The range of liquefaction caused by the 2011 Great East Japan Earthquake was very wide, from the Tohoku region to the Kanto region. Post-earthquake studies have shown that the reasons for this wide range were the long duration of shaking and continuous aftershocks. In many residential areas, roads and lifelines were damaged at the same time as wooden houses, making it difficult to live in these areas. Therefore, measures such as lowering the groundwater level were taken to prevent an entire city area from liquefying due to future earthquakes. In the hills, many areas where valleys had been filled with soil to make them residential areas suffered severe damage, such as slides of slopes and subsidence of the fill. Since many similar filled residential areas have been constructed in Japan, their stability during future earthquakes is currently being checked.

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Infrastructures such as water and gas supply systems, electric power and communication systems, highways and railways are important utilities and transportation systems for our lives. Firstly, the earthquake damage to infrastructures after the 2011 Great East Japan Earthquake is focused on and summarized with the casualty and the building damage. The earthquakes of which damage is described here are the 2011 Off the Pacific Coast of Tohoku earthquake, the 2016 Kumamoto earthquake, the 2018 Osaka-Fu Hokubu earthquake and the 2018 Hokkaido Eastern Iburi earthquake. In Japan, since both inter- and intra-plate earthquakes can take place at anytime and anywhere, we need to consider countermeasures for disaster reduction from every aspect. For the Nankai Trough Mega Earthquake, lessons learnt from the Great East Japan Earthquake become very useful materials to mitigate the future earthquake disaster. Based on these resources and recent advanced knowledge obtained, the issues to be considered are picked up and the problems to be solved are discussed.

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By using Twitter, which has many users and is superior in quickness and simplicity, it is possible to collect many reactions from users even immediately after the eruption. The purpose of this study is to clarify the needs and issues of the general public for volcanic ash (ash fall), by analyzing Twitter data posted at the time of the 2014 Mt. Ontake eruption. Results of the analysis reveal a high degree of attention to the initial coverage, needs for quantitative ash fall prediction and ash fall observation results, and countermeasures for ash fall, and lack of users’ knowledge and information on eruptions. By providing appropriate information to the media, or disseminating the information from volcano experts using Twitter, we can contribute to meeting the above needs and solving problems.

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Because future occurrence of flood damage and sediment disasters is feared to result from the influences of climate change, voluntary work by professionals who assist survivors during and after wide-scale disasters is extremely important. Voluntary work by professionals’ activities and tasks to be resolved for effective future support actions must be clarified. Therefore, we specifically examined the Liaison Meeting of Professionals Including House Inspectors, Real-Estate Appraisers and the like for Hiroshima Prefecture Reconstruction Support. They administered survivor assistance in cooperation with the disaster volunteer center and a regional mutual support center in Hiroshima prefecture, where severe damage by heavy rains occurred in July 2018. Study results obtained from a questionnaire survey quantitatively clarified actual conditions of survivor assistance and elucidated points to be resolved before future activities.

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The tornado occurred at 8:22 am on September 22, 2019 near Hamamachi in Nobeoka City, Miyazaki Prefecture, during typhoon No.17 (Tapah), which was progressing in a northeast direction on the west coast of Kyushu in the East China Sea. It passed through the north side of the JR Minami-Nobeoka station and ran through Asahi-Kasei’s factory groups in the Tsunetomi district and Nakashimamachi. Furthermore, the tornado then went across the Gokase-River and passed through Showamachi, on the north side of the JR Nobeoka station, Nakagawaramachi, crossed the Houri-River in Yamatsukimachi and ran through the rice paddy area in Natsutamachi, on the west side of Nobeoka Commercial High School in the Sakuragaoka district at 8:40 am, and then went north and disappeared on the hillside. According to the field investigation, the migration length of the tornado was 7.3 km and the maximum damaged width recorded in Showamachi was300m. From film taken by a camera at Nobeoka Office of Rivers and the National Highway, the speed of the tornado was estimated at approximately 55 km/h. The building damage was evaluated as JEF2, based on the guideline of the Japanese Enhanced Fujita scale.

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To explore the activities required of female and student fire corps volunteers in preparation for future large-scale storm and flood disasters, we conducted a questionnaire survey of volunteer fire corps in 248 cities, towns, and villages across Japan to which the Disaster Relief Act was applied due to the storms and flood disasters that occurred between 2015 and 2019. The questionnaire asked about problems encountered during activities, and excellent activities in which female and student members were engaged, and so on. Based on the results of the questionnaire, we proposed that the common activities required of female and student fire corps volunteers are “evacuation shelter support”, “evacuation public relations”, and “information gathering and sharing”. In addition to these activities, it would be desirable for student members to engage in “removal work”and “record keeping”.

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