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A fully probabilistic seismic hazard model with a single domain and sufficiently accurate resolution level for national analyses has been developed, for the Caribbean and Central America, to support the design of parametric earthquake policies offered by the Caribbean Catastrophe Risk Financing Facility to sovereign countries. This model provides updated earthquake hazard and risk information for 34 countries in the region, allowing to obtain detailed seismic hazard results at any location within the area of analysis. Besides a detailed zonation of subduction and crustal sources, updated seismicity and tectonic data have been utilized. Different seismicity, geometric, and rupture models have been adopted using state-of-the-art methodologies and tools. The main output of this model is a stochastic event-set, which is the hazard representation utilized not only to compute a long-term overview of the seismic hazard in the region but also to probabilistically estimate earthquake modeled losses at a national level that are used as triggers for underpinning parametric earthquake insurance. Although not of direct interest for parametric insurance purposes, this model also yields hazard maps and uniform hazard spectra for different return periods. For the operational purposes of the parametric insurance coverage, a postevent tool was developed to calculate, in near-real time, the ground-motion intensities associated with any earthquake within the region under study. This is done automatically by choosing a rupture plane from the moment tensor solution based on predefined rules while maintaining full consistency with all the assumptions made in the probabilistic seismic hazard analysis. The predicted ground motions in the region and the vulnerability functions developed for the exposed assets are then used to estimate whether the economic losses for each affected country exceed the trigger value stated in the country-specific insurance policy conditions and whether a payout should be issued, which is typically disbursed within 14 days.

The current practice of Probabilistic Seismic Hazard Analysis (PSHA) considers the inclusion of epistemic uncertainties involved in different parts of the analysis via the logic-tree approach. Given the complexity of modern PSHA models, numerous branches are needed, which in some cases leads to concerns regarding performance issues. We introduce the use of a magnitude exceedance rate which, following Bayesian conventions, we call predictive exceedance rate. This rate is the original Gutenberg–Richter relation after having included the effect of the epistemic uncertainty in parameter β. The predictive exceedance rate was first proposed by Campbell but to our best knowledge is seldom used in current PSHA. We show that the predictive exceedance rate is as accurate as the typical logic-tree approach but allows for much faster computations, a very useful property given the complexity of some modern PSHA models.

A new version of CRISIS, the program to perform probabilistic seismic hazard analysis (PSHA), has been released. This new version, called R-CRISIS v20, includes several additions and improvements with respect to previous ones, in the geometric, attenuation and seismicity models, besides having implemented a parallelized computational process that speeds up the computations up to five times, adding flexibility to the users to perform state-of-the-art PSHA and more complex and detailed analyses within reasonable computational times. These additions have been implemented with the objective of having better representations of the different components of a PSHA whilst preserving all the options that were available in previous versions of the program. R-CRISIS remains being a free and open-source program, two characteristics that combined with its flexible programming architecture provide room for future developments of this mature and widely used tool.

A reliable estimation of seismic hazard-facing Mexico City from local earthquakes has suffered from poor seismic instrumentation, complex crustal structure, large and variable site amplification, and lack of knowledge of recurrence period of earthquakes on the mapped faults. Owing to recent improvement in local seismic networks, an earthquake swarm activity, which occurred in June–August 2019, was well recorded. The largest event of the sequence, an Mw 3.2 earthquake, caused panic in the city and produced peak ground acceleration (PGA) exceeding 0.3g at the closest station (MHVM) about 1 km away. An analysis of the event shows that it had normal-faulting focal mechanism, consistent with northeast–southwest-oriented mapped faults in the region. It was located at a depth of ∼1 km and had a low stress drop (∼0.1 MPa). We find that the high PGA for this low stress-drop event resulted from high-frequency amplification at MHVM (about factor of ∼6 around 13 Hz), likely due to topographic site effects, superimposed on a pervasive broadband amplification of seismic waves at hill-zone sites in the Valley of Mexico (up to ∼10 in the frequency band of 0.2–10 Hz). Simulation of ground motion for a scenario Mw 5.0 earthquake, using an empirical Green’s function technique, reveals that such an event may give rise to significant seismic intensities in the lake-bed zone of Mexico City. The results emphasize the need to re-evaluate the seismic hazard to Mexico City from local crustal earthquakes in the Valley of Mexico.

