Earthquake Risk Research Articles

A Comprehensive Numerical Model for Reservoir-Induced Earthquake Risk Assessment.

The assessment of seismic risk and the prevention of earthquake occurrences during reservoir operation present significant challenges in terms of accurate determination. This study aims to address this issue by developing a numerical model. The primary objective is to estimate the vulnerability of different fault types to reservoir impoundment. This model integrates essential parameters such as fault dip and the relative orientation between the reservoir and potential earthquakes, and it is structured within a risk framework using polar coordinates. Through comprehensive computations, we evaluate the alterations in elastic stress and fluid pore pressure resulting from water impoundment. This is achieved by employing a fully coupled two-dimensional poroelastic approach. Furthermore, our model incorporates relevant seismic data to enhance its accuracy. The findings of our study underscore that the critical factor lies in the fault's precise positioning with respect to the reservoir. The risk associated with a fault is contingent upon both its location and its orientation, emphasizing the importance of these factors in determining hazardous zones.

Simulation‐based characterization of the variability of earthquake risk to buildings in the near‐field

AbstractRecent advancements in high performance computing platforms and computational workflow for regional‐scale simulations are enabling unprecedented modeling of fault‐to‐structure earthquake processes. Regional simulations resolving ground motions at frequencies relevant to engineered systems are becoming computationally viable and provide a new capability to improve understanding of the geographical distribution and intensity of risk to buildings and critical infrastructure. As computational capabilities advance, it is essential to move beyond illustrative single rupture realizations for scenario earthquake events towards the development of a full suite of rupture realizations that appropriately characterize the range of risk to building systems. The work described in this article investigates the application of a suite of fault rupture realizations with the objective of assessing near‐fault, site‐specific seismic demand variability for building structures. A representative high‐performance regional‐scale computational model is utilized to execute ground motion and building response simulations based on 18 kinematic rupture realizations of an M7 strike‐slip scenario earthquake. The fault rupture models for the scenario earthquake are created by systematically perturbing the hypocenter location and stochastically generating rupture parameters (slip, rise time, rake angle) to represent a breadth of ground motion intensities resulting from the spatial and temporal variabilities of an earthquake rupture process. The resulting seismic demand variability for three‐story (short period) and forty‐story (long period) steel moment‐resisting frame buildings is characterized in terms of the median and distribution of peak inter‐story drift ratio for a range of near‐fault sites. The full suite of 18 fault rupture realizations and approximately 280,000 nonlinear dynamic building simulations indicate that the three‐story building undergoes higher median seismic demand and significantly greater variability of demand at a given site than the forty‐story building, which has important implications for the level of certainty in predicting building performance during an earthquake. The simulations performed provide deeper insight into the relationship between fault rupture parameterization and building response, which is essential information for developing a representative suite of rupture realizations for specific earthquake scenarios.

Dynamic analysis of historıcal masonry arch bridges

There are many historical bridges belonging to various civilizations in our country. Historical bridges also help us understand the sociological, economic and cultural structures of civilizations that lived between the past and the present. Historical bridges have been deformed due to natural events and human factors and some of them have been destroyed. It is extremely important to know the behavior of these bridges against earthquakes, since a large part of our country is located in a region with high earthquake risk. For this reason, the dynamic behavior of structures is examined with numerical and experimental studies, and earthquake analyzes are made using earthquake acceleration records obtained from past earthquakes or artificial earthquakes. In this direction, it is aimed to strengthen the weak aspects of the structures. For this reason, it is necessary to evaluate the behavior of historical masonry bridges that have survived to the present day in order to carry out restoration and protection. In this article, the historical Sultan Hamid I-II and III bridges in the Askale district of Erzurum province are discussed as a numerical application. These bridges were modeled in three dimensions using the SAP2000 finite element program. First of all, static analyzes of the bridges under their own weight were made. Then, the dynamic properties of the bridges were determined by making modal analyzes. After the dynamic properties of the bridges were determined, dynamic analyzes were made in the time period.

