Japan has one of the highest levels of seismicity in the world. In the last few decades, Japan has been the site of many destructive earthquakes, such as the 1995 Kobe earthquake, 2003 Tokachi-oki earthquake, 2004 Chuetsu earthquake, 2007 Chuetsu-oki earthquake, and 2016 Kumamoto earthquake/Tottori-chubu earthquakes.
Furthermore, we need to take disaster mitigation countermeasures in preparation for the next Nankai Trough megathrust earthquake, Tokyo earthquake, etc. Disaster countermeasures against these earthquakes will be of vital importance to Japanese society in the future.
As a specific example, if and when the next Nankai Trough megathrust earthquake strikes, it will cause widespread and compound disasters on the island of Shikoku and in southwestern Japan in general. The prefectures of Kagawa, Tokushima, Kochi, and Ehime are all on the island of Shikoku, yet the damages that a future Nankai Trough megathrust earthquake will cause are predicted to be quite different in each prefecture. Therefore, in preparing disaster mitigation strategies for the coming Nankai Trough megathrust earthquake, these four prefectures and the distinguished universities involved in disaster mitigation research and education in them must be united in collaboration while making the best use of the individual characteristics of the prefectures and universities.
Specifically, in terms of disaster mitigation preparations, universities on Shikoku have to develop and advance resilience science as it relates to upcoming disasters from a Nankai Trough megathrust earthquake, inland earthquakes, typhoons, floods, etc.
In this special issue, many significant research papers from the fields of engineering, geoscience, and the social sciences by researchers from distinguished universities on the island of Shikoku focus on resilience science. We must apply their findings to society, putting them into practice to mitigate potential damages from any future natural events.
The world falls victim to many natural disasters, including disasters from tsunamis, earthquakes, volcanic eruptions, tornados, hurricanes, floods, landslides, and droughts.
Above all, attention has been drawn to destructive tsunamis and earthquakes, such as the 2004 Sumatra earthquake and tsunami, the 2010 Chile earthquake, and the 2011 East Japan earthquake and tsunami.
My personal experience with disasters, tsunamis, and earthquakes has taught me that they can cause severe damage to buildings, the environment, and people in societies in coastal areas (Fig. 1).
Since the East Japan earthquake and tsunami in 2011, restoration and revival from the extensive damage caused by the natural disasters has not progressed rapidly in the coastal areas of East Japan.
There are many reasons for this, such as the lead times for restoration and recovery, reconstruction budgets, and the time spent generating consensus among the national government, local governments, and people living in the coastal areas on the restoration plans.
Furthermore, mental and economic restoration for each individual affected by the disaster in coastal areas and others is very far from returning to the normal state – the one before the disaster.
Therefore, advanced measures for disaster mitigation, restoration, and revival in coastal areas are indispensable in advance of the next destructive earthquake and tsunami.
In this paper, I will first present examples of tsunami and earthquake damage in Japan and the rest of the world, and countermeasures, resilience science, and resilience society.
Resilience is the capability to promptly recover from damage caused by a disturbance. In recent years, “resilience engineering” has been drawing attention as a new concept in the disaster prevention and crisis management field. Resilience engineering is a method for improving resilience through actions and responses on a case-by-case basis. It is based around social and technological systems, and includes both individuals and organizations. When a system encounters an unprecedented situation, this method involves avoiding the worst-case scenario based on “responding ability,” “monitoring ability,” “anticipating ability,” and “learning ability.” This paper introduces an application case for early recovery planning related to road networks damaged by an earthquake using the resilience engineering method. It also discusses the utility of the resilience engineering method and its future deployment for increasing disaster resilience.
To deal with large-scale disasters, it is necessary to maintain important community functions. One way to achieve this goal is through strategic collaboration with local organizations to ensure district continuity in the aftermath of disaster. It is therefore necessary for local organizations to form a consensus in order to draft measures for the reduction of disaster damage, enabling each organization to act strategically in a post-disaster situation. These measures taken together are called a district continuity plan (DCP).
In this paper, the concept of district continuity is defined as a BCP method. The utility of this method is clarified through two case studies. The Kagawa DCP focuses on a possible future Nankai Trough earthquake, and the Basin DCP against large-scale flooding is based on the DCP concept.
After the Nankai earthquake in 1946, the resultant flooding lasted for a long time, because seawater remained on land after the tsunami in Kochi city. Large-scale flooding occurred in Ishinomaki city immediately after the Great East Japan Earthquake in 2011. Long-term flooding may hamper disaster responses such as rescue and recovery activities. This paper studied the risks of long-term flooding after the Nankai earthquake in Tokushima city based on a paleographical survey and numerical analysis. The paleographical survey identified statements such as “seawater sometimes flowed onto the land at the full tide,” suggesting occurrences of long-term flooding after previous Nankai earthquakes. The numerical analysis separately calculated values inside and outside the levee.
The tsunami waveforms outside the analysis area obtained by tsunami numerical simulation was used as the boundary condition of the inland flow modeling, that is water was introduced inside the levee when the tsunami water level exceeded the upper end of the levee. The two layers of ground surface and the drain were defined to calculate the flow, including water exchange between the two layers, and the water was drained forcefully outside the levee using a drainage pump. The possibility of long-term flooding in the analysis area is suggested when a large-scale earthquake occurs in the Nankai trough.
Increase in number of disaster prevention experts in various fields of our society has led to greater expectations for their activities as local disaster prevention leaders. It may be of interest as well as necessary to understand what motivates people to become a disaster prevention expert. In this study, we first compare altruistic motivation levels of disaster prevention experts program attendees with those of general public for locality-based disaster mitigation plan, and then discuss appropriateness of such possibility. In addition, on the basis of the knowledge of social psychology, altruistic motivation and related awareness of both groups are also comparatively discussed.
