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The recent high death tolls caused by large earthquakes are a further indication that earthquakes remain one of the most destructive natural disasters in the world and can seriously threaten the achievement of sustainable development goals. To effectively reduce the existing seismic risk, the limited available mitigation resources should be allocated to areas where the potential risk is most severe. However, such areas are typically uncertain and difficult to locate. Here, we propose a strategy to delineate regional high seismic risk zones at a fine resolution and with high confidence. Our analyses reveal that the delineated zone accounts for only ~7% of the regional land area but for ~85% of the total financial loss. We recommend that seismic risk mitigation measures be prioritized in such high-risk zones, especially for densely populated cities in seismically active areas, to better meet the disaster risk reduction targets in the Sendai Framework.

Despite global efforts to reduce seismic risk, earthquake remains one of the most destructive natural disasters in the world, especially for seismic active zones when they are characterized by high densification of fixed assets and population. For a specific country or region, the most effective way to achieve earthquake resilience is preparedness prior to an earthquake. To mitigate potential seismic risk, it is important to understand where high seismic risk zone locates, since the budgetary resources available from the local government are always limited and they should be allocated to such zone with priority. This paper proposes a strategy to delineate regional high seismic risk zone by combing different seismic risk assessment results, aiming to make the seismic risk mitigation practice more targeted and operable. Our analyses show that while the delineated high seismic risk zone occupies only ~10% of the case study area, it accounts for ~90% of the total seismic risk in terms of economic loss. To achieve more targeted seismic risk mitigation, we recommend that such zone should be given top priority in seismic risk mitigation.

As part of the NARSIS (New Approach to Reactor Safety ImprovementS, www.narsis.eu) project, and the MYRIAD-EU (Multi-hazard and sYstemic framework for enhancing Risk-Informed mAnagement and Decision-making in the EU, www.myriadproject.eu) project, a compendium of existing open access software packages for risk modelling of natural hazards, as well as a review of multi-hazard projects has been undertaken with a clear focus on assessments in Europe.There have been over 200 open access software packages produced for the evaluation of singular natural hazards, combinations of natural hazards and multi-hazard identified either propagating through to risk, or calculating extensive hazard metrics. By far, the most have been built for floods, and earthquakes, however a number have been designed for multi-hazard (RiskSCAPE, HAZUS and variants, CLIMADA, NARSIS-MHE, InaSAFE to name a few).In around 120 of them, they have moved through to risk assessment, with the calculation of risk metrics. Many of these have been designed for scenario analysis, but there are also many which employ probabilistic methods or stochastic models to evaluate risk. In this work, the classification of the open access software packages follows that of previous studies (Daniell et al., 2014), but with a focus on the use for multi-hazard assessment rather than singular hazards.Moving through to multi-risk, a number include different interconnected systems for assets (OOFIMS for instance from the EU SYNER-G project). Although there are very few that deal with consecutive or coinciding hazards, a number can be adapted to do this, and some even have the ability to be used for cascading hazard analysis.By understanding the state-of-the-art in existing software packages as of 2022, a multi-hazard framework can be produced for various economic sectors such as ecosystems and forestry, energy, finance, food and agriculture, infrastructure and transport, as well as tourism, to solve some of the missing links when looking at the impacts of consecutive, coinciding or cascading hazards. In addition, relevant software packages have been found to conduct assessments on the European scale, but also on the local scale for more detailed analyses.

Residual risk exists in our buildings even if they were designed in conformance with modern codes of practice. Various approaches have been implemented or proposed in the last decade for setting risk-based performance requirements for seismic design of building structures. However, there is insufficient consideration about the aggregated risk for society, which could be significant especially for a densely populated metropolitan city. This paper introduces a rational and universal approach for evaluating the adequacy of structural safety requirements by comparing societal risk functions based on probabilistic loss assessment with a proposed regulatory requirement that aims to limit the mortality rate to “as low as reasonably practicable (ALARP)”. The proposed approach is then applied to Melbourne, Australia, in a case study, which shows that the earthquake fatality risk for the society appears to be unacceptable. The outcome can be used for justification of a seismic retrofitting policy or a required change of the design code level. The proposed scheme is also applicable to other natural hazards and for safety engineering applications generally.