Social vulnerability and geographic access barriers to earthquake early warning education in museums and other free choice learning environments

Given the earthquake risk on the West Coast of the United States, individuals and communities require a basic understanding of ShakeAlert earthquake early warning technology, which may provide crucial seconds of warning. Free choice learning environments (FCLEs), such as museums, public libraries, and national parks, are uniquely positioned to expand the reach of earthquake early warning through educational initiatives and resources. Earthquake education in these spaces creates awareness of earthquake hazards and risk in areas where people live or visit and may also increase engagement in preparedness behavior as they are trusted sources of information in their communities. However, population demographics within the ShakeAlert states has yet to be examined; audience segmentation theories require a better understanding of the demographics of the people the system seeks to serve. Here we build upon previous typology research that examined over 150 earthquake displays around the United States and found that most did not include information about earthquake preparedness or associated protective actions. This new research shifts to a hierarchical clustering analysis that identifies seven main population groups within the ShakeAlert states. We also find that the cost of admission and the geographic distance away from FCLEs, including the potential cost and time of transportation, may lead to an urban-rural divide in visitor access. Using audience segmentation theories as related to earthquakes, we can understand critical barriers to FCLEs and opportunities for ShakeAlert education. As earthquake early warning systems expand internationally, thoughtful and equitable education initiatives are beneficial to reach critical audiences.

Seismic and Tsunami Risk Analysis for Installing Resilient Power Systems Based on Isolated Microgrids on Buildings: The Case of Puerto Ayora in Santa Cruz Island, Galapagos

Due to their geographical condition and worldwide environmental protection policies, the Galapagos Islands must opt for implementing clean energy infrastructure considering natural hazard effects that can directly affect the resilience of community residents. Santa Cruz Island is part of this archipelago, with rich biodiversity in flora and unique fauna. This study proposes identifying earthquake and tsunami risk assessment components on the island, such as the infrastructure vulnerability of Puerto Ayora, the central city of Santa Cruz Island. The FEMA P-154 and FEMA P-646 methodologies are used to classify buildings for technically installing microgrids based on photovoltaic generation systems. For this purpose, maps and data from state entities are used in combination with catalogs from development and land use planning, Software for Geoprocesses and virtual tours, and cadastral information provided by the Decentralized Autonomous Government (GAD) of Santa Cruz to develop techniques that offer a risk index to identify buildings that could sustain seismic and tsunamic loads. The study exposes alarming results that would prevent the installation of photovoltaic generation systems on the buildings’ roofs. Consequently, a more detailed field study is recommended to contrast the reported analysis to implement mitigation strategies accordingly. Finally, geoprocesseced maps are presented, in addition to general installing recommendations for the photovoltaic system’s infrastructure.

Localization Strategy of Building Fire Following Earthquake Risk Assessment Method

Localization Strategy of Building Fire Following Earthquake Risk Assessment Method

Earthquake Consideration in Architectural Design: Guidelines for Architects

Architectural planners must give due consideration to seismic events as they present substantial hazards to both critical infrastructure and human well-being. This research investigates the fundamental concepts and methodologies employed by architects to enhance seismic resilience in buildings and ensure the safety of occupants. It emphasizes the importance of seismic hazard assessment, design standards, structural systems, and cutting-edge technology in reducing earthquake-related dangers. A mixed method has been adopted: surveying the literature, applying inductive reasoning, and conducting a case study. This research highlights the value of interdisciplinary cooperation between structural engineers, geotechnical experts, and architects to design resilient built environments that can survive the pressures unleashed by seismic occurrences. The findings demonstrated that architectural design solutions and approaches might significantly impact earthquake risk reduction techniques in seismic and non-seismic locations. In the cases taken, different techniques—in some cases multiple techniques—had been applied based on the buildings’ geographical locations, sizes, and shapes. Finally, we prepared a checklist for these strategies, including mass distribution, openings, rooftop structures, and other considerations to be applied by architects to make the solutions easier.