For the purposes of disaster prevention and disaster mitigation against the upcoming Nankai Trough Earthquake, various efforts are being carried out. The undertaking is on the basis of lessons learned from the experience of the 2011 earthquake off the Pacific coast of Tohoku and other disasters. In the Kochi Prefecture, where serious damage is expected, significant effort is being directed towards preparing social infrastructure countermeasures for the earthquake and, particularly, the tsunami. This paper focuses on the efforts towards local resilience being made in the Kochi Prefecture and discusses new disaster-prevention countermeasures with respect to sea dikes, liquefaction, and tsunami fires.
We constructed a real-time tsunami prediction system using the Dense Oceanfloor Network System for Earthquakes and Tsunamis (DONET). This system predicts the arrival time of a tsunami, the maximum tsunami height, and the inundation area around coastal target points by extracting the proper fault models from 1,506 models based on the principle of tsunami amplification. Since DONET2, installed in the Nankai earthquake rupture zone, was constructed in 2016, it has been used in addition to DONET1 installed in the Tonankai earthquake rupture zone; we revised the system using both DONET1 and DONET2 to improve the accuracy of tsunami prediction. We introduced a few methods to improve the prediction accuracy. One is the selection of proper fault models from the entire set of models considering the estimated direction of the hypocenter using seismic and tsunami data. Another is the dynamic selection of the proper DONET observatories: only DONET observatories located between the prediction point and tsunami source are used for prediction. Last is preparation for the linked occurrence of double tsunamis with a time-lag. We describe the real-time tsunami prediction system using DONET and its implementation for the Shikoku area.
This paper describes earthquake and tsunami scenarios as basic information for preparing for the next Nankai megathrust earthquakes. Models to clarify the size of the Nankai megathrust earthquake and changes in occurrence intervals, simulations using such models, and simulations of crustal deformations and tsunamis based on the simulations were employed. This paper re-examines past earthquakes and tsunamis, the possibility of slightly larger earthquakes and tsunamis, their sizes, the necessity of countermeasures against subsidence caused by earthquakes in the Inland Sea, the possibility of the Nankai earthquake occurrence before the Tokai (Tonankai) earthquake, and the possibility of the triggering of the Nankai earthquake by the Hyuga-nada earthquake.
This study proposes experience-based training in evacuation due to earthquakes for school teachers. The purpose is for school teachers to develop their practical disaster response capabilities to save lives. Although disaster reduction education is important, conventional disaster reduction education in schools in Japan has been delivered in accordance with procedures from the education manual for disaster reduction. Conventional education materials may provide knowledge and skills in disaster reduction, but in order to take appropriate action as a disaster unfolds, it is important to develop practical capabilities by using the knowledge and skills acquired. In this study, we propose a method of training aimed at developing practical disaster response capabilities. We propose experience-based evacuation training to raise the response capabilities of school teachers. The proposed method employs a training simulator that reproduces disaster situations through a mixture of real and virtual space. An example of the training is provided to demonstrate its usefulness and that of the training simulator.
This study considered glacier and snow meltwater by using the degree–day method with ground-based air temperature and fractional glacier/snow cover to simulate discharge at Skardu, Partab Bridge (P. Bridge), and Tarbela Dam in the Upper Indus Basin during the monsoon season, from the middle of June to the end of September. The optimum parameter set was determined and validated in 2010 and 2012. The simulated discharge with glaciermelt and snowmelt could capture the variations of the observed discharge in terms of peak volume and timing, particularly in the early monsoon season. The Moderate Resolution Imaging Spectroradiometer (MODIS) daily and eight-day snow cover products were applied and recommended with proper settings for application. This study also investigated the simulations with snow packs instead of daily snow cover, which was found to approach the maximum magnitude of observed discharge even from the uppermost station, Skardu.
This study estimated the glacier and snow meltwater contribution at Skardu, Partab Bridge, and Tarbela as 43.2–65.2%, 22.0–29.3%, and 6.3–19.9% of average daily discharge during the monsoon season, respectively. In addition, this study evaluated the main source of simulation discrepancies and concluded that the methodology proposed in the study worked well with proper precipitation.
From previous experiences, it was suggested that stakeholders should collaborate in each phase of disaster risk reduction, in order to prevent and mitigate the impact of wide area natural disasters.
However, in several cases, the collaboration was not fruitful, owing to the diverse visions of both, private and public organizations’ operational continuity, resulting in conflicts occurring effortlessly among the organizations.
One of the solutions to overcome this challenge is applying the business continuity management (BCM) method, such as business impact analysis (BIA) and risk assessment, to the area. Japan International Cooperation Agency reported the “Area BCM” concept in 2013. This paper further investigates the concept of “Area BCM” and introduces the idea to decompose BIA factors for area and individual purposes, in order to build sustainable local economies.
Corporate social responsibility (CSR) is now considered to be one of the most important activities for companies as it greatly affects both companies and local communities. This study analyzes the effects of corporate social responsibility activities on the life recovery of employees. A questionnaire survey on the Great East Japan Earthquake Disaster in Iwaki City (Fukushima, Japan) was conducted. Iwaki City was among the areas most severely affected by the disaster. The effect of CSR activities on the life recovery of employees was analyzed by structural equation modeling. Life recovery largely depended on health and human relationships. CSR activities related to these two factors, such as work–life balance and local community activities, increased the life recovery of employees. Companies have large resources for improving local community resilience and local communities can recover from a disaster in a timely and effective manner when companies provide appropriate assistance. This study reveals how companies can contribute to the recovery of local communities through their CSR activities.