Rapid post-earthquake loss assessments require as input the ground motion footprint of the event. These footprints account for the geographical distribution of the seismic intensities, which, at the same time, depend on characteristics of the event such as magnitude, location, depth, focal mechanism, and orientation of the fault plane. For most earthquakes with MW ≥ 5, moment tensor solution and, hence, the characteristics of the two nodal-planes are available. This paper proposes a simple set of rules for choosing the likely fault plane from the two nodal planes, based on a previous characterization of the seismic sources in the area under study that are commonly used in probabilistic seismic hazard analyses. With the selection of the fault plane, a critically required information for generating the parametric ground motion footprint is at hand in a matter of minutes, to be later used in the loss assessment phase. These almost real-time loss assessments are useful for different disaster risk management activities ranging from emergency planning and management to triggers of parametric insurance instruments. The application of this methodology is illustrated for three events, two in Mexico and another in Guatemala, where loss results and their geographical distributions at country level in some cases are highly sensitive to the selection of the correct nodal plane as the fault plane, showing that the proposed rules yield congruent results with the observed and recorded ground motions.

In September 2017, two major earthquakes struck south and central Mexico. These earthquakes produced widespread damage in public and private school infrastructure. In Mexico, all school buildings are classified as essential infrastructure and are expected to attain an immediate occupancy performance level after major earthquakes. However, there is a large variation in the quality of the design and construction practices of these buildings due to age of construction, material quality and availability, and great socioeconomic gaps around the country. In this article, an analysis of the observed damage in public school buildings is presented. The results are analyzed depending on the structural system, construction material, and year of construction. The results showed that damage intensity in seismically designed buildings was significantly lower than that observed in the pre-1985 structures. Load bearing and infill masonry walls were the most damaged structural elements.

espanolEl patron y nivel de dano en la region de Mexico Central durante el sismo de septiembre de 2017 Mw7.1 en Morelos-Puebla son diferentes a los observados durante el sismo de Tehuacan (Mw6.9) en 1999 a pesar de que ambos sismos intraplaca tienen magnitudes similares y profundidades focales comparables 57 km y 60 km, respectivamente. El sismo de 2017 causo claramente mas dano en la region de Mexico Central. Los epicentros de ambos eventos estan separados 127 km. Mediante el analisis de los registros sismicos de Mexico Central encontramos que el area expuesta a diferentes niveles de aceleracion maxima del suelo y velocidad maxima del suelo es comparable para los dos eventos. Por ejemplo, el area expuesta a aceleraciones maximas del suelo mayores a 150 cm/s2 es de 12,700 km2 para el sismo de 1999 y 15400 km2 para el sismo de 2017. La forma de los contornos de intensidades y localizacion epicentral sugiere una ruptura bilateral para el evento de 2017 y una ruptura con directividad hacia el norte para el sismo de 1999. Los cocientes espectrales para los dos eventos revelaron una fuente mas energetica hacia el norte para el sismo de 1999 que para el sismo de 2017 lo cual es consistente con resultados reportados previamente de directividad en la ruptura. Se concluye que la distinta localizacion de los dos eventos junto con la diferente distribucion de las poblaciones, monumentos historicos y el incremento de poblacion desde 1999 fueron las principales causas de la diferencia de los danos entre los dos eventos. EnglishThe pattern and level of damage during the 2017 Morelos-Puebla (Mw7.1) earthquake in central Mexico differ from those observed during the 1999 Tehuacan (Mw6.9) earthquake. Although these two intraslab events had similar magnitudes and depths, 57 km and 60 km respectively, the 2017 earthquake caused significantly more damage in central Mexico. The epicenters of the two events were separated by 127 km. From the analysis of strong-motion recordings in central Mexico, we find that the areas within different PGA and PGV contours during the two earthquakes are roughly equal. For example, PGA contour of 150 cm/s2 encloses 12,700 km2 and 15,400 km2 during the 1999 and 2017 events, respectively. The shape of the contours and the location of the epicenter suggests a bilateral rupture during the 2017 earthquake and a rupture directivity to the north for the 1999 earthquake. Spectral ratios of the two earthquakes reveal a more energetic 1999 source to the north than that of 2017 which is consistent with the previously reported rupture directivity. This leads us to conclude that the distinct locations of the two earthquakes along with uneven density of population, dwellings, and historical monuments, and demographic increase since 1999 were the principal causes of the difference in damage during the two earthquakes.