Quantitative Earthquake Loss Estimates the New Frontier

Abstract Since 2003, an early focus has emerged on estimating earthquake fatalities, injuries, and financial losses. This new inquiry is not yet practiced by a majority of researchers, even though one might argue it is the most important question in seismology today. No sensitive structures like reservoir dams and nuclear power plants could be built without a detailed seismic hazard analysis specifically focused on the site. On the other hand, cities near large active faults do not have their building codes determined by rigorous and specific seismic hazard and risk analyses. This contrast is startling. It seems that where mostly money is at stake, it is mandatory to consider deterministic seismic hazard analyses for construction, whereas where mostly lives are at stake, it is not. I advocate that it should be mandatory for every major city near active faults to have the seismic hazard and risk estimated so as to put an adequate local building code and other safety measures in place. To this end, a standard procedure should be defined to assess local earthquake risk in populated areas exposed to earthquake hazards. In numerous countries, the population numbers in villages, as well as the locations and sizes of schools and hospitals, are not known, and some governments refuse to distribute this information, in spite of the fact that it would be for humanitarian purposes. Because the Open Street Map and Open Building Map begin to cover the globe, this missing information, essential for first responders in natural disasters, will become available and will contribute to preparing populations at risk to reduce the impact of unavoidable future earthquakes.

Global building exposure model for earthquake risk assessment

The global building exposure model is a mosaic of local and regional models with information regarding the residential, commercial, and industrial building stock at the smallest available administrative division of each country and includes details about the number of buildings, number of occupants, vulnerability characteristics, average built-up area, and average replacement cost. We aimed for a bottom-up approach at the global scale, using national statistics, socio-economic data, and local datasets. This model allows the identification of the most common types of construction worldwide, regions with large fractions of informal construction, and areas prone to earthquakes with a high concentration of population and building stock. The mosaic of exposure models presented herein can be used for the assessment of probabilistic seismic risk and earthquake scenarios. Information at the global, regional, and national levels is available through a public repository ( https://github.com/gem/global_exposure_model ), which will be used to maintain, update and improve the models.

A site amplification model for Switzerland based on site-condition indicators and incorporating local response as measured at seismic stations

AbstractThe spatial estimation of the soil response is one of the key ingredients for the modelling of earthquake risk. We present a ground motion amplification model for Switzerland, developed as part of a national-scale earthquake risk model. The amplification model is based on local estimates of soil response derived for about 240 instrumented sites in Switzerland using regional seismicity data by means of empirical spectral modelling techniques. These local measures are then correlated to continuous layers of topographic and geological soil condition indicators (multi-scale topographic slopes, a lithological classification of the soil, a national geological model of bedrock depth) and finally mapped at the national scale resorting to regression kriging as geostatistical interpolation technique. The obtained model includes amplification maps for PGV (peak ground velocity), PSA (pseudo-spectral acceleration) at periods of 1.0, 0.6 and 0.3 s; the modelled amplification represents the linear soil response, relative to a reference rock profile with VS30 (time-averaged shear-wave velocity in the uppermost 30 m of soil column) = 1105 m/s. Each of these amplification maps is accompanied by two layers quantifying its site-to-site and single-site, within event variabilities, respectively (epistemic and aleatory uncertainties). The PGV, PSA(1.0 s) and PSA(0.3 s) maps are additionally translated to macroseismic intensity aggravation layers. The national-scale amplification model is validated by comparing it with empirical measurements of soil response at stations not included in the calibration dataset, with existing city-scale amplification models and with macroseismic intensity observations from historical earthquakes. The model is also included in the Swiss ShakeMap workflow.