Previous seismic damage reports have shown that the damage and collapse of buildings is the leading cause of fatality and property loss. To enhance the estimation accuracy of economic loss and fatality in seismic risk assessment, a high-resolution building exposure model is important. Previous studies in developing global and regional building exposure models usually use coarse administrative level (e.g., county, or sub-country level) census data as model inputs, which cannot fully reflect the spatial heterogeneity of buildings in large countries like China. To develop a high-resolution residential building stock model for mainland China, this paper uses finer urbanity level population and building-related statistics extracted from the records in Tabulation of the 2010 Population Census of the People’s Republic of China (hereafter abbreviated as the “2010-census”). In the 2010-census records, for each province, the building-related statistics are categorized into three urbanity levels (urban, township, and rural). Statistics of each urbanity level are from areas with a similar development background but belong to different administrative prefectures and counties. Due to privacy protection-related issues, these urbanity level statistics are not geo-coded. Therefore, before disaggregating these statistics into high-resolution grid level, we need to determine the urbanity attributes of grids within each province. For this purpose, the geo-coded population density profile (with 1 km × 1 km resolution) developed in the 2015 Global Human Settlement Layer (GSHL) project is selected to divide the 31 provinces of mainland China into 1 km × 1 km grids. Then for each province, the grids are assigned with urban/township/rural attributes according to the population density in the 2015 GHSL profile. Next for each urbanity of each province, the urbanity level building-related statistics extracted from the 2010-census records can be disaggregated into the 2015 GHSL geo-coded grids, and the 2015 GHSL population in each grid is used as the disaggregation weight. Based on the four structure types (steel/reinforced-concrete, mixed, brick/wood, other) and five storey classes (1, 2–3, 4–6, 7–9, ≥ 10) of residential buildings classified in the 2010-census records, we reclassify the residential buildings into 17 building subtypes attached with both structure type and storey class and estimate their unit construction prices. Finally, we develop a geo-coded 1 km × 1 km resolution residential building exposure model for 31 provinces of mainland China. In each 1 km × 1 km grid, the floor areas of the 17 residential building subtypes and their replacement values are estimated. To evaluate the model performance, comparisons with the wealth capital stock values estimated in previous studies at the administrative prefecture-level and with the residential floor area statistics in the 2010-census at the administrative county/prefecture-level are conducted. The practicability of the modeled results in seismic risk assessment is also checked by estimating the seismic loss of residential buildings in Sichuan Province combined with the intensity map of the 2008 Wenchuan Ms8.0 earthquake and an empirical loss function developed from historical seismic damage information in China. Our estimated seismic loss range is close to that derived from field investigation reports. Limitations of this paper and future improvement directions are discussed. More importantly, the whole modeling process of this paper is fully reproducible, and all the modeled results are publicly accessible. Given that the building stock in China is changing rapidly, the results can be conveniently updated when new datasets are available.

A new complex world is emerging where a natural hazards event in a certain location, can have significant impacts on a different location either interlinked via economic sectors, infrastructure systems or other social relationships. In the past this was often not able to be quantified, but with increased reporting we are able to define these interactions better than previously.For a single location, multiple hazards can also occur in tandem, or one after another causing impacts or as a standalone. However, standalone events currently take on a whole new complexity with coronavirus protocols.Within the course of the EU project NARSIS (New Approach to Reactor Safety ImprovementS), sites of decommissioned nuclear power plants (NPPs) were investigated for external hazards combinations using a multi-hazard approach which took into account the joint probabilities including operational times and the effects of subsequent events. Here, different external hazards were applied such as tornadoes, lightning, earthquakes, floods and volcanic eruptions in tandem calibrated on historical events.In this work, we build a pan-European database using the backbone of CATDAT to define multi-hazard events of relevance with overlapping hazard and loss effects including events in 2020 and 2021 with significant effects due to coronavirus in combination with another hazard. We focus on the 1980-2021 time period within this database, although many older events have also been collected.In the year 2020, numerous events including the Croatian and Greece/Turkey earthquakes, medicanes, bushfires and many flood and storm events showed the complexity of combining multi-hazard protocols concurrently.The database will be extended within the MYRIAD-EU project in order to inform a multi-risk, multi-sector, systemic approach to risk management. Using empirical examples of socio-economic effects is one key step to understand the overlaps, and important within the calibration process of any multi-risk model.

Power plants are essential for modern life and blackouts are a frequent observation during natural disasters. Thus, assessing the specific hazards for power plant facilities is a crucial component of community risk management. However, multi-hazard assessments are rare and risk studies only rely on independent perils.For the European power plant sites, a multi-hazard assessment has been taken out considering earthquakes, flood, tornados and lightning. Each peril is considered independently. For each power plant location, return period curves for the relevant impact metrics like ground motion or wind speed have been compiled based on a variety of hazard model inputs. Those curves have been combined to provide threshold exceedance curves for any multi-hazard combination.The results have been facilitated within a software developed for the H2020 EURATOM NARSIS project (New Approach to Reactor Safety ImprovementS) to allow users to define relevant thresholds for different power plant system components like offsite power generators or the connecting road network. In addition, it allows to explore the site-specific hazard combinations. The tool is based on the Electron development framework.This study provides a general overview on the multi-hazard situation of Europe’s primary power producers and highlights sites where multi-hazard combinations may lead to infrastructure disruption. The results come with an easy-to-use tool to quickly assess the relevant metrics. It is hoped that these findings can help to increase the overall resilience of the European power network.

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

Seismic risk is typically quantified probabilistically for a single asset or evaluated through regional loss assessment for selected earthquake events. Ideally, a recurrence relationship for a loss quantity, economic loss or casualty, can be obtained for risk-informed decision-making. This can be achieved by a fully stochastic approach, for which a large amount of input information is required, whilst there is usually a lack of transparency that might hinder repeatability of the outputs. Hence, the objective of this paper is to introduce a simple and unambiguous procedure for developing parametric societal risk function based on rigorous loss modelling of response-specific probabilistic scenarios. This is then illustrated for the Greater Melbourne Region with fatality as the loss quantity. The proposed semi-probabilistic procedure can be extended to other loss quantities, as well as evaluating societal risk of other natural hazards or multiple hazards.

