Terms Of Macroseismic Intensity Research Articles

Macroseismic intensity attenuation models calibrated in Mw for Italy

This study aims at developing new macroseismic intensity attenuation models valid for Italy by exploiting the most updated macroseismic dataset and earthquakes catalogue, as well as the information obtained from a critical analysis of the most recent models in the literature. Several different attenuation models have been calibrated as a function of the moment magnitude (Mw) and epicentral distance from 16,260 intensity data points, that are related to 119 earthquakes occurred after 1900. According to trends and residuals analysis, the preferred calibrated intensity attenuation function is a Log-Linear model for epicentral distance (Repi in km) and a linear model for Mw as:IMCS=1.81-2.61LogR-0.0039R+1.42Mw\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$I\\left( {MCS} \\right) = {1}.{81} - {2}.{61}LogR - 0.00{39}R + {1}.{42}Mw$$\\end{document}with pseudo hypocentral distance R=Repi2+9.872\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$R = \\sqrt {R_{epi}^{2} + \\left( {9.87} \\right)^{2} }$$\\end{document}; the estimated standard deviation is σ = 0.75. Also noteworthy is another model for macroseismic intensity attenuation that proved to be as good as the best model and shows higher sensitivity to physical parameters, such as focal depth and magnitude, especially in the epicentral area. Performance of all calibrated models was also checked on an independent set of 15 post-1900 Italian earthquakes. One of the results of the present work is the opportunity to define earthquake scenarios (e.g. probabilistic seismic hazard maps) in terms of Macroseismic Intensity and its related standard deviation, avoiding the uncertainties due to the conversion of various ground shaking parameters into intensity values.

DDLAFS — QGIS plugin for dominant directions of the local active fault system estimation

QGIS is a widely used open-source geographic information system. DDLAFS is a specialized plugin in Python to solve thematic problems. The plugin is designed as a set of functions allowing to calculate the dominant directions of the regional active fault system ψi. The estimation of the dominant directions of the local active fault system is given within a circular area ∆R, where R is a user-defined radius. The centres of regions ∆R should be represented by a set of point objects {g}. These may be epicentres of main shocks, seismogenic nodes, regular grid points, etc. If {g(M)} is represented by data on seismic events, R(g) can be determined depending on the magnitude M of a certain earthquake. The plugin provides an estimate of R(M) using the dependence [11]. For one area, n dominant directions can be determined, each of which corresponds to an empirical value of the probability density distribution of azimuths of active faults, {ψi, pi | i = 1, ... n; ∑pi = 1}. The DDLAFS plugin is designed as part of an anisotropic seismic model in terms of macroseismic intensity [6].

Macroseismic intensity hazard maps for Italy based on a recent grid source model

Seismic hazard maps from probabilistic seismic hazard analysis or PSHA collect, at different sites, the values of the (site-specific) ground motion intensity measures of interest that, taken individually, have the same exceedance return period. For large-scale analyses, a widely used intensity measure is the macroseismic (MS) intensity, that provides an assessment of the earthquake effect based on the observed consequences in the hit area. Hazard maps can be developed in terms of MS intensity, and some examples exist in this respect. In the case of Italy, the last MS hazard map is based on the same seismic source model (known as MPS04) adopted to derive the design seismic actions of the current building code, a study dating more than ten years ago. It provides results in terms of countrywide Mercalli–Cancani–Sieberg (MCS) intensity level with 475 years return period. This short paper presents and discusses MCS probabilistic seismic hazard maps for Italy based on a recent grid-seismicity source model, herein named MPS19, synthetizing the large effort of a wide scientific community. The results, which are obtained by means of classical PSHA, are given in the form of maps referring to the 475 years return period, and also others of earthquake engineering interest. Moreover, it is discussed that the return period does not univocally identifies the MS intensity because, although MS is, by definition, a discrete random variable, it is modelled, in a given earthquake, by means of a normal distribution, that is, treated as continuous. Thus, the maps of the minimum return period causing the occurrence or exceedance of different MCS intensities are also provided. Finally, the comparison between the 475 years return period hazard map presented and the one which is currently the point of reference in Italy, that is, computed using MPS04, is briefly discussed. All the computed maps are made available to the reader as supplemental material.