Assessing network-based earthquake early warning systems in low-seismicity areas

Earthquake early warning (EEW) technology, designed to alert the public of earthquake risks after initial P-wave detection but before the onset of strong tremors, has developed rapidly. Methodologies from various fields are combined in EEW systems to estimate earthquake locations, magnitudes, and expected intensities based on the initial P-wave data. These systems operate automatically because prompt responses are required. However, as no common evaluation framework for EEW system verification exists, potentially divergent evaluations from reviewers or countries could ensue. Moreover, evaluating EEW systems is more complicated when the target area does not experience frequent earthquakes. We aimed to establish a guidance review process for low-seismicity areas to ensure reliable and stable integrated EEW system operation. We incorporated management aspects through actual system operator surveillance and designed an EEW assessment process based on feedback from our surveys. Using this approach, we created a comprehensive and well-informed evaluation process that considers the diverse perspectives of experts involved in EEWs. Our proposed assessment method allows for a uniform and consistent evaluation process, regardless of changes in the methods or technologies used by EEW systems. The method aims to guide EEW system assessments in low-seismicity areas.

Earthquake early warning in Central America: The societal perspective

Central America has an elevated seismic risk, resulting from the vulnerability of the building stock and steady population growth. Earthquake Early Warning (EEW) aims to provide warning in advance of imminent shaking, allowing recipients to take action and reduce casualties during damaging motions. The Swiss Seismological Service (SED) has been collaborating with local seismic agencies to develop national EEW systems across Central America, which can potentially benefit nearly 47 million inhabitants. We conducted a public survey to comprehend the desire for EEW, the preferences for EEW attributes, and the current behaviour of people during earthquakes and the driving factors behind it. We recruited participants from Nicaragua (N = 513), Costa Rica (N = 1350), Guatemala (N = 559), and El Salvador (N = 491). In all four countries, participants consider it necessary to have an EEW system, are tolerant of false alerts, and are likely to react promptly to alerts. The desirable alert threshold is for low felt intensities, ranging between MMI III to IV. We found that a significant number of respondents already take protective action when earthquakes strike, and appropriate reactions are expected to increase when EEW is available. Our survey is unique in providing insights into the social dimension of EEW systems in low-income regions with high earthquake risk and where no operational EEW system yet exists.

Analysis of Disaster Risk on Expressways for Foreign Tourists to Japan Using Rental Cars: Study Using Central Nippon Expressway Pass

The travel patterns of foreign visitors to Japan are changing from group travel, which was the mainstream to date, to individual travel, and there has been an increase in the number of cars rented by visitors as a means of transportation. The use of rental cars improves access to rural areas and is being promoted as a means of transportation. However, if a natural disaster occurs while driving a rental car, then the individual may face difficulties owing to a lack of local support. Therefore, the traffic volume on the roads used by foreign visitors to Japan during certain periods needs to be estimated in advance as well as the natural disaster risks that exist on those roads. In this study, we utilized CEP data managed by the Central Nippon Expressway Company in Japan to identify the risk of disaster for foreign visitors to Japan who use expressways with rental cars. The CEP data has usage records of foreign visitors to Japan who used rental cars on expressways in the Chubu region of Japan during the period from 1 April 2018 to 31 March 2019. Using this data, we calculated the risk of earthquake and landslide disasters. Result of this analysis, it is clear that the risk of earthquake disasters is high on expressways in the Tokai region, and the risk of landslide disasters is high on expressways in mountainous areas.

Local government capacity for earthquake disaster risk reduction in Malaysia: Case studies in Bentong and Selayang areas