Transportation networks daily provide accessibility and crucial services to societies. However, they must also maintain an acceptable level of service to critical infrastructures in the case of disruptions, especially during natural disasters. We have developed a method for assessing the resilience of transportation network topology when exposed to environmental hazards. This approach integrates graph theory with stress testing methodology and involves five basic steps: (1) establishment of a scenario set that covers a range of seismic damage potential in the network, (2) assessment of resilience using various graph-based metrics, (3) topology-based simulations, (4) evaluation of changes in graph-based metrics, and (5) examination of resilience in terms of spatial distribution of critical nodes and the entire network topology. Our case study was from the city of Kathmandu in Nepal, where the earthquake on April 25, 2015, followed by a major aftershock on May 12, 2015, led to numerous casualties and caused significant damage. Therefore, it is a good example for demonstrating and validating the developed methodology. The results presented here indicate that the proposed approach is quite efficient and accurate in assisting stakeholders when evaluating the resilience of transportation networks based on their topology.

We estimate damage and loss to the residential building stock from tephra fallout for a re-eruption of the Laacher See Volcano in Germany with similar volcanological features as compared to the 10900BCE eruption (VEI = 6) but current population and wind conditions. This eruption was the largest eruption north of the Alps since the Late Quaternary. It generated several fallout fans with proximal deposits of several meters in height. The main cities that would be affected today are Cologne, Bonn, Koblenz and Frankfurt with a total population of at least 2.2 million people. We derive possible wind fields from an analysis of 44years of radiosonde observations provided by the Deutsche Wetterdienst (DWD). As they vary significantly with season, the loss numbers and patterns reflect this dependency. We use the HAZMAP software to calculate the spatial distribution of tephra. HAZMAP simulates the tephra distribution using a 2D advection-diffusion-sedimentation model. The tephra load as a hazard parameter is used to quantify roof and building damage. As the physical parameter for damage due to snow loads is comparable, we utilise the available knowledge on snow load damage to buildings and derive vulnerability curves that are representative within a geo-cell of 500 × 500m. Available information on the replacement values in each geo-cell are derived and loss estimation is undertaken. Depending on the wind conditions, we calculate a range of 18 to 27 billion Euros for the various scenarios. These absolute numbers translate to Mean Damage Ratios (MDR, ratio of absolute loss to Capital Stock in the affected area) of about 4%. This is very close to the MDR of the 1991 VEI 6 Pinatubo eruption in the Philippines.

Earthquake clustering is an essential part of almost any statistical analysis of spatial and temporal properties of seismic activity. The nature of earthquake clusters and subsequent declustering of earthquake catalogues plays a crucial role in determining the magnitude-dependent earthquake return period and its respective spatial variation for probabilistic seismic hazard assessment. This study introduces the Smart Cluster Method (SCM), a new methodology to identify earthquake clusters, which uses an adaptive point process for spatio-temporal cluster identification. It utilises the magnitude-dependent spatio-temporal earthquake density to adjust the search properties, subsequently analyses the identified clusters to determine directional variation and adjusts its search space with respect to directional properties. In the case of rapid subsequent ruptures like the 1992 Landers sequence or the 2010–2011 Darfield-Christchurch sequence, a reclassification procedure is applied to disassemble subsequent ruptures using near-field searches, nearest neighbour classification and temporal splitting. The method is capable of identifying and classifying earthquake clusters in space and time. It has been tested and validated using earthquake data from California and New Zealand. A total of more than 1500 clusters have been found in both regions since 1980 with M m i n = 2.0. Utilising the knowledge of cluster classification, the method has been adjusted to provide an earthquake declustering algorithm, which has been compared to existing methods. Its performance is comparable to established methodologies. The analysis of earthquake clustering statistics lead to various new and updated correlation functions, e.g. for ratios between mainshock and strongest aftershock and general aftershock activity metrics.

Previous seismic damage reports have shown that the damage and collapse of buildings is the leading cause of fatality and property loss, especially in developing countries. To better serve the risk analysis targeted at near-real-time post-earthquake mitigation and pre-earthquake preparedness and resources allocation, this study develops a fully reproducible grid-level residential building stock model for mainland China, by disaggregating urbanity level census data of each province into 1 km × 1 km scale and using population density profile as the proxy. To evaluate the model performance, the modelled residential building stock value is compared with the net capital stock value in Wu et al. (2014) using perpetual inventory method at provincial level. The modelled stock values in these two studies are in good agreement for all the 31 provinces in mainland China. Furthermore, district level comparison of the residential floor area developed in this study with records from statistical yearbook of Shanghai is also conducted. It turns out that the floor area developed in this study is compatible with floor area recorded in the yearbook of Shanghai. To further validate the applicability of the modelled results in seismic risk assessment, an estimation of the scenario loss to modelled residential buildings is performed, by assuming the recurrence of 2008 Wenchuan M8.0 earthquake. The overall estimated loss approximates the loss value derived from damage reports based on field investigation quite well. Both results indicate the reliability of the residential building stock model developed in this study. The limitations of this study are discussed and directions for future work are recommended.

