Global EarthquakE ScEnarios (GEESE): An OpenQuake Engine-Based Rupture Matching Algorithm and Scenarios Database for Seismic Source Model Testing and Rapid Post-Event Response Analysis

Over the past two decades, seismic hazard modeling has advanced along two complementary frontiers: empirical probabilistic frameworks, which systematically capture uncertainty through statistical inference, and physics-based simulation platforms, which directly compute ground motions from the governing equations of wave propagation. This project seeks to unify these two worlds by developing an end-to-end integration between OpenQuake and CyberShake, thereby creating a new generation of seismic hazard models that are globally extensible, probabilistically complete, and physically consistent. CyberShake has been under active development for more than a decade, demonstrating its robustness and scientific maturity through extensive implementations in California. It performs a physics-based probabilistic seismic hazard analysis (PSHA), replacing traditional empirical Ground Motion Prediction Equations (GMPEs) with full 3D numerical simulations of seismic wave propagation. Built upon the UCERF2/3 Earthquake Rupture Forecasts, CyberShake computes hazard curves directly from synthetic seismograms generated via Strain Green’s Tensors and thousands of stochastic rupture variations. This approach enables non-ergodic, site-specific hazard estimation and has set a global benchmark for high-fidelity hazard computation. However, its application has remained geographically limited: both the ERF and 3D velocity models were designed specifically for California, requiring extensive datasets that are rarely available elsewhere. Conversely, OpenQuake, developed by the Global Earthquake Model (GEM) Foundation, provides a fully open-source, Python-based framework for probabilistic seismic hazard and risk analysis. It serves as the computational backbone of large-scale hazard models such as the European Seismic Hazard Model 2020 (ESHM20), which integrates decades of regional expertise into a unified and statistical representation. OpenQuake provides a complete probabilistic framework to build Earthquake Rupture Forecasts (ERFs) that combine declustered catalogs, background seismicity, and multi-branch logic trees, ensuring a balanced and uncertainty-aware representation of regional tectonics. Furthermore, its ecosystem extends seamlessly to vulnerability and exposure modules, enabling the translation of hazard into actionable risk assessments and resilience planning.This project will establish a direct pipeline from OpenQuake’s event-based results to the generation of an ERF compatible with CyberShake’s simulation framework, ensuring moment–rate consistency. By doing so, it will enable CyberShake simulations to be performed for regions beyond California, extending its use to Europe based on the knowledge contained in the ESHM20. The first pilot region is Istanbul, Turkey, a densely populated metropolis located near the western termination of the North Anatolian Fault. Our initial results show that the workflow is already functioning at the prototype level: we have developed a unified 3D velocity model for the Istanbul region by combining available tomographic models with local datasets; generated preliminary event-based rupture catalogs from ESHM20 using OpenQuake; and demonstrated early convergence behavior in hazard curves, indicating that the rupture sampling strategy is statistically robust. These initial results demonstrate the feasibility of the integration approach and indicate that the essential elements needed for a CyberShake-ready ERF are already in place.

Abstract. Seismogenic depth and seismic coupling are important inputs into seismic hazard estimates. Although the importance of seismic coupling is often overlooked, it significantly impacts seismic hazard results. We present an estimation of upper and lower seismogenic depth and expected hypocentral depth and seismic coupling in the transition zone between the Alps, Dinarides and Pannonian Basin, characterized by a complex deformation pattern, highly variable crustal thickness, and moderate seismic hazard, supporting the development of the 2021 seismic hazard model of Slovenia. The hazard model was based on three seismic source models: area source model, fault source model and smoothed seismicity (point) source model. We estimated the lower seismogenic depth using seismological and geological data and compared them. The seismological estimate was based on two regional earthquake catalogues prepared for this study. In the area source model, estimates of lower seismogenic depth from seismological data are deeper or equal to the ones derived from geological data, except in one case. In the fault source model, we analysed each fault individually and chose seismological lower depth estimates in 12 among 89 faults as more representative. The seismogenic thickness for each individual fault source was determined for seismic coupling determination. The seismic coupling was assessed by two approaches, i.e. we chose the most trusted value from the literature, and the value determined for each fault individually by using the approach based on the updated regional fault and earthquake data sets. The final estimate of seismic coupling ranges from 0.77 to 0.38. We compared the tectonic moment rate based on long-term slip rate using different values of seismic coupling with the seismic moment rate obtained from the earthquake catalogue. The analysis is done for the whole area, as well as for the individual area zones. The analysis of N–S components of estimated slip for the largest faults in the area of west Slovenia shows that the regional geological and geodetic shortening rates are comparable. The total activity rate of three global seismic source models is compared, which gives up to a 10 % difference. Our results contribute to a better understanding of the seismic activity in the region. The presented approach for seismic coupling estimation can be applied in cases where the total slip rate is given instead of its seismic part and can be used at regional or national level. The approach is also suitable for the cross-border harmonization of the European seismic hazard modelling data.