This paper investigates the status of earthquake disaster risk reduction (DRR) capacity of local governments (LG) in Malaysia, and the factors that influence the LGs’ capacity to reduce earthquake risk. Currently, there is a lack of understanding and systematic study of the capacity of LG to address earthquake DRR even though the LGs in Malaysia are at the forefront of the national agenda to carry out DRR actions at the local level. A qualitative methodology was utilised based on a comparative case study design involving two cases of LG in Malaysia with the risks in dealing with earthquakes i.e. Bentong Municipal Council and Selayang Municipal Council. The study employed semi-structured interviews and documentation analysis as its data collection methods. To ensure a systematic data collection, a capacity assessment framework (CAF) had been developed based on key capacity categories identified according to the powers and responsibilities of the LG as outlined by UNDRR, and components of UNDP capacity building. The findings of this study suggested that inadequacy of LG in Malaysia to address earthquake DRR measures are mainly due to several capacity issues: insufficient financial backing, lack of knowledge and required expertise, lack of specific unit to tackle DRR issues, and low utilisation of existing resources such as inter-agency networking and regulations. The findings highlighted the need to empower the LG with improved capacities and governance structures. This paper concludes with several recommendations on how the LG can address key capacity gaps identified in this study.

Geospatial mapping of surgical systems for earthquake emergency planning in Guerrero, Mexico: an ecological study

Accessibility to surgical services can impact earthquake preparedness and response. We aimed to estimate the population with timely access to surgical care in Guerrero, a Mexican state with high tectonic activity, and identify populations at risk in the event of an earthquake. We conducted an ecological study using open government data. We extracted data from Guerrero municipalities regarding their earthquake risk, social vulnerability, social inequality, marginalisation, and resilience indices. The latest combines municipalities' resistance to unexpected events and capacity to maintain optimal functionality without immediate federal or international support. Geographical coordinates of active public and private surgical facilities in Guerrero were combined with ancillary spatial data on roads and municipalities' population density to estimate population coverage within 30-min and 1-h driving time to surgical facilities in Redivis. We built an ordered beta regression model for each driving time estimate. We identified 25 public and 16 private facilities capable of providing surgical care in Guerrero. The population with access to facilities with surgical capacity within 30min and 1-h driving times were 48.4% and 69.1%, respectively. We found that municipalities with very high levels of earthquake risk, social vulnerability, social inequality, and marginalisation, and very low levels of resilience had decreased coverage. In the multivariable analysis, the resilience index was statistically significant only for the 30-min model, with an effect size of0.524 (95% CI 0.082, 1.089). Access to surgical care remains unequally distributed in Guerrero municipalities at the highest risk for earthquakes. Municipalities' resilience was the most significant predictor of higher surgical care coverage in 30-min driving time. Our study provides insights on how surgical system strengthening can enhance earthquake emergency disaster planning. No funding.

The black swans of nuclear repositories – an overview of external events with a potentially serious impact on the long-term operation and safety

Abstract. For Germany, the time until completion and final closure of a repository is estimated to be up to 150 years. So far, it has been implicitly assumed that external political, economic, and infrastructural functions that are necessary for the construction, operation, and closure of such facilities will be fully in place throughout the entire operating period. These include, for example, power supply, presence of well-trained staff, and effective oversight. Event sequences initiated by natural disasters or human-made crises may lead to unintentional long-lasting disruptions of these external safety functions. They are currently only partly considered in safety assessments. To make repository concepts robust against such scenarios, a forward-looking risk analysis is required that creates the basis for a holistic comparative risk assessment of different repository concepts. It provides a starting point for the development of additional resilient structures, management processes, and safety functions. A risk analysis includes an assessment of event-specific vulnerabilities as well as potential consequences of unintended external hazards for various disposal concepts. The first step of this process would be a hazard analysis – a summary and evaluation of external event sequences that have the potential to compromise essential safety elements of a repository within the predicted operation period. These can be divided into political–economic crises and event sequences following transnational natural disasters. A look at the political development of the past 150 years shows that even if only the present territory of Germany is considered, there have been profound disruptions, such as three wars, several major economic depressions, revolutionary government changes, and attempted military coups. This summary shows that political and economic stability as well as a continuous orderly operation cannot be taken for granted. Historic as well as present experiences from the country where the repository is planned as well as the neighbouring regions should be considered when assessing the potential consequences of such events. Local natural disasters are already taken into account in site selection, e.g. risk of flooding, volcanism, or earthquakes. Less attention is typically given to the indirect effects of transnational disastrous events. These include climatic extremes (e.g. droughts), cosmic and geological disasters (e.g. geomagnetic storms) and their climatic consequences (e.g. volcanic winter), and pandemics. Such natural disasters may cause economic depressions and subsequently contribute to political turmoil (e.g. the drought of 1788 as one of the causes of the French Revolution in 1789). At the stage of concept design, additional safety elements, measures, and processes should be included that help to manage situations of external stress and to avoid irreversible processes that challenge the safety architecture of the repository.

