ELER software – a new tool for urban earthquake loss assessment

ABSTRACT: The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled “Network of Research Infra-structures for European Seismology, NERIES”. This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships.

Portugal has its past marked by the occurrence of very destructive earthquakes. In the wellknown 1755 Lisbon earthquake, despite the various estimates proposed by the scientific community it is fair to assume that in Lisbon, more than 50% of the buildings were heavily damaged or destroyed and about 10% of the population perished. In the beginning of the last century, a moderate event of magnitude 6.6 Mw struck the village of Benavente, causing 46 fatalities and damaging more than 3000 dwellings. Besides this moderate seismicity, the Portuguese building stock in highly populated centres is characterized by a large fraction of masonry buildings, which typically have a higher seismic vulnerability. For these reasons, it is clear that a reliable and accurate platform for damage estimation based on deterministic earthquake scenarios is fundamental. This study provides an overview of the initial development of a damage estimation framework for Portugal, as well as a description of the components and input models required for the various calculations. This system has been established at the Faculty of Engineering of the University of Porto, and it will allow not only earthquake engineers and risk modelers to access damage information and launch scenario calculations, but also other experts and decision makers whose needs might have a particular purpose, such as emergency planning.

International Journal of Safety and Security Engineering, 2017

Earthquake loss estimation (ELE), generally also referred to as earthquake risk assessment, is a comparably young research discipline which, at first, relied on empirical observations based on a macroseismic intensity scale. Later, with the advent of methodologies and procedures that are based on theoretical simulation in estimating physical damage under earthquake loading, the analytical approach for ELE was formulated. The open-source software SELENA, which is a joint development of NORSAR (Norway) and the University of Alicante (Spain), is undergoing a constant development. One of the more recent features being included is the possibility to address topographic amplification of seismic ground motion. Additionally, SELENA has been adapted by including various methods for the analytical computation of structural damage and loss. SELENA now offers complete flexibility in the use of different types of fragility curves based on various ground motion intensity parameters (e.g. PGA, Sa, Sd), which has been suggested by many recently released guidelines (e.g. FEMA P-58, GEM-ASV, SYNER-G, HAZUS-MH). Besides, under the framework of the ongoing Horizon 2020 LIQUEFACT project, SELENA is extended in order to allow the consideration of liquefaction-induced ground displacements and respective structural damage. In general, software tools for ELE are particularly useful in two different settings, i.e., for disaster management and (re)insurance purposes. Both sectors pose very different demands on ELE studies: while the (re)insurance sector is foremost interested in the direct and indirect economic losses caused by an earthquake to its insured physical assets, those institutions (often governmental and nongovernmental organizations) in charge of disaster emergency management and response are more interested in reliable estimates on human losses and the potential short-and long-term social consequences. Being aware about these peculiar differences between software tools for disaster management and insurance applications, NORSAR/UA thereby offers two in its core similar software tools, i.e., the opensource software SELENA and the proprietary software PML (Probable Maximum Loss) which is actively used by the insurance association in Chile (South America) since 2011.

I. ABSTRACT Seismic damage simulation and loss estimation is a very important task for the civil protection departments and urban planning policies for earthquake hazard mitigation. Many different software packages have been produced around the world in order to provide accurate loss estimates. Building damage functions for ground shaking include: (1) fragility curves that describe the probability of reaching or exceeding different states of damage given peak building response, and (2) building capacity (pushover) curves that are used (with damping-modified demand spectra) to determine peak building response. For use in lifeline damage evaluation, a separate set of building fragility curves expresses the probability of structural damage in terms of peak ground acceleration (PGA). Damage is described by one of four

Journal of Seismology, 2012

On March 4, 1977, an earthquake with a moment magnitude M w 7.4 at a hypocentral depth of 94 km hit the Vrancea region (Romania). In Bucharest alone, the earthquake caused severe damage to 33,000 buildings while 1,424 people were killed. Under the umbrella of the SAFER project, the city of Bucharest, being one of the larger European cities at risk, was chosen as a test bed for the estimation of damage and connected losses in case of a future large magnitude earthquake in the Vrancea area. For the conduct of these purely deterministic damage and loss computations, the open-source software SELENA is applied. In order to represent a large event in the Vrancea region, a set of deterministic scenarios were defined by combining ranges of focal parameters, i.e., magnitude, focal depth, and epicentral location. Ground motion values are computed by consideration of different ground motion prediction equations that are believed to represent earthquake attenuation effects in the region. Variations in damage and loss estimates are investigated through considering different sets of building vulnerability curves (provided by HAZUS-MH and various European authors) to characterize the damaging behavior of prevalent building typologies in the city of Bucharest.