Integrating macroseismic intensity distributions with a probabilistic approach: an application in Italy

Abstract. The geographic distribution of earthquake effects quantified in terms of macroseismic intensities, the so-called macroseismic field, provides basic information for several applications including source characterization of pre-instrumental earthquakes and risk analysis. Macroseismic fields of past earthquakes as inferred from historical documentation may present spatial gaps, due to the incompleteness of the available information. We present a probabilistic approach aimed at integrating incomplete intensity distributions by considering the Bayesian combination of estimates provided by intensity prediction equations (IPEs) and data documented at nearby localities, accounting for the relevant uncertainties and the discrete and ordinal nature of intensity values. The performance of the proposed methodology is tested at 28 Italian localities with long and rich seismic histories and for two well-known strong earthquakes (i.e., 1980 southern Italy and 2009 central Italy events). A possible application of the approach is also illustrated relative to a 16th-century earthquake in the northern Apennines.

Seismic history of Pel la and the 1st century B.C. earthquake

Research and evaluation of past and recent seismic records is required in order to obtain an overall picture of the seismic history of a given region. To this aim, important information can be collected through the study of monuments and the damage that they may have experienced during their history. Consequently, the archaeological reports on a hitherto unknown earthquake of the Is' century B.C. in Pella (northern Greece) are particularly interesting. These reports are based on the findings that came to light after the excavations of I.Akamatis in the region where the ancient town of Pella was laying. Beginning with this earthquake, this study tries to reach useful conclusions on the seismicity of Pella, in terms of macroseismic intensities from all earthquakes that have affected the town. For all these events, the intensity attenuation relations were used to calculate the macroseismic intensity in Pella. Although it is known a priori that the area is characterized as a relatively low seismicity area, the picture of its seismic history indicates the existence of damaging earthquakes with relatively large return periods. More specifically, in Pella the maximum observed intensity was found to be 7/8 during its seismic history, indicating the picture of low-to-moderate seismic hazard in the region.

Comment on “Total Probability Theorem Versus Shakeability: A Comparison between Two Seismic‐Hazard Approaches Used in Central Asia” by D. Bindi and S. Parolai: Table 1

The recent paper of D. Bindi and S. Parolai (Bindi and Parolai, 2015; hereafter referred to as BP15) considers discrepancies between variants of seismic‐hazard estimates for central Asia. BP15 notes that for this territory the levels of hazard estimated in Ulomov et al. (1999; hereafter referred to as Ul99) during the construction of the Global Seismic Hazard Assessment Program (GSHAP) map shows a clear mismatch when compared with similar maps for neighboring areas: hazard estimates of Ul99 are systematically larger. Indeed, when Zhang et al. (1999) who were responsible for aggregating probabilistic seismic‐hazard assessment (PSHA) maps for various territories of Asia into the single final map tried to combine the component maps, the only way to incorporate the results of Ul99 was to decrease its peak ground acceleration (PGA) values by ∼30%. BP15 discusses the assumption that this problem could be caused by deficiencies of Riznichenko’s hazard estimation procedure, believed to be used in the calculating of Ul99 for GSHAP. The first deficiency under discussion is the implicit assumption of Riznichenko (1965) that the level of shaking, when considered as a function of magnitude M and distance r , can be treated in deterministic style, with no allowance for the scatter of individual observations with respect to an assumed mean relationship. Originally, Riznichenko expressed the level of shaking in terms of macroseismic intensity I , but most of the further discussion is applicable to cases when the level of shaking is expressed in any amplitude measure, further generically denoted A . The need to account for the scatter of I or A is evident (see e.g., Keilis‐Borok et al. , 1973). BP15 comes to the conclusion that their initial guess is untrue: the possible assumption of zero …

