Comparison of modelled seismic loss against historical damage information

2020 ◽  
Author(s):  
Danhua Xin ◽  
James Daniell ◽  
Friedemann Wenzel
Keyword(s):  
Seismic Hazard ◽  
Loss Function ◽  
Seismic Risk ◽  
Risk Model ◽  
Human Life ◽  
Target Area ◽  
Seismic Risk Analysis ◽  
Damage Functions ◽  
Seismic Loss ◽  
Loss Modelling

<p>The increasing loss of human life and property due to earthquakes in past years have increased the demand for seismic risk analysis for people to be better prepared for a potential threat. With the centralization and increase of population near urban centres and megacities, earthquakes occur in these places will cause much more damage than in the past. Therefore, the quantification of seismic risk is extremely important. Seismic risk modelling results provide the spatial distribution of expected damage and loss to exposed elements in an earthquake of different magnitudes. Therefore, seismic risk model can play a key role in the following aspects: (i) to assess the potential seismic hazard and loss for a target area from both deterministic and probabilistic view; (ii) to support the long-term plan for seismic risk mitigation and preparedness; (iii) to prioritize decision making in emergency response and disaster management; and (iv) to optimize retrofitting strategies.</p><p> </p><p>The modelling of seismic risk is typically composed of three modules, namely hazard, exposure and vulnerability. Different researchers have applied different assumptions in modelled the seismic hazard, exposed stock value and their vulnerability. Therefore, uncertainty exists in every step of the loss modelling chain. Thus, it is quite essential to evaluate the reasonability of the loss modelling results. One way to check the reasonability of modelled seismic loss is by comparison with real losses derived from post-earthquake surveys. China has a long history of recording historical devastating natural disasters including major losses during earthquakes and associated secondary events, which can be dating back to 1831 B.C. (Gu, 1989). Based on this bunch of damage information, Daniell (2014) developed an empirical loss function for mainland China during his PhD study. The advantage of this loss function compared with others is its normalization of historical loss with the socio-economic indicator (e.g. Human Development Index) and its calibration of damage functions of previous events to relate to the present conditions. Therefore, the loss estimated based on the empirical loss function developed in Daniell (2014) (tagged as “empirical loss”) will be used to evaluate losses estimated purely from modelled parameters (tagged as “analytical loss”).</p><p> </p><p>Our results indicate that for both deterministic and probabilistic hazard scenarios, the empirical loss and analytical loss are within two times’ difference (i.e. the empirical loss is generally larger than analytical loss, but it is lower than two times of the analytical loss). When the building vulnerability change is scaled in the empirical loss function of Daniell (2014) by using HDI and the soil amplification effect is integrated into the analytical loss modelling process, the difference between “empirical loss” and “analytical loss” will further decrease. This congruence verifies the reliability of the parameters we use in modelling seismic loss.</p>

scholarly journals Comparison between seismic and domestic risk in moderate seismic hazard prone region: the Grenoble City (France) test site

2012 ◽  
Vol 12 (2) ◽  
pp. 511-526 ◽  
Author(s):  
F. Dunand ◽  
P. Gueguen
Keyword(s):  
Seismic Hazard ◽  
Seismic Risk ◽  
Probabilistic Approach ◽  
Test Site ◽  
Local Policy ◽  
Seismic Risk Analysis ◽  
Public Authorities ◽  
Policy Makers ◽  
Risk Acceptability ◽  
Social Importance

Abstract. France has a moderate level of seismic activity, characterized by diffuse seismicity, sometimes experiencing earthquakes of a magnitude of more than 5 in the most active zones. In this seismicity context, Grenoble is a city of major economic and social importance. However, earthquakes being rare, public authorities and the decision makers are only vaguely committed to reducing seismic risk: return periods are long and local policy makers do not have much information available. Over the past 25 yr, a large number of studies have been conducted to improve our knowledge of seismic hazard in this region. One of the decision-making concerns of Grenoble's public authorities, as managers of a large number of public buildings, is to know not only the seismic-prone regions, the variability of seismic hazard due to site effects and the city's overall vulnerability, but also the level of seismic risk and exposure for the entire city, also compared to other natural or/and domestic hazards. Our seismic risk analysis uses a probabilistic approach for regional and local hazards and the vulnerability assessment of buildings. Its applicability to Grenoble offers the advantage of being based on knowledge acquired by previous projects conducted over the years. This paper aims to compare the level of seismic risk with that of other risks and to introduce the notion of risk acceptability in order to offer guidance in the management of seismic risk. This notion of acceptability, which is now part of seismic risk consideration for existing buildings in Switzerland, is relevant in moderately seismic-prone countries like France.