Journal of Earthquake Engineering, 2019

Relatively simple method for seismic loss assessment is presented based on probabilistic hazard, event scenarios and local building inventory. EMS98-dependent vulnerability model is transformed to continuous fragility functions correlating damage probability to peak ground acceleration. The proposed method illustrated over 59,950 inventoried buildings

Abstract: This chapter summarizes the work done over last decades regarding the development of new approaches and setting up of new applications for earthquake rapid response systems that function to estimate earthquake losses in quasi real time after an earthquake. After a critical discussion of relevant earthquake loss estimation methodologies, the essential features and the characteristics of the available loss estimation software are summarized. Currently operating near real time loss estimation tools can be classified under two main categories depending on the size of area they cover: Global and Local Systems. For the global or regional near real time loss estimation systems: GDACS, WAPMERR, PAGER and NERIES-ELER methodologies are presented. Examples are provided for the local rapid earthquake loss estimation systems including: Taiwan Earthquake Rapid Reporting System, Realtime Earthquake Assessment Disaster System in Yokohama, Real Time Earthquake Disaster Mitigation System of the Tokyo Gas Co., and Istanbul Earthquake Rapid Response System.

2016

Algeria is one of the countries that have experienced several strong to moderate earthquakes during the last decades. The experience of these events showed that the elaboration of adequate intervention measures was done after the first in situ inspections, which may take long time to provide information and therefore decreases the chance to find survivors. This delay is due to the lack of different means to locate quickly, at the early hours, the affected areas and due also to the uncertain alarm level to be given. In order to enhance the rapid response and emergency operation, disaster mitigation measures can be done. The present work consists on a development of an integrated rapid earthquake loss assessment model. The main motivation through this development is the ability to estimate the probable seismic damage and their spatial distribution in an affected area by a potential earthquake, according to the existing building context in Algeria. This framework based on the Algerian ...

Natural Hazards, 2005

Prognostic estimations of the expected number of killed or injured people and about the approximate cost associated with the damages caused by earthquakes are made following a suitable methodology of wide-ranging application. For the preliminary assessment of human life losses due to the occurrence of a relatively strong earthquake we use a quantitative model consisting of a correlation between the number of casualties and the earthquake magnitude as a function of population density. The macroseismic intensity field is determined in accordance with an updated anelastic attenuation law, and the number of casualties within areas of different intensity is computed using an application developed in a geographic information system (GIS) environment, taking advantage of the possibilities of such a system for the treatment of space-distributed data. The casualty rate, defined as the number of killed people divided by the number of inhabitants of the affected region, is also computed and we show its variation for some urban concentrations with different population density. For a rough preliminary evaluation of the direct economic cost derived from the damages, equally through a GIS-based tool, we take into account the local social wealth as a function of the gross domestic product of the country. This last step is performed on the basis of the relationship of the macroseismic intensity to the earthquake economic loss in percentage of the wealth. Such an approach to the human casualty and damage levels is carried out for sites near important cities located in a seismically active zone of Spain, thus contributing to an easier taking of decisions in emergency preparedness planning, contemporary earthquake engineering and seismic risk prevention.

Soil Dynamics and Earthquake Engineering, 2009

The rapid urban development in Istanbul has lead to an increase in the exposure levels of the urban vulnerability. Due to the steadily increasing population, with improper land-use planning, inappropriate construction techniques and inadequate infrastructure systems, associated with an existing high hazard level, Istanbul is one of the most risky cities in the Mediterranean region. Estimations of casualties and losses, expected for given earthquake scenarios, are necessary to develop sustainable rehabilitation programs and for improving preparedness. Deterministic hazard scenarios and time-dependent probabilistic hazard assessment were used as input to a GIS-based loss estimation model, to evaluate the earthquake risk for Istanbul. The deterministic ground shaking scenarios, used for loss estimation in Istanbul, were defined in terms of acceleration and velocity time series for recognized reference earthquakes caused by different rupture models along extended sources. The ground motions were calculated for the whole metropolitan area extending over a grid system of 25 Â 100 km 2 .