We use accelerograms, seismograms, and data from sparse continuous Global Positioning System (GPS) and campaign-mode GPS stations, deployed along the Pacific coast of Mexico, to study scaling of horizontal peak ground displacement (PGD) with seismic moment (M0) in the epicentral zone above the Mexican subduction thrust. The thrust interface is located at a depth of ∼25 km below the coast. We select recordings with (S–P) time ≤5.9 s (R≤46 km) and reduce the amplitudes to (S–P) time of 3.2 s (R = 25 km). The dataset consists of 58 events and covers a M0 range of 1013–1021 N·m. We find that the double integration of accelerograms, using piecewise linear detrending schemes, leads to sufficiently accurate estimation of PGD to study the scaling relation. The sparse data for great earthquakes are complemented with theoretical static displacement computed using the model of Okada (1992). For earthquakes with M0≤1.26×1018 N·m (Mw≤6.0) the point-source, far-field approximation holds, and the PGD data follows theoretically expected M02/3 scaling. For great earthquakes (M0>1.26×1021 N·m; Mw>8.0), static offset (which is approximately equivalent to PGD) scales as M01/3. About two-thirds of the observed PGD data fall within a factor of 0.67 and 1.5 of the relation given above. The relationship may be useful in earthquake engineering as well as for rapid estimation of magnitude for early tsunami alert.

PurposeThe development of multi-hazard risk assessment frameworks has gained momentum in the recent past. Nevertheless, the common practice with openly available risk data sets, such as the ones derived from the United Nations Office for Disaster Risk Reduction Global Risk Model, has been to assess risk individually for each peril and afterwards aggregate, when possible, the results. Although this approach is sufficient for perils that do not have any interaction between them, for the cases where such interaction exists, and losses can be assumed to occur simultaneously, there may be underestimation of losses. The paper aims to discuss these issues.Design/methodology/approachThis paper summarizes a methodology to integrate simultaneous losses caused by earthquakes and tsunamis, with a peril-agnostic approach that can be expanded to other hazards. The methodology is applied in two relevant locations in Latin America, Acapulco (Mexico) and Callao (Peru), considering in each case building by building exposure databases with portfolios of different characteristics, where the results obtained with the proposed approach are compared against those obtained after the direct aggregation of individual losses.FindingsThe fully probabilistic risk assessment framework used herein is the same of the global risk model but applied at a much higher resolution level of the hazard and exposure data sets, showing its scalability characteristics and the opportunities to refine certain inputs to move forward into decision-making activities related to disaster risk management and reduction.Originality/valueThis paper applies for the first time the proposed methodology in a high-resolution multi-hazard risk assessment for earthquake and tsunami in two major coastal cities in Latin America.

Two new estimators of parameters λ0and β of the Gutenberg-Richter seismicity relation are presented for the case in which several complete portions of an earthquake catalog are used in the estimation process. These estimators are the ones that maximize the joint likelihood of both parameters, considering Poisson arrivals. Therefore, as shown in this paper, they are more robust than estimators previously presented in the literature. The numerical effort to compute the new estimators is greater than with previously published formulas because the new method requires solution of an implicit algebraic equation, for which we provide an iteration strategy of fast convergence. In our opinion, the extra effort is warranted in view of the usual scarcity of data and in view of the extra precision that the new method brings.

In this paper we present an analytical solution for the Bayesian update of ground motion estimates using macroseismic intensity (MI) observations. This solution builds on an earlier work of Ebel and Wald (Earthq Spectra 19:511–529, 2003), who proposed a discrete version of the updating problem. We show that the updated probability distribution of the ground motion has the logarithm of the median that is the weighted average of the respective logarithms of its prior value and a value computed with a ground motion-MI relation, with weights that are proportional to the predictive power of each source of information, measured with its corresponding variance. We also show that the posterior standard deviation is always smaller than the prior. In our opinion, besides its numerical simplicity, the solution presented here allows for a much clearer view of the role that the different parameters play.

