNP-DECO model, although both models perform similarly for higher confidence levels.

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Seismic risk assessment of RC curved bridges through fragility curves

IABSE Symposium, Guimarães 2019: Towards a Resilient Built Environment Risk and Asset Management ◽

10.2749/guimaraes.2019.1488 ◽

2019 ◽

Author(s):

Nina N. Serdar ◽

Jelena R. Pejovic ◽

Radenko Pejovic ◽

Miloš Knežević

Keyword(s):

Risk Assessment ◽

Urban Areas ◽

Seismic Risk ◽

Seismic Vulnerability ◽

Fragility Curves ◽

Curved Bridges ◽

Damage State ◽

Seismic Risk Assessment ◽

Probability Of Exceedance ◽

Damage States

<p>It is of great importance that traffic network is still functioning in post- earthquake period, so that interventions in emergency situations are not delayed. Bridges are part of the traffic system that can be considered as critical for adequate post-earthquake response. Their seismic response often dominate the response and reliability of overall transportation system, so special attention should be given to risk assessment for these structures. In seismic vulnerability and risk assessment bridges are often classified as regular or irregular structures, dependant on their configuration. Curved bridges are considered as irregular and unexpected behaviour during seismic excitation is noticed in past earthquake events. Still there are an increasing number of these structures especially in densely populated urban areas since curved configuration is often suitable to accommodate complicated location conditions. In this paper special attention is given to seismic risk assessment of curved reinforce concrete bridges through fragility curves. Procedure for developing fragility curves is described as well as influence of radius curvature on their seismic vulnerability is investigated. Since vulnerability curves provide probability of exceedance of certain damage state, four damage states are considered: near collapse, significant damage, intermediate damage state, onset of damage and damage limitation. As much as possible these damage states are related to current European provisions. Radius of horizontal curvature is varied by changing subtended angle: 25 °, 45 ° and 90 °. Also one corresponding straight bridge is analysed. Nonlinear static procedure is used for developing of fragility curves. It was shown that probability of exceedance of certain damage states is increased as subtended angle is increased. Also it is determined that fragility of curved bridges can be related to fragility of straight counterparts what facilitates seismic evaluation of seismic vulnerability of curved bridges structures.</p>

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A Contribution to a UHS-Based Seismic Risk Assessment in Croatia—A Case Study for the City of Osijek

Sustainability ◽

10.3390/su12051796 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1796 ◽

Cited By ~ 2

Author(s):

Gordana Pavić ◽

Marijana Hadzima-Nyarko ◽

Borko Bulajić

Keyword(s):

Risk Assessment ◽

Seismic Risk ◽

Seismic Vulnerability ◽

Modern Society ◽

Seismic Risk Assessment ◽

Hazard Exposure ◽

Initial Stage ◽

Vulnerability Of Buildings ◽

The Many ◽

The Impact

Due to increases in the number of inhabitants and their concentrations in densely populated areas, there is a growing need in modern society to be cautious towards the impact of catastrophic natural events. An earthquake is a particularly major example of this. Knowledge of the seismic vulnerability of buildings in Europe and around the world has deepened and expanded over the last 20 years, as a result of the many devastating earthquakes. In this study, a review of seismic risk assessment methods in Croatia was presented with respect to the hazard, exposure, and vulnerability of buildings in the fourth largest city (Osijek) in Croatia. The proposed algorithm for a detailed risk assessment was applied to a database and is currently in its initial stage.

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Application of the Beck model to stock markets: Value-at-Risk and portfolio risk assessment

Physica A Statistical Mechanics and its Applications ◽

10.1016/j.physa.2007.10.023 ◽

2008 ◽

Vol 387 (5-6) ◽

pp. 1225-1246 ◽

Cited By ~ 13

Author(s):

M. Kozaki ◽

A.-H. Sato

Keyword(s):

Risk Assessment ◽

At Risk ◽

Stock Markets ◽

Value At Risk ◽

Portfolio Risk

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Study Concerning the Level of Seismic Risk in Iasi Municipality

Advanced Engineering Forum ◽

10.4028/www.scientific.net/aef.21.86 ◽

2017 ◽

Vol 21 ◽

pp. 86-93

Author(s):

Georgiana Bunea ◽

Cornel Doniga ◽

Gabriela Maria Atanasiu

Keyword(s):

Risk Assessment ◽

Population Density ◽

Extreme Events ◽

Seismic Risk ◽

Seismic Vulnerability ◽

Seismic Risk Assessment ◽

The Impact ◽

The Town ◽

General Perspective

Throughout its history, Iasi municipality has been subjected to many important seismic actions caused by earthquakes produced in Vrancea area, Romania. The impact of these extreme events upon the town increased in time as it developed, more buildings were constructed and the population density rose. The classes of buildings identified in Iasi municipality have been designed on different seismic standards, some of them being erected without taking into account the effect of seismic actions. The differences between the seismic norms’ regulations and the important earthquake’s history some of the buildings have, are outlining the need of seismic risk assessment in Iasi municipality. This paper aims to present some of the results of the seismic risk study in Iasi municipality, which was based on the completed seismic risk surveys and on the regulations of seismic standards. In this study, only the dwelling structures built before 1990 were considered, and the results were distributed on neighborhoods, for obtaining a general perspective on the seismic risk state of each area, by considering the buildings’ seismic vulnerability.

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