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.

The 1923 Kanto earthquake (M_J=7.9) has great significance for seismic hazard assessments of the Tokyo metropolitan area, because it caused extensive damage to the area. To deepen our understanding of the strong ground motion of the Kanto earthquake, this paper reviewed studies on its observed strong ground motion and found that 1) seismic intensity VI on the Japanese scale (IX or X on the M. M. scale) was widely distributed in an area of approximately 8,000 km², which is equivalent of that of the 2011 M9 Tohoku earthquake, 2) strong effects of soil amplification on ground motion were suggested by the correlation of the damage distribution with surface geology, 3) the restoration of the scaled-out seismogram indicated that the ground motion at the upland of Tokyo would be roughly 50 cm/s for maximum velocity and 50 cm for maximum displacement, and 4) the ground motion in the epicentral area is unclear, but would be roughly twice or more as strong as that at Tokyo.

The 1923 Great Kanto Earthquake is one of the earthquakes that have occurred multiple times in the past as part of the Sagami Trough earthquakes. These earthquakes, which occurred at the plate boundary, occurred in 1495 (Meio Earthquake), 1703 (Genroku Earthquake), and again in 1923, causing significant damage to various areas in Kanto, including Tokyo and Yokohama, and it came to be known as the Great Kanto Earthquake. The Sagami Trough earthquakes have consistently brought strong tsunami disasters to various areas in Kanto, extending from the Sagami Bay coast to the Boso Peninsula, and residents along the coast were highly aware of the risk of tsunamis occurring after major earthquakes. Although a tsunami occurred in the Great Kanto Earthquake of 1923, it is believed to have had a wave height approximately half that of the tsunami in the Genroku Earthquake. However, this tsunami destroyed the livelihoods of villages and caused significant damage. In this study, we aim to reexamine historical records related to the tsunami in the Great Kanto Earthquake and objectively evaluate the actual situation of this tsunami disaster.

Charles A. Beard, a prominent American scholar, and Shinpei Goto, Home Minister and former mayor of Tokyo, forged a close friendship in 1922–23 based on their mutual interest in the so-called scientific management approach to planning, urban management, and public administration. In New York City, Beard directed the programs of the fifteen-year-old Bureau of Municipal Research and Training School for Public Service, which fostered reform and practical improvements in public management through applied studies. Goto invited Beard to Japan to lecture, study the problems of Tokyo, and help develop the Tokyo Institute for Municipal Research which Goto established and chaired. Beard’s influence was already cemented by June 1923 when his report—later published as “The Administration and Politics of Tokyo”—was presented to Goto. Their relationship would deepen and expand after September 1, 1923 when the Great Kanto Earthquake occurred and Goto again reached out to Beard in what was likely the first telegram out of the country after the disaster, asking Beard to return to help. Beard returned for six weeks, during which the general outlines of reconstruction were developed by the Reconstruction Bureau headed by Goto. Much has been written about those six weeks, about the failure of Goto to win support for his grandest plans, and about the role Beard may have played in helping to shape both Goto’s thinking and the actual, scaled down plans that were approved and built. On the occasion of the 100th anniversary of the Great Kanto Earthquake, it is worth revisiting the literature and looking more closely at Beard’s contributions.

When the Kanto earthquake struck on Saturday the 1st of September 1923 at a few minutes to noon, the foreign residents from western countries in the harbour city of Yokohama reached 2,500, and a similar presence was in Tokyo, which as the capital hosted the officers of embassies, consulates, and trade companies. These foreign residents left impressive records of the earthquake occurrence, as well as the fire that started immediately after. To add a different viewpoint to the overall understanding of this earthquake disaster, we concentrated on the considerable quantity of documents now stored at the National Archives (Kew Gardens, UK) and at the Affaires étrangères-Archives diplomatiques (La Courneuve, France). These documents were produced by British and French diplomats and naval commanders as well as foreign residents of different nationalities who were in Yokohama and Tokyo at the time of the earthquake. The immediacy of the descriptions they contain and the details they supply about the earthquake, the fire, and the rescue and relief actions bring us back to the shaking and shocking moments experienced by the people living in Yokohama and Tokyo one hundred years ago.

