The state of so-called disaster consciousness has generally been seen as one of the typical determinants of evacuation behavior during floods. However, the preconception that a high level of disaster conscious- ness ought to lead to a high rate of evacuation, and that a low rate of evacuation is because of a low level of disaster consciousness, is overly simplistic. In this paper, a counterexample from Thailand is given in which a high level of disaster consciousness leads to a low rate of evacuation, and this is then contrasted with a case from Japan in which a high level of consciousness leads to a high rate of evacuation. Using a questionnaire survey, unified data were collected. The investigation found that the respondents in Thailand tended to remain in their own homes during a flood disaster because of their high disaster consciousness. Consequently, in such a region, disaster risk management education that aims to raise disaster consciousness should be implemented after social unrest is quelled.

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We proposed a forecast model that uses a neural network to predict what the winter road surface tem- perature will be after three hours in order to increase the efficiency of anti-icing programs. In order to establish the forecast model, learning models of the road surface temperature using three sets of input var- iables at a specific site were created. These learning models were then applied to other sites along an ex- pressway, and the correct classification of the road surface temperature was examined. The results of the present study revealed that the road surface temperature along an expressway can be predicted three hours in advance more than 76% of the time by applying a learning model to the time series variation of the road surface temperature and other variables, such as the hourly traffic volume and the effect of spreading anti- icing chemicals.

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The 2014 and 2015 eruptions of Kuchinoerabujima Volcano followed a ~15-year precursory activation of the hydrothermal system induced by a magma intrusion event. Continuous heat transfer from the degassing magma body heated the hydrothermal system and the increase of the fluid pressure in the hydrothermal system caused fracturing of the unstable edifice, inducing a phreatic explosion. The 2014 eruption occurred from two fissures that traced the eruption fissures formed in the 1931 eruption. The explosive eruption detonated the hydrothermally-altered materials and part of the intruding magma. The rise of fumarolic activities before the past two activities in 1931-35 and 1966-1980 also suggest activation of the hydrothermal system by magmatic intrusions prior to the eruption. The long-lasting precursory activities in Kuchinoerabujima suggest complex processes of the heat transfer from the magma to the hydrothermal system.

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In this study, airborne ash dispersal from the eruption of Kuchinoerabujima Volcano in Japan on 29 May 2015 is simulated using the volcanic ash tracking PUFF model. A major eruption occurred at 9:59 am local time (0:59 UTC), and the ash plume reached 9 km above the ground. According to MTSAT-2 satellite monitoring, the ash plume with a mushroom-shaped distribution drifted in the east-southeast direction. The observed ash fallout over Yakushima Island is in the order of 100 g/m2. Using this observational fact, we estimated that a particle in the numerical model represents 60 tons of ash mass. Based on this number, total emissions are estimated to be 600,000 tons for this event. The result suggests that the ash concentration in the air can also be estimated by this method. According to the aviation safety report, an ash density of 4 mg/m3 and above is considered as a danger zone for commercial airliners. The PUFF model simulation shows that the core region of the plume front at 9 km in height indicates 100 mg/m3 of airborne ash density even for the plume 250 km from the erupting volcano. The satellite images show the exact location of the ash plume. The PUFF model simulation can therefore estimate the airborne ash density over a much wider diffused area to identify the danger zone for aircraft.

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We observed long-period seismic waves excited by eruptions in 2014 and 2015 at Kuchinoerabujima Volcano, Japan. The propagations of seismic waves were clearly recognized in F-net seismograms in southwest Japan. The excitation force of three eruptions was analyzed using F-net broadband seismometers. The analysis of source time functions of three-component single force shows that vertical force is dominant in the eruptions at 12:24 on Aug. 3, 2014, and at 12:09 on May 29, 2015 (local time). In addition to the vertical force, lateral force in the north-south direction was also dominant in the eruption at 9:59 on May 29, 2015. This suggests that the mechanism of this eruption is different from the other two eruptions. The lateral force may be related to the momentum exchange by the emission of deposits inclined to the north- south direction.

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This study analyzes the effectiveness of a disaster management plan and the problems encountered in its implementation, focusing on patterns of interaction between government and society in terms of disaster governance. Scholars in socio-political science point out that there has been a shift in the balance between government and society, from the public sector to the private sector as different sectors interact to solve problems. This study analyzes patterns of interaction and illustrates factors that influence the shift by examining the formulation and implementation process of an evacuation plan in the case of a volcanic eruption of Mount Shindake on Kuchinoerabujima Island, Japan. Mount Shindake explosively erupted on May 29, 2015. Immediately after observing the eruption, Japan Meteorological Agency (JMA) issued a volcanic alert “level five (evacuate),” the highest level. It was the first time that evacuation operations have been performed under such a high warning level. Although there were no official short-term warnings prior to the eruption, all people on the island evacuated safely. As a result of the study, we found that disaster governance had shifted from government-led to government and community collaboration after the volcanic eruption on August 3, 2014, which made the evacuation plan more effective.

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