An Enhanced Earthquake Risk Analysis using H3 Spatial Indexing

Risk assessment is the first step in disaster risk reduction and crucial for types of disasters with potentially significant impacts, such as earthquakes. Besides the direct impact of very devastating shocks, earthquakes can also trigger cascading events that are no less damaging such as landslides, liquefaction, and tsunamis. This study aims to apply the H3 spatial indexing system to improve earthquake risk assessment using Sorong City as a case study, and compare the result of H3-based risk assessment with the normative risk assessment in Indonesia as defined by relevant Perka BNPB (Badan Nasional Penanggulangan Bencana/National Disaster Management Authority) 2/2012. H3 is an open-source geospatial indexing system developed by Uber, which utilizes a hierarchical hexagonal grid for indexing, calculations, and visualization. The hexagonal cells in the grid have equidistant neighbors and possess the property of expanding neighboring rings, approximating circles and optimizing space filling. The H3 spatial index finds extensive applications in earthquake hazard, vulnerability, capacity, and risk assessment systems. The value of each parameter is entered into each hexagon so that in the end each hexagon has its risk index value. The study shows that the use of H3 in earthquake risk assessment can provide a more detailed level of analysis and indirectly does not depend on regional administrative boundaries. Technically, this advantage provides a more efficient calculation method and is also easier to modify partially both spatially and in terms of the parameters used. Based on the performance evaluation results on the spatial join aspect, H3 provides much faster performance compared to traditional indexing systems. Hence, the H3 spatial index will be very useful to meet the need for an earthquake risk assessment on a larger scale with a higher level of resolution.

Repositioning Earthquake Risk Reduction: Implications to Global Risk Landscape

Concepts and approaches of earthquake risk reduction have evolved over time. The Great Kanto Earthquake of 1923 has paved the pathway of this long journey. 1995 the Great Hanshin-Awaji Earthquake has taught the importance of self help and mutual help in terms of community participation, volunteer activities, and role of civil society. In the first international decade of disaster risk reduction, two landmark earthquake risk reduction projects, namely risk assessment tools for diagnosis of urban areas against seismic disaster (RADIUS) and global earthquake safety initiative (GESI) have made significant impacts to scenraio-based risk assessment, and raising awareness of local governments mainly in developing countries to undertake decisive actions. The Kutch Earthquake of 2001 of India has prompted the need of owner driven reconstruction (ODR), which is considered inclusive as well as sustainable in long run. While the pre-disaster preventive measures for earthquake risks are challenging, the new complex global risk landscape poses additional challenges which need to be addressed to reposition earthquake risk reduction. It is argued that addressing systemic risks, active involvement of private sectors, role of new and emerging technologies, understanding priorities of new generation, and role of new entrepreneurship (in the form of Science-preneurship) are some of the future pathways to address the complexity of earthquake risk reduction.