Application of SASHA to seismic hazard assessment for Portugal mainland

In the frame of the UPStrat-MAFA “Urban Disaster Prevention Strategies Using MAcroseismic Fields and FAult Sources” project, seismic hazard has been assessed in Portugal in terms of macroseismic intensity. Assessment has been performed by using a probabilistic approach based on the statistical analysis of local seismic histories (i.e., the record of seismic effects at each locality) performed by a new version of the SASHA code (D’Amico and Albarello in Res Lett 79(5):663–671, 2008) on purpose modified to account for this specific area of study. Local seismic histories are reconstructed by considering documented effects or indirect estimates deduced from epicentral information or numerical simulations. All these pieces of evidence are combined taking into account relevant uncertainty and statistical completeness of information locally available. Distribution of expected maximum intensity (i.e., the maximum intensity characterized by a fixed exceedance probability for a exposure time of 50 years) has been obtained and compared with the one deduced from alternative approaches.

Seismic hazard assessment for Iceland in terms of macroseismic intensity using a site approach

We present the results of probabilistic seismic hazard assessment for Iceland in the framework of the EU project UPStrat-MAFA using the so-called site approach implemented in the SASHA computational code. This approach estimates seismic hazard in terms of macroseismic intensity by basically relying on local information about documented effects of past seismic events in the framework of a formally coherent and complete treatment of intensity data. In the case of Iceland, due to the lack of observed intensities for past earthquakes, local seismic histories were built using indirect macroseismic estimates deduced from epicentral information through an empirical attenuation relationship in probabilistic form. Seismic hazard was computed for four exceedance probabilities for an exposure time of 50 years, equivalent to average return periods of 50, 200, 475 and 975 years. For some localities, further return periods were examined and deaggregation analysis was performed. Results appear significantly different from previous seismic hazard maps, though just a semi-qualitative comparison is possible because of the different shaking measure considered (peak ground acceleration versus intensity), and the different computational methodology and input data used in these studies.

Probabilistic seismic hazard assessment for Central Asia

<p>Central Asia is one of the seismically most active regions in the world. Its complex seismicity due to the collision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a hazard assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s<sup>2</sup>. In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic seismic hazard assessment (PSHA) for Central Asia. The seismic hazard is assessed considering shallow (depth < 50 km) seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The seismic hazard is calculated in terms of macroseismic intensity (MSK-64), intended to be used for the seismic risk maps of the region. The hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroseismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of seismic hazard are compared and their underlying methodologies are discussed.</p>

Establishment of Earthquake Intensity Meter Network in the Philippines

A network of realtime intensity meters is being established in different parts of the Philippines under a Japan-Philippines cooperation. The intensity meters can record and transmit on a near real-time basis the site-specific levels of groundshaking in terms of macroseismic intensity, peak ground acceleration and peak ground velocity. The intensity meters evaluate earthquake effects using the Philippine earthquake intensity scale – PHIVOLCS Earthquake Intensity Scale (PEIS). Deployment of the instruments was planned according to an optimum distribution with respect to active earthquake generators and vulnerable communities. All manned seismic stations of PHIVOLCS were equipped with an intensity meter while the rest was deployed in relevant disaster risk reduction and management centers. In its initial operation which started in 2012, the network captured several significant earthquakes such as theMw7.2 in Bohol in 2013.

SP-064 RESULTS OF AUTOLOGOUS PERIPHERAL HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR PATIENTS WITH MULTIPLE MYELOMA WITHOUT MAINTENANCE THERAPY

In the process of updating existing PSHA maps in Central Asia, a first step is the evaluation of the seismic hazard in terms of macroseismic intensity by applying a data driven method. Following the Site Approach to Seismic Hazard Assessment (SASHA) [11], the evaluation of the probability of exceedance of any given intensity value over a fixed exposure time, is mainly based on the seismic histories available at different locations without requiring any a-priori assumption about seismic zonation. The effects of earthquakes not included in the seismic history can be accounted by propagating the epicentral information through a Intensity Prediction Equation developed for the analyzed area. In order to comply with existing building codes in the region that use macroseismic intensity instead of PGA, we evaluated the seismic hazard at 2911 localities using a macroseismic catalog composed by 5322 intensity data points relevant to 75 earthquakes in the magnitude range 4.6–8.3. The results show that for most of the investigated area the intensity having a probability of at least 10% to be exceeded in 50 years is VIII. The intensity rises to IX for some area struck by strong earthquakes in the past, like the Chou-Kemin-Chilik fault zone in northern Tien-Shan, between Kyrgyzstan and Kazakhstan, or in Gissar range between Tajikistan and Uzbekistan. These values are about one intensity unit less than those evaluated in the Global Seismic Hazard Assessment Program (GSHAP; Ulomov, The GSHAP Region 7 working group [29]). Moreover, hazard curves have been extracted for the main towns of Central Asia and the results compared with the estimates previously obtained. A good agreement has been found for Bishkek (Kyrgyzstan) and Dushanbe (Tajikistan), while a lower probability of occurrence of I=VIII has been obtained for Tashkent (Uzbekistan) and a larger one for I=IX in Almaty (Kazakhstan).