Volcanic eruption sequences are often very long in length, and can cause significant downtimes and damage to infrastructure. Over the course of the H2020 EURATOM NARSIS project (New Approach to Reactor Safety ImprovementS), a review of volcanic sources for Europe was undertaken including historical impacts, source parameters and potential events to impact nuclear facilities either directly or operationally.The development of a volcano database of Eruption Source Parameters in order to estimate the tephra dispersal and its risk for the surrounding population and infrastructure is an important component for volcanic risk modelling.Each eruption is unique with different Eruption Source Parameters (ESPs), depending on the volcano and its surrounding area. The aim of the project is to create a global volcano database including the ESPs. With the help of this database it is possible to generate a risk map of tephra dispersal for future volcanic eruptions. This map can be used to estimate the potential risk of tephra fall for the surrounding population and infrastructure (development of isopahcs).The ESPs includes the plume height, the duration of the eruption, the volume, the mass and the grain-size distribution of the erupted material. Using local wind data it is possible to model an eruption and its range with open-source software packages, like Fall3D. A review of such open-source software packages has been undertaken. To get the ESPs of a volcano, which represent its typical eruptions, the eruption history of the volcano needs to be known. This is done using databases like the Smithsonian GVP, VOGRIPA and LaMEVE, as well as other reports and scientific articles.The intended result is a volcano database containing 1547 volcanoes. The ESPs for each volcano will be given in ranges to be able to determine the minimal and maximal effects of an eruption. However, data of previous eruptions will not in all cases be able to be found for every volcano. For these volcanoes, assumptions based on the behaviour of similar volcanoes need to be made. This will then be combined with the socioeconomic impacts of historic eruptions as have been collected as part of the CATDAT Damaging Volcanic Eruptions Database, as well as a reanalysis of historical eruptions for ashfall.

The evaluation of the seismic fragility of buildings is one key task of earthquake safety and loss assessment. Many research reports and papers have been published over the past four decades that deal with the vulnerability of buildings to ground motion caused by earthquakes in China. We first scrutinized 69 papers and theses studying building damage for earthquakes occurred in densely populated areas. They represent observations where macro-seismic intensities have been determined according to the Chinese Official Seismic Intensity Scale. From these many studies we derived the median fragility functions (dependent on intensity) for four damage limit states of two most widely distributed building types: masonry and reinforced concrete. We also inspected 18 publications that provide analytical fragility functions (dependent on PGA) for the same damage classes and building categories. Thus, a solid fragility database based on both intensity and PGA is established for seismic prone areas in mainland China. A comprehensive view of the problems posed by the evaluation of fragility for different building types is given. Necessary comparison with international projects with similar focus is conducted. Based on the newly collected fragility database, we propose a new approach in deriving intensity-PGA relation by using fragility as the bridge and reasonable intensity-PGA relations are developed. This novel approach may shed light on new thought in decreasing the scatter in traditional intensity-PGA relation development, i.e., by further classifying observed macro-seismic intensities and instrumental ground motions based on difference in building seismic resistance capability.

On 22 January 2013 an earthquake with local magnitude ML 4.1 occurred in the central part of the Gulf of Suez. Six months later on 1 June 2013 another earthquake with local magnitude ML 5.1 took place at the same epicenter and different depths. These two perceptible events were recorded and localized by the Egyptian National Seismological Network (ENSN) and additional networks in the region. The purpose of this study is to determine focal mechanisms and source parameters of both earthquakes to analyze their tectonic relation. We determine the focal mechanisms by applying moment tensor inversion and first motion analysis of P- and S-waves. Both sources reveal oblique focal mechanisms with normal faulting and strike-slip components on differently oriented faults. The source mechanism of the larger event on 1 June in combination with the location of aftershock sequence indicates a left-lateral slip on N-S striking fault structure in 21 km depth that is in conformity with the NE-SW extensional Shmin (orientation of minimum horizontal compressional stress) and the local fault pattern. On the other hand, the smaller earthquake on 22 January with a shallower hypocenter in 16 km depth seems to have happened on a NE-SW striking fault plane sub-parallel to Shmin. Thus, here an energy release on a transfer fault connecting dominant rift-parallel structures might have resulted in a stress transfer, triggering the later ML 5.1 earthquake. Following Brune’s model and using displacement spectra, we calculate the dynamic source parameters for the two events. The estimated source parameters for the 22 January 2013 and 1 June 2013 earthquakes are fault length (470 and 830 m), stress drop (1.40 and 2.13 MPa), and seismic moment (5.47E+21 and 6.30E+22 dyn cm) corresponding to moment magnitudes of MW 3.8 and 4.6, respectively.