Probabilistic seismic risk assessment of India

2020 ◽  
Vol 36 (1_suppl) ◽  
pp. 345-371
Author(s):  
Anirudh Rao ◽  
Debashish Dutta ◽  
Pratim Kalita ◽  
Nick Ackerley ◽  
Vitor Silva ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Risk ◽  
Risk Model ◽  
Building Design ◽  
Design Guidelines ◽  
Exposure Model ◽  
Economic Losses ◽  
Exceedance Probability ◽  
Earthquake Risk ◽  
Earthquake Insurance

This study presents a comprehensive open probabilistic seismic risk model for India. The proposed model comprises a nationwide residential and non-residential building exposure model, a selection of analytical seismic vulnerability functions tailored for Indian building classes, and the open implementation of an existing probabilistic seismic hazard model for India. The vulnerability of the building exposure is combined with the seismic hazard using the stochastic (Monte Carlo) event-based calculator of the OpenQuake engine to estimate probabilistic seismic risk metrics such as average annual economic losses and the exceedance probability curves at the national, state, district, and subdistrict levels. The risk model and the underlying datasets, along with the risk metrics calculated at different scales, are intended to be used as tools to quantitatively assess the earthquake risk across India and also compare with other countries to develop risk-informed building design guidelines, for more careful land-use planning, to optimize earthquake insurance pricing, and to enhance general earthquake risk awareness and preparedness.

Resource Allocation Model Toward Seismic Water Pipeline Risk Mitigation Measures

2019 ◽  
Author(s):  
Elnaz Peyghaleh ◽  
Tarek Alkhrdaji
Keyword(s):  
Resource Allocation ◽  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Distribution Systems ◽  
Risk Mitigation ◽  
Mitigation Measures ◽  
Seismic Risk Analysis ◽  
Allocation Model ◽  
Proposed Model

Abstract History of earthquake’s damages have illustrated the high vulnerability and risks associated with failure of water transfer and distribution systems. Adequate mitigation plans to reduce such seismic risks are required for sustainable development. The first step in developing a mitigation plan is prioritizing the limited available budget to address the most critical mitigation measures. This paper presents an optimization model that can be utilized for financial resource allocation towards earthquake risk mitigation measures for water pipelines. It presents a framework that can be used by decision-makers (authorities, stockholders, owners and contractors) to structure budget allocation strategy for seismic risk mitigation measures such as repair, retrofit, and/or replacement of steel and concrete pipelines. A stochastic model is presented to establish optimal mitigation measures based on minimizing repair and retrofit costs, post-earthquake replacement costs, and especially earthquake-induced large losses. To consider the earthquake induced loss on pipelines, the indirect loss due to water shortage and business interruption in the industries which needs water is also considered. The model is applied to a pilot area to demonstrate the practical application aspects of the proposed model. Pipeline exposure database, built environment occupancy type, pipeline vulnerability functions, and regional seismic hazard characteristics are used to calculate a probabilistic seismic risk for the pilot area. The Global Earthquake Model’s (GEM) OpenQuake software is used to run various seismic risk analysis. Event-based seismic hazard and risk analyses are used to develop the hazard curves and maps in terms of peak ground velocity (PGV) for the study area. The results of this study show the variation of seismic losses and mitigation costs for pipelines located within the study area based on their location and the types of repair. Performing seismic risk analysis analyses using the proposed model provides a valuable tool for determining the risk associated with a network of pipelines in a region, and the costs of repair based on acceptable risk level. It can be used for decision making and to establish type and budgets for most critical repairs for a specific region.

scholarly journals Spatial Seismic Hazard Variation and Adaptive Sampling of Portfolio Location Uncertainty in Probabilistic Seismic Risk Analysis

2019 ◽  
Author(s):  
Christoph Scheingraber ◽  
Martin Käser
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Adaptive Sampling ◽  
Variance Reduction ◽  
Loss Rate ◽  
Insurance Industry ◽  
Rate Variation ◽  
Seismic Risk Analysis ◽  
Location Uncertainty

Abstract. Probabilistic Seismic Risk Analysis is widely used in the insurance industry to model the likelihood and severity of losses to insured portfolios by earthquake events. Due to geocoding issues of address information, risk items are often only known to be located within an administrative geographical zone, but precise coordinates remain unknown to the modeler. In the first part of this paper, we analyze spatial seismic hazard and loss rate variation inside administrative geographical zones in western Indonesia. We find that the variation of hazard can vary strongly not only between different zones, but also between different return periods for a fixed zone. However, the spatial variation of loss rate displays a similar pattern as the variation of hazard, without depending on the return period. We build upon these results in the second part of this paper. In a recent work, we introduced a framework for stochastic treatment of portfolio location uncertainty. This results in the necessity to simulate ground motion on a high number of sampled geographical coordinates, which typically dominates the computational effort in Probabilistic Seismic Risk Analysis. We therefore propose a novel sampling scheme to improve the efficiency of stochastic portfolio location uncertainty treatment. Depending on risk item properties and measures of spatial loss rate variation, the scheme dynamically adapts the location sample size individually for insured risk items. We analyze the convergence and variance reduction of the scheme empirically. The results show that the scheme can improve the efficiency of the estimation of loss frequency curves.