Comparison of seismic risk assessment based on macroseismic intensity and spectrum approaches using ‘SeisVARA’

A comparative study of risk assessment methodologies based on macroseismic intensity and response spectrum approaches is presented. To facilitate the comparative study, a spreadsheet-based software tool ‘SeisVARA’ is developed for the estimation of earthquake risk, in which the seismic hazard can be specified either in terms of macroseismic intensity, or peak ground acceleration in combination with the spectral shape and soil amplification model of various earthquake building codes, or in terms of inelastic response spectra using the ‘next generation attenuation relationships’. A comparison of these different approaches is conducted for a typical city in northern India. In addition, the effect of different parameters, e.g., level of PGA, spectral shape, source-site parameters, and soil amplification models, is studied. It is observed that not only the different approaches result in widely varying damage and loss estimates, but also the variation of parameters within a given approach can result in considerable differences.

Probabilistic seismic hazard at Mt. Etna (Italy): The contribution of local fault activity in mid-term assessment

In this work, we tackle the problem of seismic hazard at Etna deriving from the recurrent seismogenic activity of local faults, by adopting two independent methods based on probabilistic approaches. We assess the hazard in terms of macroseismic intensity and represent the occurrence probability calculated for different exposure times both on maps and at fault scale. Seismic hazard maps obtained by applying the “site approach” through the SASHA code and a new probabilistic attenuation model, indicate the eastern flank of the volcano as the most hazardous, with expected intensity (Iexp) in 50years (i.e. the standard exposure time adopted in the seismic regulations) ranging from degrees IX to X EMS. In shorter exposure periods (20, 10, 5years), values of Iexp up to IX are also reached in the same area, but they are clearly determined by the earthquakes generated by the Timpe fault system. In order to quantify the contribution of local seismogenic sources to the hazard of the region, we reconstruct the seismic history of each fault and calculate with SASHA the probability that earthquakes of a given intensity may be generated in different exposure times. Results confirm the high level of hazard due to the S. Tecla, Moscarello and Fiandaca faults especially for earthquakes of moderate intensity, i.e. VI≤I0≤VII, with probabilities respectively exceeding 50% and 20% in 10years, and 30% and 10% in 5years. Occurrence probability of major events (I0≥VIII) at the fault scale has also been investigated by statistics on intertimes. Under stationary assumptions we obtain a probability of 6.8% in 5years for each structure; by introducing the time-dependency (time elapsed since the last event occurred on each fault) through a BPT model, we identify the Moscarello and S. Tecla faults as the most probable sources to be activated in the next 5years (2013–2017). This result may represent a useful indication to establish priority criteria for actions aimed at reducing seismic risk at a local scale.