Structural engineers design buildings according to the earthquake action (demand) specified in code of practice, whilst the rationale behind such requirement is commonly untold. In fact, even if a structure is designed strictly in accordance to the best standard and practice in the world, there is still a (small) chance of failure or collapse in an extreme earthquake event, due to the uncertainties in material properties and actual ground motions characteristics. This is the residual risk, which is unavoidable, and should be taken as a governing parameter for determining the performance goals of seismic design. This study attempts to establish the required (target) collapse risk limits for designing different types of ordinary buildings based on a well-accepted tolerable level of mortality risk and estimates of fatality rates in buildings. The proposed limits are compared with the target risk of collapse stipulated in the 2012 edition of the International Building Code (IBC). The risk-based approach presented in this paper should also be applicable for setting performance objectives for structural design of buildings and infrastructure against other natural, human-caused and technological hazards.

We focused on validation of applicability of semi-empirical technique (spectral models and stochastic simulation) for the estimation of ground-motion characteristics in the northeastern region (NER) of India. In the present study, it is assumed that the point source approximation in far field is valid. The one-dimensional stochastic point source seismological model of Boore (1983) (Boore, DM. 1983. Stochastic simulation of high frequency ground motions based on seismological models of the radiated spectra. Bulletin of Seismological Society of America, 73, 1865–1894.) is used for modelling the acceleration time histories. Total ground-motion records of 30 earthquakes of magnitudes lying between MW 4.2 and 6.2 in NER India from March 2008 to April 2013 are used for this study. We considered peak ground acceleration (PGA) and pseudospectral acceleration (response spectrum amplitudes) with 5% damping ratio at three fundamental natural periods, namely: 0.3, 1.0, and 3.0 s. The spectral models, which work well for PGA, overestimate the pseudospectral acceleration. It seems that there is a strong influence of local site amplification and crustal attenuation (kappa), which control spectral amplitudes at different frequencies. The results would allow analysing regional peculiarities of ground-motion excitation and propagation and updating seismic hazard assessment, both the probabilistic and deterministic approaches.

The evaluation of the seismic fragility of buildings is one key task of earthquake safety and loss assessment. Many research reports and papers have been published over the past four decades that deal with the vulnerability of buildings to ground motion caused by earthquakes in China. We scrutinize 69 papers with studies of building damage for magnitude ≥ 4.7 events occurred in densely populated areas starting with the 1975 M7.5 Haicheng earthquake. They represent observations where macroseismic intensities have been determined according to the Chinese Official Seismic Intensity Scale. From these many studies we derive the most representative fragility functions (dependent on intensity) for 4 damage limit states of two most widely distributed building types: masonry and reinforced concrete. We also inspect 18 papers that provide analytical fragility curves (dependent on PGA) for the same damage classes and building categories. Finally, we check the consistency of fragilities as functions of intensity and PGA and derive corresponding relationships between macroseismic intensity and PGA. The intensity-PGA relationship developed in this study is fully compatible with results of previous research.

A theoretical frame of seismicity evolution due to stress changes in a medium is the rate- and state-dependent theory of frictional fault motion. The evolution is expressed in the form of a differential equation, which can be used for normal stress changes on faults caused by fluid pressure changes resulting from injection. If the pressures rate is high enough the seismic activity becomes proportional to the local pressure rate in accordance with the Critical Pessure Theory. Examples including constant pressure injection, shut-in and variable injection rates lead to results comparable to the Critical Pressure Theory.

Knowledge of the present-day crustal in-situ stress field is a key for the understanding of geodynamic processes such as global plate tectonics and earthquakes. It is also essential for the management of geo-reservoirs and underground storage sites for energy and waste. Since 1986, the World Stress Map (WSM) project has systematically compiled the orientation of maximum horizontal stress (S-Hmax). For the 30th anniversary of the project, the WSM database has been updated significantly with 42,870 data records which is double the amount of data in comparison to the database release in 2008. The update focuses on areas with previously sparse data coverage to resolve the stress pattern on different spatial scales. In this paper, we present details of the new WSM database release 2016 and an analysis of global and regional stress pattern. With the higher data density, we can now resolve stress pattern heterogeneities from plate-wide to local scales. In particular, we show two examples of 40 degrees-60 degrees S-Hmax rotations within 70 km. These rotations can be used as proxies to better understand the relative importance of plate boundary forces that control the long wave-length pattern in comparison to regional and local controls of the crustal stress state. In the new WSM project phase IV that started in 2017, we will continue to further refine the information on the S-Hmax orientation and the stress regime. However, we will also focus on the compilation of stress magnitude data as this information is essential for the calibration of geomechanical-numerical models. This enables us to derive a 3-D continuous description of the stress tensor from point-wise and incomplete stress tensor information provided with the WSM database. Such forward models are required for safety aspects of anthropogenic activities in the underground and for a better understanding of tectonic processes such as the earthquake cycle.