Time-dependent seismic hazard and risk due to wastewater injection in Oklahoma

2021 ◽  
pp. 875529302098802
Author(s):  
Iason Grigoratos ◽  
Paolo Bazzurro ◽  
Ellen Rathje ◽  
Alexandros Savvaidis
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Risk ◽  
Risk Model ◽  
Time Dependent ◽  
Economic Losses ◽  
Motion Model ◽  
Seismicity Rate ◽  
Ground Motion Model ◽  
Seismicity Rates

In the past decade, Oklahoma has experienced unprecedented seismicity rates, following an increase in the volumes of wastewater that are being disposed underground. In this article, we perform a probabilistic assessment of the time-dependent seismic hazard in Oklahoma and incorporate these results into an integrated seismic risk model to assess the evolution of the statewide economic losses, including a conservative forecast through 2030. Our risk model employs an injection-driven earthquake rate model, a region-specific ground motion model, a recent Vs30 map, HAZUS exposure data and updated vulnerability curves for both structural and nonstructural elements, and contents. The calculations are performed using a stochastic Monte Carlo–based approach implemented in the OpenQuake engine. The resulting seismic hazard maps illustrate the incompatibility of the regional seismic provisions with the current seismicity. In 2015, in particular, the induced seismic hazard in several places in Oklahoma was higher than along the San Andreas fault. During the peak of seismicity in 2015, the seismic risk was 275 times higher than the background level, with the vast majority of losses originating from damages to nonstructural elements and contents. Our direct economic loss estimates are in reasonable agreement with the paid insurance claims, but show significant sensitivity to the ground motion model selection. The proposed risk model, with possible regular updates on the seismicity rate forecast, can help stakeholders define acceptable production levels.

Seismic Risk Analysis of Regular Girder Bridge Subjected to Mainshock-Aftershock Sequences

2021 ◽  
Author(s):  
LIBO CHEN ◽  
Jianhong Zhou ◽  
Qiluan Zhou
Keyword(s):  
Risk Analysis ◽  
Seismic Hazard ◽  
Seismic Risk ◽  
Structural Damage ◽  
Damage Model ◽  
Earthquake Sequence ◽  
High Rate ◽  
Seismic Risk Analysis ◽  
Aftershock Sequences ◽  
Seismic Disaster

Abstract When a structure is subjected to an earthquake sequence, the high rate of aftershocks after the mainshock and cumulative damage caused by the earthquake sequence make the structure very dangerous. Considering the uncertainty in seismic occurrences, structural damage is often predicted using a seismic risk analysis. This approach has become a main measure for seismic disaster assessment, and provides a reasonable reference for post-earthquake emergency response decision-making and pre-earthquake seismic design. Therefore, it is of great significance to study a seismic risk analysis considering the effect(s) of aftershocks. In this study, the aftershock hazard is estimated for a post-mainshock environment based on an aftershock probabilistic seismic hazard analysis. Considering the uncertainty regarding the mainshock and aftershock occurrences, in addition to the functional relationship between the mainshock and aftershock parameters, the aftershock seismic hazard is estimated for the pre-mainshock environment. The mainshock fragility and aftershock fragility of regular girder bridges are evaluated based on the Kunnath damage model. Finally, considering the damage accumulation in bridge structures, the seismic hazard and seismic fragility are combined to establish a post-mainshock aftershock seismic risk framework and pre-mainshock mainshock-aftershock seismic risk analysis framework. Based on these, the mainshock risk and mainshock-aftershock risk are compared to verify the importance of considering the aftershock effects in seismic disaster assessments. The aftershock risks for the bridges of different post-mainshock damage states are compared, and the influence of the initial damage after the mainshock on the damage to the structure in the post-mainshock environment is studied.

scholarly journals Seismic hazard assessment of Greenland

2007 ◽  
Vol 13 ◽  
pp. 57-60 ◽  
Author(s):  
Peter Voss ◽  
Stine Kildegaard Poulsen ◽  
Sebastian Bjerregaard Simonsen ◽  
Søren Gregersen
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Seismic Risk ◽  
Human Life ◽  
Seismic Hazard Assessment ◽  
Earthquake Activity ◽  
Economic Costs ◽  
Richter Scale ◽  
Hazard And Risk

Earthquake activity in Greenland has been registered and mapped since 1907 (Larsen et al. 2006) and thus a long (albeit relatively sparse) record of seismic activity is available for evaluation of seismic hazard and risk. Seismic hazard assessment is carried out by judging the probability of future earthquakes in a given region and is based on statistic treatment of earthquake data. The determination of the seismic hazard is the first step in an evaluation of seismic risk, i.e. the possible economic costs and loss of human life after an earthquake. The motivation for this seismic hazard study is the registration of four significant earthquakes in Greenland in 2005. The Geological Survey of Denmark and Greenland (GEUS) received reports of all four earthquakes from residents who had felt the shaking. The 2005 earthquakes were located at or near Qeqertarsuaq on 30 March, Sisimiut on 23 July, Station Nord on 30 August and Attu on 23 October (Fig. 1), with magnitudes on the Richter scale of 4.3, 4.1, 5.1 and 2.5, respectively. The earthquake in Attu led to the inhabitants fleeing in their boats.

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