It is a common practice to describe the activity of a seismogenic source using Gutenberg–Richter magnitude–frequency relation. The use of this relation includes the statistical determination of three parameters, two of which will be discussed in this paper: the exceedance rate of a threshold magnitude and the rate of decay of the exceedance rate with magnitude. The third parameter, M max , which defines the maximum assumed magnitude, will not be treated here. Due to the methods used to estimate the values of these parameters under certain circumstances, their statistical estimators turn out to be correlated. In this paper we explore: (1) the impact of this correlation on seismic hazard for some simple, canonical cases; and (2) practical ways in which this correlation can be propagated through the seismic hazard calculations. We conclude that the impact of correlation on seismic hazard estimates is moderate and that ignoring correlation is frequently a conservative decision. Also, we propose a way in which correlation can be propagated into seismic hazard calculations within the framework of logic trees.

La versión vigente de las Normas Técnicas Complementarias para Diseño por Sismo (NTCDS) del Reglamento de Construcciones del DF fue desarrollada entre 1999 y 2000, y fue promulgada en 2004. De entonces a la fecha se han llevado a cabo diversas investigaciones que, junto con ideas de cambio que han ocurrido en el mundo, han permitido desarrollar una nueva versión de las NTCDS que posiblemente entrarán en vigor en 2016.En el presente trabajo se describen algunas de las modificaciones más novedosas, de entre las que destacan: a) una nueva “nanozonificación” sísmica que permite obtener espectros de diseño de sitio para casi todo el Distrito Federal; b) la inclusión de los cambios observados en las propiedades de los suelos por efecto del bombeo de agua; y c) los nuevos criterios para la especificación de sobreresistencia y reducciones por ductilidad. En adición, se discute la estructura general de la nueva norma y se reflexiona sobre las ventajas y limitaciones de las modificaciones propuestas.

This paper proposes an earthquake-event-based method for the construction of regional flood hazard maps for tsunami. The method involves five steps. The first is to characterise the seismic hazard as a set of collectively exhaustive and mutually exclusive stochastic events that fully describes the spatial distribution and annual frequency of occurrence in accordance with the location of an earthquake, its depth and magnitude. The second is to compute the vertical sea-floor deformation produced by each one of the earthquakes, after which the propagation of tsunami and the inundation depth produced by each earthquake is calculated. Step four is to present the earthquake-induced tsunami hazard considering only those events that could generate a tsunami as a set of stochastic events that describes the spatial distribution of each tsunami. The final step is to obtain, for any point of interest, the tsunami inundation depth exceedance rate, taking into account the contribution of all tsunamis computed in step four. The method is applied to obtain maps of tsunami hazard for the Mexican Pacific coast for return periods of 150 and 500 years.

The final publication is available at Springer via http://dx.doi.org/10.1007/s10518-018-0516-4 Risk assessment and management is an important step towards resilient and sustainable cities. Among many other perils, both natural and manmade, seismic risk is a major threat for resilience and sustainability. In recent decades, several methods for seismic risk assessment have been proposed, including the well-known Vulnerability Index Method (VIM). In this study, a probabilistic version of the VIM, which we call the Vulnerability Index Method-Probabilistic (VIM_P), is proposed. The VIM_P requires essential information on the seismic hazard and on the vulnerability of the building stock. Seismic hazard is determined using the exceedance rates of macroseismic intensities, as defined in the European Macroseismic Scale (EMS). Seismic vulnerability is defined by means of vulnerability probability density functions (pdf) that describe the probability distribution of the corresponding vulnerability index. Beta-like functions are used for these pdfs. VIM_P quantifies seismic vulnerability by means of three vulnerability curves, Lower, Best and Upper, according to the quantity and quality of available information, thus allowing three estimates of seismic vulnerability and risk. Then, seismic risk is computed via the convolution of seismic hazard and seismic vulnerability, considering semi-empirical damage functions. Seismic risk is given through the exceedance frequencies of the damage grades. To highlight the capabilities of the VIM_P, the seismic risk of about 70,000 residential buildings in Barcelona was assessed. According to the results, the exceedance frequency of the collapse damage state for more than the 50% of the buildings in the Eixample district would be greater than 1 × 10-5. This confirms the relatively high seismic risk in the city, mainly due to the high vulnerability of the built environment. Specific software, USERISK20015, has been developed for routine applications of VIM_P. It is hoped that VIM_P and this new tool for seismic risk assessment will be useful to stakeholders and civil protection authorities for risk management and prioritizing actions that can help to create more resilient, sustainable cities.