There is no simple method to calculate indirect losses. However, key components of indirect losses can be examined rapidly using an indicator framework. The framework introduced in this study allows relative ranking of specific portfolios (e.g., selection of firms), countries, or provinces. A selection of suitable indicators has been undertaken for the indirect economic loss potential on both a country (level 1) and for Japan at a province (level 2) comparison. This was done using the available Japan data set that comprises much of the specific literature on indirect losses. The result is a map that denominates relative indirect losses. This map could be used in combination with, for example, a traditional downtime model to provide differentiation between various businesses that are dependent on business from others. In addition, it provides a framework for the application of various concepts such as the building characteristics associated with downtime. The index is relative rather than absolute and to calculate tangible losses, business income information needs to be compared with business interruption downtime. The current index provides a first-order model for obtaining a ranking of the vulnerability of countries and provinces to indirect loss potential informed by the detailed studies of indirect losses of past historic events and typical inputs used in other more complex methodologies.

Insurance catastrophe modeling of natural risks requires three key components of information: (1) a catalog of all possible events that can occur within the time period considered, (2) an exposure database consisting of the built parameters of insured structures or the population exposed to the hazard (usually in the form of a portfolio), and (3) the susceptibility of the structures or population at risk to the hazard. This chapter focuses on each of these components herewith highlighting recent trends in losses. To do this, CATDAT (Daniell et al., 2011) data are used for describing both economic as well as insured markets. Results indicate that normalized losses are in general decreasing most likely due to increasing hazard mitigation and decreasing vulnerability. Statistics as to the last 100 years (from 1900 to 2015) suggest that flood has been dominating historical losses. The statistical results have implications for future events. This article also considers how historic data are used in forming vulnerability functions along with how data might best be adjusted for changes in values, among others. Concepts such as replacement cost, hazard metrics, vulnerability functions, and spatial disaggregation of the average annual loss are then highlighted using an Australian earthquake model created by the authors.

Rural transportation networks are highly susceptible to geohazards such as earthquakes and landslides. Indirect losses can be severe because the breakdown of a transportation network aggravates rescue, supply, and other recovery activities. The operations and logistics of rural networks that are under seismic risks must be managed using the limited resources specifically in developing countries. We propose a methodology to evaluate road recovery strategies for restoring connectivity after blockages due to earthquakes and earthquake-triggered landslides. This paper gives insight into the recovery process, which can be used by decision-makers for enhancing resilience and supplying immediate relief to rural areas. The proposed framework has four steps: 1) identification of strategies for increasing recovery performance, 2) determination of graph-based metrics to represent network connectivity, 3) applying topology-based and Monte Carlo simulations to each strategy, and 4) analysis of recovery times to compare these resilience-enhancement strategies. The methodology was tested using a case study from Sindhupalchok District, Nepal, a region that was severely affected by the Gorkha earthquake in 2015. The closed road segments and recovery times were determined through field surveys with locals and governmental authorities, and by investigating the intensity of earthquake-triggered landslides. Our results showed that the proposed approach provides information about the recovery behavior of road networks and simplifies the evaluation process. It is robust enough to extend and assess decision-makers’ preferences for improving resilience., International Journal of Disaster Risk Reduction, 31, ISSN:2212-4209

The results of classical probabilistic seismic hazard analysis (PSHA) contain no information about simultaneous ground motions at different sites during a particular earthquake. Seismic risk analysis for distributed critical structures requires estimates of the level of earthquake shaking that are likely to occur concurrently at multiple locations: whether the vulnerable elements of a lifeline system are likely to be simultaneously affected by shaking of sufficient strength to disable them and whether the shaking at any one of critical points may be sufficient to cause failure of the whole system. While the analysis of lifeline performance requires multiple-location estimations, the sparsely located elements of a network or critical facilities are designed on the basis of point-wise PSHA. In this paper we study specific features of multiple-location PSHA, as compared with the classical point-wise PSHA, using Monte Carlo simulations. We analyze the level of ground motion (PGA) that will be exceeded at any site inside a particular area or at several sites simultaneously with reference annual probability. The analysis has been performed for regions of Western and South-Western Germany, Northern and Eastern Taiwan, which represent different levels of seismicity (low, moderate and high, respectively). The relationship between the multiple-location and point-wise estimations are analyzed and quantified. Results of the study may be used to decide whether it may be possible to utilize the procedure of point-wise PSHA in particular cases of multiple-location PSHA, i.e. for assessment of maximum level of ground motion among several sites, or for estimation a reasonable lower safety level when considering simultaneous exceedances.

Consideration of within-earthquake ground-motion correlation is essential for the estimation of seismic hazards, damage, and loss for spatially distributed systems. In many seismically active regions, the strong motion data of real engineering significance are completely unavailable or very scarce. The absence of necessary data does not allow developing regional empirical correlation models, and the models obtained for other regions should be used with correspondent sensitivity analysis. The level of within-earthquake correlation may vary in broad range; therefore, development of correspondent criteria for selection from available models is important. In this paper, we analyzed the performance of a system of critical elements of electric power network (substations) depending on variations in within-earthquake correlation. The performance is described as probability of different levels of non-functionality, i.e., percentage of area suffering power outage, and probability of expected number of customers without power. We have shown that the proper choice of the within-earthquake correlation model is critical in comprehensive estimations of functionality of substations in electrical power system. Skipping the ground-motion variability and within-earthquake correlation may lead to unreliable results. Relevance of geology-based within-earthquake correlation models has been demonstrated, and a scheme, which allows reducing uncertainty in the choice of realistic correlation, has been proposed.