Seismic hazard assessment in Central Asia: Outcomes from a site approach

In the process of updating existing PSHA maps in Central Asia, a first step is the evaluation of the seismic hazard in terms of macroseismic intensity by applying a data driven method. Following the Site Approach to Seismic Hazard Assessment (SASHA) [11], the evaluation of the probability of exceedance of any given intensity value over a fixed exposure time, is mainly based on the seismic histories available at different locations without requiring any a-priori assumption about seismic zonation. The effects of earthquakes not included in the seismic history can be accounted by propagating the epicentral information through a Intensity Prediction Equation developed for the analyzed area. In order to comply with existing building codes in the region that use macroseismic intensity instead of PGA, we evaluated the seismic hazard at 2911 localities using a macroseismic catalog composed by 5322 intensity data points relevant to 75 earthquakes in the magnitude range 4.6–8.3. The results show that for most of the investigated area the intensity having a probability of at least 10% to be exceeded in 50 years is VIII. The intensity rises to IX for some area struck by strong earthquakes in the past, like the Chou-Kemin-Chilik fault zone in northern Tien-Shan, between Kyrgyzstan and Kazakhstan, or in Gissar range between Tajikistan and Uzbekistan. These values are about one intensity unit less than those evaluated in the Global Seismic Hazard Assessment Program (GSHAP; Ulomov, The GSHAP Region 7 working group [29]). Moreover, hazard curves have been extracted for the main towns of Central Asia and the results compared with the estimates previously obtained. A good agreement has been found for Bishkek (Kyrgyzstan) and Dushanbe (Tajikistan), while a lower probability of occurrence of I=VIII has been obtained for Tashkent (Uzbekistan) and a larger one for I=IX in Almaty (Kazakhstan).

Developing Empirical Collapse Fragility Functions for Global Building Types

Building collapse is the dominant cause of casualties during earthquakes. In order to better predict human fatalities, the U.S. Geological Survey's Prompt Assessment of Global Earthquakes for Response (PAGER) program requires collapse fragility functions for global building types. The collapse fragility is expressed as the probability of collapse at discrete levels of the input hazard defined in terms of macroseismic intensity. This article provides a simple procedure for quantifying collapse fragility using vulnerability criteria based on the European Macroseismic Scale (1998) for selected European building types. In addition, the collapse fragility functions are developed for global building types by fitting the beta distribution to the multiple experts’ estimates for the same building type (obtained from EERI's World Housing Encyclopedia (WHE)-PAGER survey). Finally, using the collapse probability distributions at each shaking intensity level as a prior and field-based collapse-rate observations as likelihood, it is possible to update the collapse fragility functions for global building types using the Bayesian procedure.

Seismic Hazard Assessment in Terms of Macroseismic Intensity in Italy: A Critical Analysis from the Comparison of Different Computational Procedures

Abstract Two probabilistic seismic hazard (PSH) maps in terms of macroseismic intensity characterized by an exceedance probability of 10% for exposure time of 50 years are presented and compared. The first map adopts the standard Cornell–McGuire approach and follows the computational scheme developed for the reference Italian peak ground acceleration (PGA) hazard map (MPS04), while the second one is derived through an alternative methodology (referred to here as the site approach) that is based on statistical analysis of the site seismic history (i.e., macroseismic intensities documented for past earthquakes). Because the two procedures make a different use of available information, this comparison provides a new insight about the sensitivity of PSH estimates for the different possible methodological choices. In particular, it is shown that, though basic differences exist between the two adopted methodologies, relevant results appear consistent over most of Italy. However, at a significant number of investigated localities (Italian municipalities), PSH estimates provided by the site approach are larger than those derived from the standard technique. Thus, a detailed analysis has been carried out to evaluate the role played by different choices of computational models and input data. Among these, the use/nonuse of seismogenic zoning seems to act as the key element in determining the pattern of differences observed between the two PSH estimates.

A macroseismic intensity prediction equation for intermediate depth earthquakes in the Vrancea region, Romania

The use of shake maps in terms of macroseismic intensity in earthquake early warning systems as well as intensity based seismic hazard assessments provides a valuable supplement to typical studies based on recorded ground motion parameters. A requirement for such applications is ground motion prediction equations (GMPE) in terms of macroseismic intensity, which have the advantages of good data availability and the direct relation of intensity to earthquake damage. In the current study, we derive intensity prediction equations for the Vrancea region in Romania, which is characterized by the frequent occurrence of large intermediate depth earthquakes giving rise to a peculiar anisotropic ground shaking distribution. The GMPE have a physical basis and take the anisotropic intensity distribution into account through an empirical regional correction function. Furthermore, the relations are easy to implement for the user. Relations are derived in terms of epicentral, rupture and Joyner–Boore distance and the obtained relations all provide a new intensity estimate with an uncertainty of ca. 0.6 intensity units.