Earthquake Risk Potential Caused by Active Faults in Sumatra (Case Study: Earthquakes in the Land of West Sumatra Province and its vicinity)

The land of West Sumatra province is one of prone area stricken by the destructive earthquakes. Based on historical records, the land of West Sumatra province has a high seismic risk related to the earthquake events along active faults, such as the Sianok, Barumun, Sumani, Siulak and Angkola faults. Some destructive earthquakes occurred in these faults and caused fatalities in West Sumatra area and its vicinity, e.g., the earthquakes near Bukit Tinggi district in 1926, 1977, 2007 (doublet earthquakes-Tabel 1) and 2022. A previous study shows that the Sumani, Siulak, Sianok, Barumun and Angkola faults has a potential magnitude 7.1-7.7, a geodetic slip-rate of 6-14 mm/y respectively and these move generally strike slip. Using these magnitude scenarios to make the earthquakes impact modelled, we find the maximum intensity is about of VII-VIII MMI scale, the Peak Ground Acceleration (PGA) is about of 42-64 % g, and Peak Ground Velocity (PGV) is about of 30-50 cm/s for the assumption of 5-15 km hypocentral depth. Also with using the scaling law relation of earthquake parameters and magnitude scenarios the earthquake return period can be calculated by a kinematic model with the source mechanism was modelled as a strike slip faults. Estimation of the earthquake return period with magnitude (Mw) scenarios about 7.1-7.7 for these active faults is about of 114 until 612 years for strike slip model respectively. This method can be developed to make identically assessment for others active fault in Sumatra region and the result can be used as one of a consideration to support of planning of the long term landscape in the prone of earthquakes area.

Special Issue on the 100th Anniversary of the Great Kanto Earthquake

On September 1, 1923, the Great Kanto Earthquake struck the Tokyo metropolitan area of Japan. It was an extremely powerful earthquake that caused a great fire. The death toll reached approximately 105,000, and the economic loss is estimated to have exceeded 30% of the Japanese gross national product at that time. For September 2023, the Journal of Disaster Research (JDR) has planned a special issue to commemorate 100 years since the Great Kanto Earthquake. While previous special issues by the JDR have focused on specific disasters, this special issue will focus on the lessons and findings from the catastrophe and will cover even the progress of disaster research since then. We received fourteen important and thought-provoking manuscripts not only on scientific and engineering aspects but also on social and cultural aspects, including comparisons with other disasters, historical views, reconstruction issues, and future perspectives. These fourteen articles can be categorized into the three groups described below. The first four articles are the English translations of articles that originally appeared in “Koho Bosai,” the bimonthly journal on natural disaster reduction that is complied and published by the Disaster Management Section, Cabinet Office, Government of Japan. The JDR believes that these four articles provide a concise English description of various aspects of the Great Kanto Earthquake disasters. Dr. Takemura summarizes the seismic features of the 1923 Kanto Earthquake. Dr. Sekizawa summarizes the large scale urban fires that it caused. Dr. Suzuki describes various aspects of the emergency responses. Dr. Murosaki details the recovery project in Tokyo. Those articles discussed various lessons learned from the 1923 Kanto Earthquake and emphasized the importance of transferring the lessons toward future disaster mitigation. The next six papers were originally works studying various aspects of the Great Kanto Earthquake disasters. Dr. Midorikawa reviews the strong ground motion of the 1923 Kanto Earthquake. Dr. Kaneko evaluates the resulting tsunami. Mr. Mammen sheds new light on the relationship between Charles A. Beard and Goto Shinpei in terms of the recovery. Dr. Albini studies the voices of foreign residents who left impressive disaster processes at that time. Dr. Murao reviews the urbanization of Tokyo after the Kanto Earthquake. Dr. Shima studies the response of the Tokyo Electric Light Company, Inc. to the 1923 Great Kanto Earthquake. The last four papers are works on various aspects of disaster risk reduction, but all of these works were inspired by the 1923 Great Kanto Earthquake in one way or another. Dr. Shaw provides a framework for repositioning earthquake risk reduction. Dr. Shimbo explores the Phase Free Concept. Dr. Shoji focuses on the possibility of Medium-Wave AM Radio Broadcasting. Dr. Yamaguchi studies the Risk Communication Method. The Editorial Board of the JDR thanks all of these contributors and hopes that these articles serve as great sources for further research in disaster risk reduction.