The number of people affected by natural hazards is growing, as many regions of the world become subject to multiple hazards. Although volume of geophysical, sociological and economic knowledge is increasing, so are the losses from natural catastrophes. The slow transfer from theory to practice might lay in the difficulties of the communication process from science to policy-making, including perceptions by stakeholders from disaster mitigation practice regarding the usability of developed tools. As scientific evidence shows, decision-makers are faced with the challenge of not only mitigating against single hazards and risks, but also multiple risks, which must include the consideration of their interrelations. As the multi-hazard and risk concept is a relatively young area of natural risk governance, there are only a few multi-risk models and the experience of practitioners as to how to use these models is limited. To our knowledge, scientific literature on stakeholders' perceptions of multi-risk models is lacking. In this article we identify perceptions of two decision-making tools, which involve multi-hazard and multi-risk. The first one is a generic, multi-risk framework based on the sequential Monte Carlo method to allow for a straightforward and flexible implementation of hazard interactions, which may occur in a complex system. The second is a decision-making tool that integrates direct input from stakeholders by attributing weights to different components and constructing risks ratings. Based on the feedback from stakeholders, we found that interest in multi-risk assessment is high but that its application remains hampered by the complexity of processes involved.

Probabilistic seismic hazard assessment (PSHA) is widely used in earthquake engineering practice and seismic risk management. However, the results of classical point-wise PSHA contain no information about simultaneous ground motions during one earthquake at different sites located within a defined area. Such multiple-site estimations are very useful for assessment of damage and corresponding losses in densely populated areas and for analysis of lifeline performance. Recently Wenzel and Sokolov (2018) introduced parameter that describes probability that specified ground motion level (e.g. design ground motion) will be exceeded at least once in at least fraction of the reference area during specified period of time. The parameter was called as Fraction of Areal Exceedance (FAE). The estimations of FAE may be used both for the risk management decisions and for selection of appropriate design ground motion. This article describes the sensitivity analysis of FAE that includes consideration of various input characteristics that may influence on the results.

We analyzed the within-earthquake correlation (peak ground acceleration PGA and velocity PGV) in Japan by taking into account local geological conditions. The database includes more than 23,700 records (K-NET and the KiK-net networks) from 84 events (M 4.2–7.4) occurring in 1999–2011. The correlation structure was investigated for residuals obtained using two recently developed ground-motion models for Japan. We have shown that the level of within-earthquake correlation may vary significantly depending on site classes, general geological conditions and earthquake magnitude. The results of the analysis are in general agreement with the findings obtained recently for Taiwan (Sokolov et al. in Bull Earthq Eng 10(5):1401–1429, 2012. doi: 10.1007/s10518-012-9368-5 ). The high level of ground-motion correlation reflects the presence of a non-random component in the residuals that may be caused by the joint influence of surface soil and thick sediments, and this influence depends on the earthquake magnitude. Therefore, a single generalized model of within-earthquake correlation across geologically heterogeneous regions may not be adequate. The application of empirical correction factors, which may be a function of earthquake magnitude, source-to-site distance, site class, and average shear-wave velocity for a given station, allows for effective reduction in the level of within-earthquake correlation.

Ground motion intensity measures such as the peak ground acceleration (PGA) and the pseudo-spectral acceleration (PSA) at two sites due to the same seismic event are correlated. The spatial correlation needs to be considered when modeling ground-motion fields for seismic loss assessments, since it can have a significant influence on the statistical moments and probability distribution of aggregated seismic loss of a building portfolio. Empirical models of spatial correlation of ground motion intensity measures exist only for a few seismic regions in the world such as Japan, Taiwan and California, since for this purpose a dense observation network of earthquake ground motion is required. The Istanbul Earthquake Rapid Response and Early Warning System (IERREWS) provides one such dense array with station spacing of typically 2 km in the urban area of Istanbul. Based on the records of eight small to moderate ( M w 3.5– M w 5.1) events, which occurred since 2003 in the Marmara region, we establish a model of intra-event spatial correlation for PGA and PSA up to the natural period of 1.0 s. The results indicate that the correlation coefficients of PGA and short-period PSA decay rapidly with increasing interstation distance, resulting in correlation lengths of approximately 3–4 km, while correlation lengths at longer natural periods (above 0.5 s) exceed 6 km. Finally, we implement the correlation model in a Monte Carlo simulation to evaluate economic loss in Istanbul's district Zeytinburnu due to a M w 7.2 scenario earthquake.