Engineers frequently use simplified seismic slope displacement procedures to evaluate the performance of earth structures and natural slopes. Current practices typically adopt Newmark‐type and semi‐empirical seismic displacement prediction models (SDPMs) to estimate the seismic slope displacements ( D ) based on ground motion intensity measures at a given hazard level. In a probabilistic framework, the full range of potential IM values and possible earthquake scenarios are utilized to estimate earthquake‐induced slope displacements for target hazard levels. This study outlines a methodology for deriving probabilistic D values for slopes in Greater Vancouver and the Lower Mainland, incorporating local seismic hazard sources and updates from Canada's 6th‐generation seismic hazard model (CSHM6). A novel computational tool, EqDisp, is developed and used, integrating probabilistic seismic hazard analysis with the calculation of probabilistic permanent displacements ( D ). The study streamlines the process of calculating probabilistic D values for specific locations and site classes, considering various slope characteristics and uncertainties inherent in SDPMs. Using EqDisp, displacement calculations are performed for 264 different sites across Lower Mainland and simplified regional equation is also introduced for direct estimation of the probabilistic displacement values. The significance of probabilistic approaches in generating displacement hazard curves and seismic landslide hazard maps is underscored, enhancing regional assessments of slope stability hazards.

Seismic risk in the form of impending disaster has been seen from past records that moderate-to-large earthquakes have caused the loss of life and property in all parts of Nepal. Despite the availability of new data, and methodological improvements, the available seismic hazard map of Nepal is about two decades old. So an updated seismic hazard model at the country level is imperative and logical. The seismic hazard and risk model constitute important tools for framing public policies toward land-use planning, building regulations, insurance, and emergency preparedness. In fact, the reliable estimation of seismic hazard and risk eventually minimizes social and economic disruption caused by earthquakes. In this frame of reference, the seismic risk assessment at a country level is elementary in reducing potential losses stemming from future earthquakes. Thus, this study investigates structural vulnerability, seismic risk, and the resulting possible economic losses owing to future earthquakes in Nepal. To this end, seismic risk assessment in Nepal is done using an existing probabilistic seismic hazard, a newly developed structural vulnerability, and recently released exposure data. The OpenQuake-engine, the open-source platform for seismic hazard and risk assessment from the Global Earthquake Model initiative, was used to calculate the seismic hazard and risk in Nepal. The seismic hazard and mean economic loss map were formulated for the 1, 2, 5, and 10 % probability of exceedance in 50 years. Finally, the distribution of building damage and corresponding economic losses due to the recurrence of the historical 1934 earthquake was presented in this study.

<p>In the last decade, geodetic data has become fundamental in studies of active faults, seismicity and seismic hazard. In particular, GNSS strain rates and velocities are used to constrain fault-slip rates and seismicity parameters, on the premise that these short-term (ca. 10 yr) measurements are representative of long-term (10<sup>4</sup>–10<sup>6</sup> yr) fault activity. The Western Alps are a good example of such development in a very-low-strain region with a high-density ongoing seismic activity. There, the first-order agreement between GNSS strain rates and earthquake deformation patterns suggest that a large part of the geodetic deformation observed in the area is seismic. This correlation also suggests that geodetic strain rates can provide constraints on seismicity and seismic hazard. With a numerical modeling approach, we point out the similarities between strain rates predicted for Glacial Isostatic Adjustment (GIA) from the Last Glacial Maximum and the geodetic strain rate field, suggesting that a large part of the GNSS signal is related to GIA. However, we show that the apparent compatibility between geodetic strain rates and seismicity hides a strain rate - stress paradox. In fact, stress perturbations due to GIA are not compatible with observed seismicity, and even tend to inhibit fault activity (as observed from focal mechanisms). Thus, the Western Alps present a typical example of a tectonic system where a transient deformation process precludes, or at least strongly complexifies, the use of geodetic strain rates in seismicity and seismic hazard analyses.</p>