This paper concerns with the problem of stabilisation of inertial coupling electromechanical system. The concept of inertial coupling electromechanical system is an interesting topic from the control theory point of view and its universe of applications. This is because, for stabilisation proposes, the complete model of electromechanical system significantly reduces higher frequency functions in their dynamics caused by high gain controllers. Here, the system stabilisation is achieved by applying nonlinear time-varying controllers. The reason to use a time-varying controller is to give some learning or adaptation in the control process. Moreover, to get a good result for the closed-loop system, the structure of a storage function is based on the classical quadratic function in addition to quadratic function of system total energy. So, the main goal of this paper is obtain a controller that guarantees that the system state error arrives near the required equilibrium in exponential form. Hence, the ...

Probabilistic seismic hazard analysis (PSHA) is, in essence, a method to deal with uncertainty, the importance of which justifies the use of a formal and rigorous background for its study. Therefore, the purpose of this paper is to contribute to the reflections on how to correctly handle uncertainty in PSHA. We start by studying the simplest case, a Poisson process in which only “aleatory” uncertainty exists; then, we remove the Poisson hypothesis and find expressions for the occurrence probabilities of earthquakes in given time frames for general non-Poisson processes. Later, we include a simple variety of epistemic uncertainty and show that the resulting process is not Poissonian anymore, so computation of probabilities has to be made taking into account this fact. Next, we give a rigorous rule to combine uncertainties of aleatory and epistemic origin, which gives reasonable criteria to decide whether the epistemic uncertainty is large or not. Also, we propose unambiguous guidelines to decide whether a particular class of uncertainty has to be included in the hazard calculations as epistemic or as aleatory. Finally, we discuss the problem of how our estimates could differ if we wrongly considered that our epistemic uncertainty is of aleatory nature, or vice versa.

A new approach is proposed for the probabilistic financial risk assessment of earthquake-induced tsunami. The risk is evaluated in a probabilistic framework for a full set of hazard events including all uncertainties. The hazard is defined as a stochastic and historic set of events, collectively exhaustive and mutually exclusive, that describes the spatial distribution, the annual frequency and the randomness of the hazard intensity. The risk is expressed as losses in different terms: the average annual loss and the loss exceedance curve. These metrics are of particular importance for risk financing schemes and risk transfer instruments. As an illustrative example, this approach is applied to the probabilistic tsunami risk assessment for public schools in southern Mexico.

In this paper, a parameter estimation for a class of second order nonlinear system is presented. The considered system, can be represented in such way that it is linear respect its parameters. Since the system output is given, only, for the second integrator a state estimation of unmeasured state variables is reconstructed via nonlinear observer based on the terminal sliding mode observer. Therefore, the main contribution of this paper deals with a full order nonlinear observer algorithm design to enhance parameter identification of a nonlinear second order system. Finally, to illustrate the theoretical performance of the proposed identification algorithm, an experimental result of a mechanical system is presented.

The knowledge of seismic risk of buildings can contribute to increase the resilience of cities. In the present work a new assessment of the seismic risk of dwelling buildings of Barcelona was done. This assessment was performed according to a probabilistic methodology, which is summarized in the following steps: (1) performing a probabilistic seismic hazard assessment (PSHA) to obtain exceedance rates of macroseismic intensities; (2) performing a probabilistic seismic vulnerability assessment (PSVA) of each building in order to determine probability density functions that describe the variation of a vulnerability index; and (3) performing a probabilistic seismic risk assessment (PSRA) to generate seismic risk curves in terms of frequencies of exceedance of damage states. In the present work 69,982 dwelling buildings of Barcelona were assessed. According to the results the percentage of dwelling buildings of Barcelona that have a probability equal or greater than 1% of suffer partial collapse in the next 50 years is a value between 0% and 34.29%. A value of 0% corresponds to the results of seismic risk obtained for the case where regional vulnerability modifiers were not considered during the procedure to assess the seismic vulnerability of buildings and 34.29% correspond to the case where regional vulnerability modifiers were considered. For the same two options, the losses due to the physical damage of the dwelling buildings of Barcelona assessed for an exposure time of 50 years, could vary from 807.3 to 1739.4 millions of euros, respectively. Finally, possible uses of the seismic risk results computed in the present work are mentioned.