Springer Natural Hazards, 2018

This study proposes the methodology for an innovative Earthquake Risk Assessment (ERA) framework to calculate seismic hazard maps in regions where limited seismo-tectonic information exists. The tool calculates the seismic hazard using a probabilistic seismic hazard analysis (PSHA) based on a Monte-Carlo approach, which generates synthetic earthquake catalogues by randomizing key hazard parameters in a controlled manner. All the available data was transferred to GIS format and the results are evaluated to obtain a hazard maps that consider site amplification, liquefaction susceptibility and landslide hazard. The effectiveness of the PSHA methodology is demonstrated by carrying out the hazard analysis of Marmara region (Turkey), for which benchmark maps already exist. The results show that the hazard maps for Marmara region compare well with previous PSHA studies and with the National Building Code map. The proposed method is particularly suitable for generating hazard maps in developing countries, where data is not available or easily accessible.

2014

Algeria is one of the countries where the seismic activity is high; it has experienced several moderate to strong earthquakes, during the last three decades, causing considerable damage in the urban areas. This seismic risk threats more particularly the big cities, which contain very important urban nuclei. Constantine city, located in the north-eastern part of Algeria, has an important administrative, economic, scientific and cultural position and knew a significant urban evolution during the different periods of its history. This city is located in an active seismicity region and has been stricken in the past by several important earthquakes where the most recent took place on October 27th, 1985 with a magnitude Ms = 5.9. Constantine presents a very high seismic risk, because of its dense housing and high concentration of population (2374 hab/km2), which requires an assessment in order to take preventive measures to reduce losses in case of major event. In this context, an earthqu...

Journal of Seismology and Earthquake Engineering, 2011

Metropolitan Tehran, as the capital, the economic and political center, and the most populated city in Iran, has a special position in earthquake preparation, mitigation and response. Tehran is vulnerable to earthquakes and is expecting a destructive earthquake with a magnitude greater than 7. In the present paper, the items of hazard analysis, vulnerability assessment, and loss estimation in respect of Tehran are introduced, and the relevant research concerning the category of physical and structural damage is investigated. The results from vulnerability assessment indicate the vulnerability of a major part of the buildings in Tehran. The results from the loss estimation indicate a high percentage of damage in the event of an earthquake in Tehran. Furthermore, based on the loss estimation results, the likely amount of debris generated and possibilities for positioning of the temporary housing are provided. The results emphasize the necessity of short-term, average-term and long-ter...

Natural hazards, especially earthquakes, cause disasters when they hit large settlements such as metropolitan areas. After the first shock, the damage is counted by deaths and injuries. In a while, the destroying effects of disaster appear on economic asset of the region. Direct losses including damages in buildings and lifelines can caused non-structural or indirect losses as interruption of business activities and services. Loss estimation techniques have been developed to evaluate losses from earthquakes and other natural hazards. Recently, loss estimation models have improved due to advances in information technology and have been automated using Geographic Information Systems.

2017

Italian territory is particularly sensitive to seismic actions. The Amatrice earthquake on August 24th 2016 confirmed this aspect. Such an event, nothing but extraordinary, has been able to cause huge and tragic damages. The direct knowledge of building features is the only prior measure to face seismic events. In order to get a realistic scenario of the urban damage distribution, the determination of useful seismic vulnerability assessment tools at urban scale becomes a priority. The widespread application of seismic vulnerability assessment sheets and the related data transformation into urban damage distribution plans is exactly what municipalities need. Main advantages are both in the chance of prior knowing the most affected areas to focus on for retrofitting interventions and in the possibility of organizing optimal emergency plans. In European framework, in the last decade, the Risk-UE project has played an important role. The Risk-UE project has proposed two methods for vuln...