Finland, which is characterized by very low seismicity, does not have a national seismic hazard map. However, site specific Probabilistic Seismic Hazard Assessments (PSHAs) for critical infrastructure, including nuclear power plants (NPPs), have been conducted. The sophisticated 2020 European Seismic Hazard Model (ESHM20) offers several advancements that could influence seismic hazard work in stable continental regions like Finland.  As part of the SEISMIC RISK collaborative project involving the University of Helsinki, VTT Technical Research Centre of Finland, and the Geological Survey of Finland, a national PSHA model has been developed. The model is based on a Fennoscandian earthquake catalogue – FENCAT, compiled from Nordic national catalogues based on the observations from the national seismic networks. This allows for calculation of the recurrence parameters with lower magnitudes than the ESHM20. Although a preliminary comparison reveals only minor local differences at hazard levels, a more detailed examination at critical infrastructure sites is necessary. We have compared the regional hazard results obtained within the SEISMIC RISK project and hazard values of the ESHM20 at two NPP sites in Finland. Four criteria from the literature, compiled by Douglas et al. (2023), were employed for assessing the differences between the seismic hazard models. To this end, the mean, median, and 16th and 84th fractiles for the ESHM20 were obtained from the European Facilities for Earthquake Hazard and Risk (EFEHR) database hosted by EPOS–Seismology. A visual inspection of the hazard curves initially indicated consistently higher mean hazards from the Finnish model at the NPP sites compared to ESHM20. The lognormal distributions of the hazard models were estimated, and the differences were assessed for the return periods of 106, 104, 5000, 2475, and 475 years using the four criteria. The distributions revealed a significantly smaller standard deviation for the Finnish model than for the ESHM20. When comparing the two models, the mean Annual Frequency of Exceedance (AFE) changed by over 25% for the ground-motions corresponding to AEFs ≤ 10-4 and by more than 35% for ground-motions corresponding to 10-6 AFE. These findings underline the significant differences between the models.  In summary, a minimum of two out of the four criteria are met at one of the NPP sites, and at the other NPP site, three out of four criteria are satisfied. This further highlights the significance of the differences between the ESHM20 and the Finnish hazard model. Nevertheless, while the observed change in hazard between the Finnish hazard model and the ESHM20 can be deemed substantial, it does not justify the use of the Finnish hazard model for the longer return periods. Further investigations, such as site-specific hazard assessments, are necessary for the return periods relevant to NPPs.        Douglas, J., Crowley, H., Silva, V., Marzocchi, W., Danciu, L., & Pinho, R. (2023). Methods for evaluating the significance and importance of differences amongst probabilistic seismic hazard results for engineering and risk analyses: A review and insights. EGUsphere [preprint], https://doi.org/10.5194/egusphere-2023-991 

Egypt is prone to earthquakes of moderate and strong size from inland and distant seismogenic sources. The seismicity and seismic hazard studies have indicated that the country face moderate seismic hazard. Current practice in the Egyptian building code considers seismic load using seismic input from old seismic zonation map that go back to the late 90’s. Although, this map was developed using a traditional seismic hazard approach, the seismic design strategy, as well as the building code and its update; rely upon it. Also, despite the several developments in the understanding of seismicity, crustal deformation and earthquake mechanics in Egypt that have been achieved in the last two decades, also the presence of theoretical and practical developments, the current seismic load computation of the code is still dangerously adopt and recommend this map. Therefore, the current practice needs an urgent revisit and update. The main aim of this work is to estimate the ground motion parameters in the form of accessible digital maps or databases (e.g. Peak Ground Acceleration, velocity, displacement, response spectra, and time histories) that can be used as input for the next generation of the Egyptian Building code. Physics-based seismic hazard maps and/input are computed where uncertainties are properly evaluated and communicated to the end users. Also, the newly developed maps or input provide a wide range of ground motion parameters in the form of digital databases, not only limited to peak ground motion values, but comprise also excitation records, response spectra or any other ground motion parameter relevant to seismic engineering. The main delivers of this work will be archived and presented using GIS tool that covers whole Egypt with several thousands of sites (nodes), at each node/site. A geospatial database of computed time histories (seismograms and accelerograms) due to all possible seismic sources that can affect those sites are provided. In addition, at each site a representative response spectrum that envelopes all possible ground motion parameters with different percentiles are given.