One of the most common ways to represent results of the probabilistic seismic hazard assessments (PSHA) are maps of seismic hazard, which usually show values of Peak Ground Acceleration (PGA) in a region for a return period. A common return period is of 475 years. These types of maps are frequently incorporated in seismic codes, which include the minimum requirements to design new buildings. On the other hand, a sensitivity analysis usually gives us additional information about a procedure or result. For instance, a sensitivity analysis about a PSHA can give us information about what variables considered to compute the seismic hazard have a significant influence on the results of seismic hazard. In the present study, we performed a sensitivity analysis related to the PSHA for Barcelona. This analysis was oriented to identify the influence in the results of seismic hazard of the following variables: a) the relationship magnitude-macroseismic intensity chosen to convert values of macroseismic intensity to magnitudes; b) the beta parameter that was used to define part of the seismicity of a seismic source and; c) the ground motion prediction equation (GMPE) which was used to determine intensities values to different distances from the epicenter of earthquakes. For this purpose, we applied the code R-CRISIS, which is the updated version of CRISIS2015. Therefore, the present study had as an additional objective to test the functionality of the new R-CRISIS from the point of view of users. According to the results of the sensitivity analysis of the PSHA of Barcelona both the GMPE and the relationship magnitude-macroseismic intensity are the two variables that have the greater influence on the results of seismic hazard of the present study. For instance, in some results of seismic hazard for the city of Barcelona the values of PGA (for the same return period) differ between them until 82% depending on if we considered the means values of the PGA values of the GMPE or the mean values plus one standard deviation of the PGA values of the GMPE. Finally, according to our experience in the use of the new R-CRISIS in the present study, we can confirm that it is both a powerful and user-friendly software. R-CRISIS has valuable features, for instance, it allows to consider diverse types of criteria to define the type of seismic source. For example, R-CRISIS allows defining different types of geometries of the seismic sources, and different criteria to define the seismicity of each seismic source. An important feature of R-CRISIS is the fact that it includes a database with numerous GMPE ready to be used to compute seismic hazard. Additionally, R-CRISIS has valuables graphical tools which are very helpful during the following two stages: the assigning data and the analysis of results.

The final publication is available at Springer via http://dx.doi.org/10.1007%2Fs11069-017-3087-9 Among the activities developed under the framework of the Global Earthquake Model, the development of a global consequences database was included. This was defined with the objective of serving as public repository of damages and losses, occurred on different types of elements because of a selected list of earthquakes with epicentres at varying locations around the globe, but also to be used as a benchmark for the development of vulnerability models that capture specific characteristics of the building typologies in each country. The online earthquakes consequences’ database has information on 71 events where 16 of them occurred in the Latin America and the Caribbean Region. A complete and comprehensive review and data gathering process were developed for these selected earthquakes accounting for different aspects and dimensions that were considered of interest, besides the physical damage, such as casualties, socio-economic implications, damages and disruptions in critical facilities and infrastructures, together with the occurrence of secondary events triggered by the ground shaking such as landslides and tsunamis. When possible, the damage and casualties were geo-located using a standardized approach and included in the database. The contributions of the Latin America and Caribbean Region to the database were at the same time a challenge and an opportunity to collect, review, put together and standardize, up to a certain point, damage data of previous earthquakes additionally of being a step forward in the field of open data.

The consideration of environmental losses in seismic design is discussed within the framework of cost optimization analysis. Within this context, the equivalent carbon emissions (CO2-e) are used as a proxy for the environmental cost related to seismic damage, and a model to assess the environmental cost in seismic loss estimation is introduced. The use of the model is illustrated through its application to the analysis of simple earthquake-resistant structural systems. It is concluded that under certain circumstances, the consideration of environmental issues in seismic design may be important, especially as the planning time horizon of the facility increases.

We study the relative importance of interplate and intraslab earthquakes in the seismic hazard of Mexico City by analyzing accelerograms recorded at the hill-zone site of CU (1964–2012) and the lake-bed site of SCT (1985–2012). Amaxexceeded 6 gal during 20 earthquakes at CU during this period. Of these, eight were intraslab events so that the exceedance rate of Amax≥ 6 gal from both types of earthquakes is roughly about the same. The estimated return period of Amaxof 30 gal from the two types of earthquakes is ∼100 yrs. If we consider high-frequency (2.5–8.5 Hz) acceleration ( AmaxHF) at CU, then the top 7 out of the 20 events are all intraslab earthquakes. Even at the lake-bed site of SCT, the AmaxHFvalues are, generally, associated with intraslab earthquakes. It follows that the risk from both types of earthquakes to low-rise construction in the city needs careful assessment.