Intensity attenuation in the Campania region, Southern Italy

Ground motion prediction equations (GMPE) in terms of macroseismic intensity are a prerequisite for intensity-based shake maps and seismic hazard assessment and have the advantage of direct relation to earthquake damage and good data availability also for historical events. In this study, we derive GMPE for macroseismic intensity for the Campania region in southern Italy. This region is highly exposed to the seismic hazard related to the high seismicity with moderate- to large-magnitude earthquakes in the Appenninic belt. The relations are based on physical considerations and are easy to implement for the user. The uncertainties in earthquake source parameters are accounted for through a Monte Carlo approach and results are compared to those obtained through a standard regression scheme. One relation takes into account the finite dimensions of the fault plane and describes the site intensity as a function of Joyner–Boore distance. Additionally, a relation describing the intensity as a function of epicentral distance is derived for implementation in cases where the dimensions of the fault plane are unknown. The relations are based on an extensive dataset of macroseismic intensities for large earthquakes in the Campania region and are valid in the magnitude range M w = 6.3–7.0 for shallow crustal earthquakes. Results indicate that the uncertainties in earthquake source parameters are negligible in comparison to the spread in the intensity data. The GMPE provide a good overall fit to historical earthquakes in the region and can provide the intensities for a future earthquake within 1 intensity unit.

Probabilistic seismic hazard assessment for Romania and sensitivity analysis: A case of joint consideration of intermediate-depth (Vrancea) and shallow (crustal) seismicity

The earthquake risk on Romania is one of the highest in Europe, and seismic hazard for almost half of the territory of Romania is determined by the Vrancea seismic region, which is situated beneath the southern Carpathian Arc. The region is characterized by a high rate of occurrence of large earthquakes in a narrow focal volume at depth from 70 to 160 km. Besides the Vrancea area, several zones of shallow seismicity located within and outside the Romanian territory are considered as seismically dangerous. We present the results of probabilistic seismic hazard analysis, which implemented the “logic tree” approach, and which considered both the intermediate-depth and the shallow seismicity. Various available models of seismicity and ground-motion attenuation were used as the alternative variants. Seismic hazard in terms of macroseismic intensities, peak ground acceleration, and response spectra was evaluated for various return periods. Sensitivity study was performed to analyze the impact of variation of input parameters on the hazard results. The uncertainty on hazard estimates may be reduced by better understanding of parameters of the Vrancea source zone and the zones of crustal seismicity. Reduction of uncertainty associated with the ground-motion models is also very important issue for Romania.

Vulnerability index and capacity spectrum based methods for urban seismic risk evaluation. A comparison

This article contributes to the development and application of two latest-generation methods of seismic risk analysis in urban areas. The first method, namely vulnerability index method (VIM), considers five non-null damage states, defines the action in terms of macroseismic intensity and the seismic quality of the building by means of a vulnerability index. The estimated damage degree is measured by semi-empirical functions. The second method, namely capacity spectrum based method (CSBM), considers four no damage states, defines the seismic action in terms of response spectra and the building vulnerability by means of its capacity spectrum. In order to apply both methods to Barcelona (Spain) and compare the results, a deterministic and a probabilistic hazard scenario with soil effects are used. The deterministic one corresponds to a historic earthquake, while the probabilistic seismic ground motion has a probability of exceedence of 10% in 50 years. Detailed information on the building design has been obtained along years by collecting, arranging, improving, and completing the database of the dwellings of the city. A Geographic Information System (GIS) has been customized allowing storing, analysing, and displaying this large amount of spatial and tabular data of dwellings. The obtained results are highly consistent with the historical and modern evolution of the populated area and show the validity and strength of both methods. Although Barcelona has a low to moderate seismic hazard, its expected seismic risk is significant because of the high vulnerability of its buildings. Cities such as Barcelona, located in a low to moderate seismic hazard region, are usually not aware of the seismic risk. The detailed risk maps obtained offer a great opportunity to guide the decision making in the field of seismic risk prevention and mitigation in Barcelona, and for emergency planning in the city.