The Earthquake Model of Middle East (EMME) Project aimed to develop regional scale seismic hazard and risk models uniformly throughout a region extending from the Eastern Mediterranean in the west to the Himalayas in the east and from the Gulf of Oman in the south to the Greater Caucasus in the North; a region which has been continuously devastated by large earthquakes throughout the history. The 2014 Seismic Hazard Model of Middle East (EMME-SHM14) was developed with the contribution of several institutions from ten countries. The present paper summarizes the efforts towards building a homogeneous seismic hazard model of the region and highlights some of the main results of this model. An important aim of the project was to transparently communicate the data and methods used and to obtain reproducible results. By doing so, the use of the model and results will be accessible by a wide community, further support the mitigation of seismic risks in the region and facilitate future improvements to the seismic hazard model. To this end all data, results and methods used are made available through the web-portal of the European Facilities for Earthquake Hazard and Risk ( www.efehr.org ).

A better seismic design for building and other structures is the most effective way to reduce seismic risk and avoid earthquake disaster. Adoption and implementation of new seismic safety regulations and design standards have caused serious problems in many communities in the New Madrid region, including western Kentucky, however. The main reasons for these problems are (1) misunderstanding of the national seismic hazard maps and (2) confusion between seismic hazard and seismic risk. Both are caused by probabilistic seismic hazard analysis (PSHA). PSHA is a mathematical formulation derived from a probability analysis on the distribution of earthquake magnitudes, locations, and ground-motion attenuation. Some assumptions and distributions associated with PSHA have been found to be invalid in earth science, however. In addition, PSHA contains a mathematical error: equating a dimensionless quantity (the annual probability of exceedance – exceedance probability in one year) to a dimensional quantity (the annual frequency of exceedance with the unit of per year [1/yr]). Thus, PSHA is scientifically flawed and the resulting seismic hazard and seismic risk estimates are artifacts. The national seismic hazard curves and maps are artifacts because they were produced from PSHA, even though the inputs are scientifically sound. Although seismic hazard and seismic risk have often been used interchangeably, they are two fundamentally different concepts. Seismic hazard describes the natural phenomenon or property of an earthquake, whereas seismic risk describes the probability of loss or damage that could be caused by a seismic hazard. Seismic hazard and seismic risk play different roles in engineering design and other policy considerations. Furthermore, measures for seismic hazard mitigation are different from those for seismic risk reduction. The difficulties in the development of design ground motion for NEHRP provisions are caused by the use of the national seismic hazard maps which are neither seismic hazard nor seismic risk. The resulting design ground motions for building codes and other policy considerations are therefore problematic. California’s experience proves that deterministic/scenario seismic hazard analysis is an appropriate approach for seismic hazard assessment, seismic risk assessment, as well as *Kentucky Geological Survey, University of Kentucky, 504 Rose Street, Lexington, KY 40506; phone (859) 323-0564; fax (859)257-1147; e-mail: zmwang@uky.edu. 112 Seismic Hazard Design Issues in the Central United States engineering design and other policy considerations. Deterministic/scenario seismic hazard analysis is also appropriate for engineering design and other policy considerations in the New Madrid region, as well as other regions.

A probabilistic seismic hazard analysis of Pakistan is carried out to produce seismic hazard maps showing peak ground acceleration for the 2% and 10% of probability of exceedance in 50 years and spectral acceleration for the 5% and 2% probabilities of exceedance in 50 years. The main objective of this work is to define seismic hazard definition for Pakistan based on the classical approach using updated seismic hazards analysis inputs. A composite earthquake catalogue consisting of 32,700 events was compiled and used in the analysis with a magnitude range of Mw 4.0–8.3. The computations were made at a rectangular grid of 5 km in the OpenQuake engine. Ground motion parameter values have been obtained for flat rock reference seismic site conditions having a shear wave velocity of 760 m/s. Through the logic tree, epistemic uncertainties inherent in ground motion prediction equations and the maximum magnitude potential of seismic sources were estimated. Ground motion prediction equations were assigned equal weights in the logic tree while different weights were assigned to the maximum magnitude potential models. Results of the study were expressed as ground motion contour maps and median uniform hazard spectra for important cities in Pakistan. The results showed that peak ground acceleration values in Pakistan range from 0.16 to 0.54 g for the 10% of probability of exceedance, 0.23–0.72 g for the 5% probability of exceedance and 0.32–1.02 g for the 2% of probability of exceedance in 50 years. Spectral acceleration values at 0.2 s range from 0.67 to 2.19 g for the 2% chance of exceedance in 50 years, respectively, whereas spectral acceleration at 1.0 s ranges from 0.09 to 0.52 g for the 2% chance of exceedance in 50 years. The centre of Pakistan and the southern and the northern region are exposed to high hazard compared to the central-eastern part of the country. Quetta, Chitral, Peshawar, Islamabad Ziarat and Gwadar are exposed to seismic hazard in the PGA range of 0.32–0.45 g. Comparison of the results of this study with those of similar studies suggests that the seismic estimates proposed are reliable. The study provides a demonstration that the classical seismic hazard approach applied here is rational and applicable in Pakistan.