We analysed the within-earthquake correlation of ground motion using the strong-motion records accumulated by the TSMIP (Taiwan Strong Motion Instrumentation Program) network in Taiwan during 1993–2009. Two ground-motion prediction equations, which were recently developed for peak ground acceleration (PGA) in the region and based on moment and local magnitude and hypocentral distance, were used for the calculation and analysis of ground-motion residuals. We also used the database containing shear-wave velocity data averaged for the top 30 m of the soil column (Vs30) for the TSMIP stations. We showed that the within-earthquake correlation may vary significantly depending on site classes, gross geological features of the area, and magnitude of earthquakes, records of which dominate the analysed dataset. On the one hand, there is a prominent correspondence between the within-earthquake correlation of PGA residuals and spatial correlation of Vs30 values, which was estimated for particular geological structures (e.g., sedimentary filled basins and large plain areas). On the other hand, the high level of ground-motion correlation (or significant non-random component of residuals) may be caused by the joint influence of soft surface soil and thick sediments and by the path or azimuthal effects. The point-source approximation of extended fault and neglected hanging- and foot-wall effects may also result in non-random residuals. The application of empirical correction factors, which consider the magnitude of earthquakes, source-to-site distance and Vs30 value for given stations, allows for the effective reduction in the level of within-earthquake correlation, as well as the within-earthquake standard deviation. The results of the analysis may be used in practical estimates of seismic hazard, damage and loss for spatially distributed structures (portfolios, lifelines) in Taiwan, as well in other regions with similar geological characteristics.

Induced seismicity in geothermal projects is observed to continue after shut-in of the fluid injection. Recent experiments show that the largest events tend to occur after the termination of injection. We use a probabilistic approach based on Omori’s law and the Gutenberg–Richter magnitude–frequency distribution to demonstrate that the probability of exceeding a certain maximum magnitude still increases after shut-in. This increase is governed by the exponent of Omori’s law q and the Gutenberg–Richter b value. For a reduced b value in the post-injection phase, the probability of occurrence directly after shut-in can be even higher than the corresponding probability for an ongoing injection. For the reference case of q = 2 and a 10% probability at shut-in time t S to exceed a given maximum magnitude, we obtain an increase to 14.6% for t = 2t S at a constant Gutenberg–Richter b value after shut-in. A reduction of the b value by one quarter leads to a probability of 20.5%. If we consider a constant probability level of occurrence for an event larger than a given magnitude at shut-in time, this maximum magnitude increases by 0.12 units for t = 2t S (0.26 units for a reduced b value). For the Soultz-sous-Forets (France) injection experiment in 2000, recent studies reveal q = 9.5 and a b value reduction by 14%. A magnitude 2.3 event 9 h after shut-in falls in the phase with a probability higher than for the continued injection. The probability of exceeding the magnitude of this post-injection event is determined to 97.1%.

The global CATDAT damaging earthquakes and secondary effects (tsunami, fire, landslides, liquefaction and fault rupture) database was developed to validate, remove discrepancies, and expand greatly upon existing global databases; and to better understand the trends in vulnerability, exposure, and possible future impacts of such historic earthquakes. Lack of consistency and errors in other earthquake loss databases frequently cited and used in analyses was a major shortcoming in the view of the authors which needed to be improved upon. Over 17 000 sources of information have been utilised, primarily in the last few years, to present data from over 12 200 damaging earthquakes historically, with over 7000 earthquakes since 1900 examined and validated before insertion into the database. Each validated earthquake includes seismological information, building damage, ranges of social losses to account for varying sources (deaths, injuries, homeless, and affected), and economic losses (direct, indirect, aid, and insured). Globally, a slightly increasing trend in economic damage due to earthquakes is not consistent with the greatly increasing exposure. The 1923 Great Kanto ($214 billion USD damage; 2011 HNDECI-adjusted dollars) compared to the 2011 Tohoku (>$300 billion USD at time of writing), 2008 Sichuan and 1995 Kobe earthquakes show the increasing concern for economic loss in urban areas as the trend should be expected to increase. Many economic and social loss values not reported in existing databases have been collected. Historical GDP (Gross Domestic Product), exchange rate, wage information, population, HDI (Human Development Index), and insurance information have been collected globally to form comparisons. This catalogue is the largest known cross-checked global historic damaging earthquake database and should have far-reaching consequences for earthquake loss estimation, socio-economic analysis, and the global reinsurance field.

Recent studies have shown that the proper treatment of ground-motion variability and, particularly, the correlation of ground motion are essential for the estimation of the seismic hazard, damage and loss for distributed portfolios. In this work we compared the effects of variations in the between-earthquake correlation and in the site-to-site correlation on probabilistic estimations of seismic damage and loss for the extended objects (hypothetical portfolio) and critical elements (e.g. bridges) of a network. Taiwan Island has been chosen as a test case for this study because of relatively high seismicity and previous experience in earthquake hazard modelling. The hazard and loss estimations were performed using Monte Carlo approach on the basis of stochastic catalogues and random ground-motion fields. We showed that the influence of correlation on parameters of seismic hazard, characteristics of loss distribution and the probability of damage depend, on one hand, on level of hazard and probability level of interest (return period) and, on the other hand, the relative influence of each type of correlation is not equal.