An event-based approach for the probabilistic risk assessment of agricultural drought under rainfed conditions to estimate the economic impact is proposed. The risk parameters are evaluated in an event-based probabilistic framework for a set of hazard events; these results are probabilistically integrated including, in a formal way, all uncertainties related to every part of the process. The hazard is defined as a stochastic or historic set of events, collectively exhaustive and mutually exclusive, that describes the spatial distribution, the annual frequency, and the randomness of the hazard intensity. The risk is expressed in different economic terms: the average annual loss (or pure risk premium) and the loss exceedance curve; these metrics are of particular importance for risk retention (financing) schemes or risk transfer instruments. As an illustrative example, this approach is applied to probabilistic drought risk assessment of maize under rainfed conditions in Mexico. These results are the base of further studies in defining strategies for financial protection against agricultural losses and disasters.

In the framework of the UNISDR׳s Global Assessment Report on Disaster Risk Reduction 2013, for the first time, a fully probabilistic seismic hazard assessment was conducted at global level, using the same methodology for the whole Globe, from which a set of stochastic scenarios for different intensities (spectral accelerations, 5% damping) was obtained and then used in a fully probabilistic risk analysis. First, the Globe was divided into a set of seismogenetic areas to which a maximum magnitude and a predominant tectonic environment type were assigned. A Gutenberg-Richter magnitude-frequency distribution was assumed for each region, with a and b-values computed using a smoothed-seismicity procedure based on the NEIC11 National Earthquake Information Center. -USGS22 United States Geological Survey seismic catalog. This catalog was first subjected to a declustering process and completeness verification for several threshold magnitudes. Based on the tectonic environment assigned to each source, a ground motion prediction model was assigned accordingly. Probabilistic hazard computations were performed with program CRISIS 2012, which generated conventional hazard curves for different intensities and maps for various return periods, as well as a set of stochastic scenarios compatible with the CAPRA33 Comprehensive Approach to Probabilistic Risk Assessment platform. These scenarios, in turn, were used to perform coarse-grain probabilistic risk computations.

"La Faja Volcánica Transmexicana (FVTM) es una cadena volcánica activa que se deforma por una red de fallas extensionales intraarco. Aunque varios sismos corticales con magnitud>7 se han originado en la FVTM desde el siglo XVI, la sismicidad de fondo de esta estructura geológica es muy baja y la región es considerada, tradicionalmente, como de peligro sísmico bajo. En este estudio, presentamos un modelo probabilístico actualizado de la FVTM. El catálogo de sismicidad empleado incluye cuarenta y tres sismos registrados histórica e instrumentalmente desde 1858 hasta 2014; 5 de los cuales, son eventos de magnitud considerable ocurridos en la FVTM a lo largo del siglo XIX. Debido a la falta de una muestra estadísticamente representativa, proponemos, de manera cualititativa, que dicho catálogo es completo para magnitudes M≥4 desde 1964 y, para magnitudes M≥6; desde 1858. De igual modo, introducimos tres diferentes relaciones de magnitud-frecuencia entre eventos. La primera, es una relación convencional Gutenberg-Richter que ajusta la distribución de sismos registrados de manera instrumental. Las dos restantes, son aproximaciones semiparamétricas que integran datos históricos e instrumentados para determinar tasas de sismicidad en la región. Nuestro modelo preferido (modelo de sismicidad B) ajusta la distribución de datos históricos e instrumentados de manera independiente y otro lado, presentamos un mapa de peligro uniforme (USH) de la FVTM para un periodo de retorno de 500 años que se obtiene considerando tres fuentes sísmicas principales: 1) Sismos de subducción con fallamiento inverso originados en la Trinchera Mesoamericana (MAT); sismos de profundidad intermedia generados dentro de la subyacente Placa de Cocos y 3) sismos de naturaleza cortical localizados en la FVTM. De acuerdo con el modelo de sismicidad B, el periodo promedio de recurrencia de sismos M≥7 en la FVTM es, aproximadamente, 150 años. En contraste, el periodo de recurrencia calculado usando exclusivamente datos instrumentados es de 12,000 años. Los resultados de este modelo de sismicidad, que considera datos históricos e instrumentales, parecen coincidir con los periodos de retorno de sismos prehistóricos estimados para pequeños segmentos del sistema de fallas de la FVTM reportados en diversos estudios paleosismológicos. Al comparar los resultados de nuestro modelo de sismicidad predilecto, los valores de PGA obtenidos a partir de datos de sismicidad instrumentada son entre 18 y 56% menores que aquéllos predichos por el modelo de sismicidad que también considera el catálogo de sismicidad histórica."