A systematic overview and comparison is presented on the seismic hazard assessment based on the observations and seismic hazard model and the characteristics of earthquake ground motions for a site, a local area, and a region. It shows that the seismic hazard estimated by directly using the observations could differ from that evaluated using an adopted seismic hazard model. It indicates the importance to judiciously select the seismic hazard model, as well as to understand that historical records for a limited period may not fully reflect the seismic hazard. The comparison of the ground motion characteristics is focused on the variability of the ground motion measures, the coherency for record components in two orthogonal orientations, and the spatial correlation and spatial coherency. Procedures for simulating bidirectional excitations at a site and record components at multiple sites for a scenario seismic event are given. The application of the simulated record components to estimate the seismic loss for a portfolio of hypothetical buildings by considering a scenario event is shown, indicating the effectiveness of the presented methodology for seismic loss estimation.

The probabilistic seismic hazard analysis for Romania is revisited within the framework of the BIGSEES national research project ( http://infp.infp.ro/bigsees/default.htm ) financed by the Romanian Ministry of Education and Scientific Research in the period 2012–2016. The scope of this project is to provide a refined description of the seismic action for Romanian sites according to the requirements of Eurocode 8. To this aim, the seismicity of all the sources influencing the Romanian territory is updated based on new data acquired in recent years. The ground-motion models used in the analysis, as well as their corresponding weights, are selected based on the results from several recent papers also published within the framework of the BIGSEES project. The seismic hazard analysis for Romania performed in this study are based on the traditional Cornell-McGuire approach. Finally, the results are discussed and compared with the values obtained in the recently completed SHARE research project. The BIGSEES and SHARE results are not directly comparable since the considered soil conditions are different—actual soil classes for BIGSEES and rock for SHARE. Nevertheless, the analyses of the seismic hazard results for 200 sites in Romania reveal considerable differences between the seismic hazard levels obtained in the present study and the SHARE results and point out the need for further analyses and thorough discussions related to the two seismic hazard models, especially in the light of a possible future harmonized hazard map for Europe.

A seismic hazard and risk analysis is one of the requirements under the Dutch Mining Law when applying for a license for an activity in the deep subsurface. Current methods vary from qualitative to fully probabilistic methods reflecting the level of knowledge and expertise. This paper illustrates the methods used and their treatment of uncertainty.

Spatio-temporal hierarchical cluster analysis of mining-induced seismicity in coal mines using Ward's minimum variance method

Seismic hazard and risk are two very important concepts in engineering design and other policy considerations. Although seismic hazard and risk have often been used interchangeably, they are fundamentally different. Furthermore, seismic risk is more important in engineering design and other policy considerations. Seismic hazard assessment is an effort by earth scientists to quantify seismic hazard and its associated uncertainty in time and space and to provide seismic hazard estimates for seismic risk assessment and other applications. Although seismic hazard assessment is more a scientific issue, it deserves special attention because of its significant implication to society. Two approaches, probabilistic seismic hazard analysis (PSHA) and deterministic seismic hazard analysis (DSHA), are commonly used for seismic hazard assessment. Although PSHA has been proclaimed as the best approach for seismic hazard assessment, it is scientifically flawed (i.e., the physics and mathematics that PSHA is based on are not valid). Use of PSHA could lead to either unsafe or overly conservative engineering design or public policy, each of which has dire consequences to society. On the other hand, DSHA is a viable approach for seismic hazard assessment even though it has been labeled as unreliable. The biggest drawback of DSHA is that the temporal characteristics (i.e., earthquake frequency of occurrence and the associated uncertainty) are often neglected. An alternative, seismic hazard analysis (SHA), utilizes earthquake science and statistics directly and provides a seismic hazard estimate that can be readily used for seismic risk assessment and other applications.