The year 2023 marks the 100th commemoration of the disastrous Kanto Earthquake in Japan, which shattered the urban fabric of Tokyo and other southern prefectures. In the years following 1923, much research into disaster risk reduction (especially fire prevention) was undertaken. This study evaluated research trends and the impact of the earthquake on the city using metropolitan population data. The following is reported: (1) This study summarized English and Japanese academic papers and reports on the Great Kanto Earthquake that have been published over the last 100 years. (2) The area of fire spread and number of damaged buildings in Tokyo due to the Great Kanto Earthquake were overwhelmingly larger than those in other areas. (3) The difference in the relative amount of damage caused by natural disasters with more than 1,000 death toll to the annual national budget in Japan became clear. (4) The Great Kanto Earthquake was the only natural disaster that caused a net worth of damage exceeding the Japanese national budget by 3.8 times. (5) The expansion of the Tokyo metropolitan area over the 100 years since the Great Kanto Earthquake was visually clarified based on demographics. (6) Today, many people live densely on soft ground, with an amplification factor of 1.8 or higher, which is 23.0% of the total population.

The Tokyo Electric Light Company, Inc., the largest electric power company in pre-war Japan, took an active merger policy and started accounting manipulations to maintain high dividends in the 1920’s. It, however, suffered extensive damage in 1923 when the Great Kanto Earthquake occurred and covered the damage by devising the appraisal profits of its fixed capital, which, though frequent in those days, constituted arbitrary accounting manipulations with no objective criteria. The Great Kanto Earthquake induced moral hazards to its management resulting in normalization of the accounting manipulations in the best interest of high dividends. Such accounting manipulations triggered the intervention of Mitsui Bank, Ltd. in its management, and partly contributed to the government control of electric power. As disasters are likely to show the inherent problems within companies, any temporary solution would instead result in more severe consequences.

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.

During the Great Kanto Earthquake, fire ravaged the city beyond its firefighting capabilities at that time. This also applies to contemporary society. Today, as Japan is facing a declining birthrate and an aging population, resources for public assistance-led disaster prevention measures are also dwindling. We have experienced the limitations of public-assistance-led disaster reduction measures for numerous disasters; for example, the Great East Japan Earthquake. Following the background, in recent years, the concept of “phase-free” has attracted the consideration as a means of preparing for disasters that exceed the scope of our corresponding range. The purpose of this study was to formulate a process of disseminating disaster prevention education that is effective in terms of both children’s learning ability and disaster preparedness through an analysis of a case study on the application of the phase-free concept (PFC) to school disaster prevention education. In PFC, disaster prevention and mitigation considerations are integrated into daily life. In Japan, several companies and local governments have begun to implement this concept. This study is based on a case study of phase-free efforts in school disaster prevention education in Naruto City, Japan. Through qualitative surveys conducted from the stakeholders, this research is focused to answer the question “Why was the PFC able to spread in actual schools throughout Naruto City?” These findings indicate that the PFC helps explain Naruto City’s proactive approach to disaster management as well as explains actors’ dynamic participation in phase-free activities. Furthermore, the research findings suggest that the term “phase-free” has become a marker of the perception of quality (Merkmal in German) in disaster prevention that promotes collaboration among diverse stakeholders.

On the occasion of centenary anniversary of the Great Kanto Earthquake and commencement of radio broadcasting in Japan, this study reiterates the paramount importance of medium-wave (MW) AM broadcasting in safeguarding public safety and security. Utilizing the electromagnetic principles of MW, the author has earlier developed hoop-shaped radio (HOOPRA), which is a battery-free sustainable radio receiver. This study aims to determine the maximum achievable reception distance with HOOPRA for broadcasts from public stations, such as Nihon Hoso Kyokai (NHK) JOFG (927 kHz, 5 kW) in Fukui; and NHK JOAK (594 kHz, 300 kW) and JOAB (693 kHz, 500 kW) in the Kanto region. The significance of the findings in this study is that approximately 38 million individuals in the Kanto region, residing within an 80-km radius of JOAK or JOAB, can access broadcasts using only the energy of radio waves with HOOPRA. Additionally, ∼0.4 million people in Fukui, within a 15-km radius of JOFG, can potentially be recipients of the broadcast. Given that most transmitting stations operate at 5-kW power nationwide, HOOPRA can be effectively utilized within a 15-km radius of each station. Moreover, these outcomes validate the efficacy of HOOPRA as a radio receiver and provide valuable insights into the global potential applicability of MW AM radios. Furthermore, the current investigation underscores the need to reevaluate the significance of terrestrial MW broadcasting as a vital source of emergency information, especially in the event of anticipated natural disasters, such as the predicted Nankai Trough Earthquake.

On September 1, 2023, 100 years after the Great Kanto Earthquake, the Hiroshima City Torrential Rain Disaster Museum will open in the Yagi district of Asaminami Ward, the area most severely affected by the landslide that struck Hiroshima City on August 20, 2014. Given the unpredictable nature of risk events, sustainability in risk communication, one of the countermeasures, is important. This article discusses sustainable risk communication methods, focusing on two methods of learning from past disasters: “facilities” and “storytelling by survivors.”