La mañana del 19 de septiembre de 1985, la Ciudad de México amaneció con fuertes y prolongados temblores de tierra. El origen del movimiento fue un sismo ubicado aproximadamente a 350 km al suroeste de la ciudad, en la zona de subducción a lo largo de la costa del Pacífico de México. Cuando las oscilaciones de la cuenca amainaron, luego de un período anormalmente largo de aproximadamente cuatro minutos de fuertes sacudidas, la parte central de la ciudad mostró daños sin precedentes, imprevistos y, en ese momento, incomprensibles.doi: sin doi

A simple model is presented to combine, using a probabilistic approach, the losses arising from several hazards that are triggered simultaneously by the same event. The merits of the model are presented, demonstrating the intuitive appeal of this combination rule. Assuming that the losses due to individual hazards are conditionally independent random variables with known mean and variance, expressions are given to compute the mean and variance of the combined loss. Finally, an approximate method is given to construct the probability distribution of this combined loss.

In current practice of probabilistic seismic‐hazard analysis (PSHA), the difference between ground‐motion prediction equations (GMPEs), which are in principle equally valid related to their quality and applicability, is attributed to epistemic uncertainty. The standard practice is to include this uncertainty through logic trees. Based on probability concepts, we present a method to assist during the selection and weighting of GMPEs to be included in different branches of a logic tree. We find that in regions with abundant recorded data, only those models with large likelihood should be considered. Although the presented method is not the only option to define the weighting of GMPEs for PSHA, it offers an ordered way to combine different sources of knowledge, such as recorded data and prior information.

Within the framework of performance‐based earthquake engineering, the intensity‐measure approach (IMA) has become the standard option for the characterization of engineering‐demand parameters (EDPs) for systems undergoing significant inelastic behavior. Within this approach, the rates of exceedance of the EDPs are computed from a hazard curve corresponding to an intensity measure (IM; usually the spectral acceleration at the first mode period S A ( T 1 )) and the conditional probability density function (CPDF) of the EDP given the IM. In view of the lack of strong ground motion records associated with large values of currently used IMs, the parameters required to establish a CPDF are obtained from an incremental dynamic analysis that considers the S A ( T 1 ) linear scaling of motions recorded during seismic events of moderate intensity. However, from a seismological perspective, the linearly scaling method is too simple and may lead to unrealistic ground‐motion records that may affect the accuracy of the IMA. The dynamic response of single‐degree‐of‐freedom systems subjected to simulated ground motions is analyzed in order to assess the limitations of the S A ( T 1 ) linearly scaling method. These simulated ground motions were obtained via a stochastic simulation technique that has a solid seismological basis. The results presented herein are useful to numerically understand the limitations of the S A ( T 1 ) linearly scaling method and to identify situations in which a more sophisticated analysis is warranted.

An event-based approach for probabilistic flood risk assessment for financial and civil protection applications is proposed. The risk parameters are evaluated in an event-based probabilistic framework for a set of hazard events and then all these results are probabilistically integrated, including, in a formal way, all uncertainties related to each and every part of the process. The hazard is defined as a stochastic or historic set of events, collectively exhaustive and mutually exclusive, that describes the spatial distribution, the annual frequency, and the randomness of the hazard intensity. The risk is expressed in different economic terms: the average annual loss, the pure risk premium, and the loss exceedance curve. As an illustrative example, this approach is applied to Acapulco city located on the Pacific coast of Mexico. These metrics are of particular importance for risk retention (financing) schemes or risk transfer instruments, and, therefore, they will be a particularly valuable contr...