Nobuyuki Egusa

An Integrated Support System for Disaster Prevention Map-Making Using Town-Walk Information Gathering

Throughout Japan, numerous disaster prevention maps have been made over time using the method of town-walk. This method will assist in disaster prevention and enable a greater understanding of the disaster prevention field. The development of these maps increases disaster awareness, improves the self-help ability of individuals, and increases cooperation amongst local communities. Currently, there is a support system for developing conventional disaster prevention maps; however, no maps have been designed using the town-walk method. Therefore, in this paper, we present an integrated support system for making disaster prevention maps using the information gathered by the town-walk method. We conducted a comparison experiment between the proposed system and the conventional system (using paper maps). This experiment demonstrated that a consistent support function would be effective in developing disaster prevention maps using the town-walk method. We also confirmed that the proposed system improves disaster awareness among individuals, understanding of the area, and the conventional system.

Availability of Disaster Preparedness Awareness Improvement for Supplying Knowledge Using Microblog and Comic Expression

The Great East Japan earthquake that occurred in March, 2011 caused large-scale damage in the Tohoku area. Japan has frequently been geographically and economically damaged by natural disasters, such as the 2014 Mount Ontake eruption, 2015 Kanto and Tohoku heavy rain, and 2016 Kumamoto earthquake. In general, disaster preparedness awareness (DPA) increases immediately following a disaster; however, this preparedness diminishes over time. Therefore, the continuation and improvement of disaster preparedness of people is essential. To address this critical issue, we have distributed a “disaster preparedness four-frame comic (DPFFC)” to provide knowledge pertaining to disaster preparedness by using comic expressions via online social network Twitter. The DPFFC aims to improve the DPA by helping users to acquire related knowledge in their daily lives via Twitter. In this study, we considered the possibility that the DPFFC may continue and improve DPA by combining Twitter, which is used in daily life, with a comic, which provides a significant learning effect, and our results confirmed this. In addition, we found that the DPFFC has the potential bridge the gap between DPA and action.

Evacuation Support System for Everyday Use in the Aftermath of a Natural Disaster

Numerous natural disasters occur in Japan, such as earthquakes, typhoons, and volcanic eruptions. Information technology is expected to facilitate evacuation support when a disaster strikes, but networks cannot be used in many cases. Moreover, if a disaster occurs in a town that people do not frequent often, they may find it difficult to cope initially. It is difficult to access software online immediately at the time of a disaster. Thus, we have developed an evacuation support system called AkariMap, which can be used offline in the aftermath of a disaster. AkariMap is also a system that is suitable for everyday use. AkariMap has two functions: a function that notifies a user about evacuation support information each day and a disaster mode function that users can access at times of emergency. Based on the results of our experiments, we report the following findings. (1) Subjects increasingly accessed local evacuation support information for about 10 days. (2) Even if people did not use the notification function in the long-term, they were still accustomed to using the system. (3) If people need to find a shelter using AkariMap, they can identify a safer shelter by displaying the flooded areas.

Physical and Dynamic Properties of Soil Cement Diaphragm Walls and Seismic Performance Evaluation Using Seismic Response Analysis

本研究では, 廃棄物処分場等の鉛直遮水工として適用されることが多いソイルセメント系連続地中壁の物理・力学特性に関する種々の室内試験を実施するとともに, 地震応答解析によりソイルセメント系連続地中壁の耐震性能評価を行った。その結果, 1) ソイルセメント連続地中壁は, 兵庫県南部地震クラスの巨大地震 (レベル2地震動) に遭遇すると, 引張強度不足に起因してクラック等が発生し遮水機能が大幅に低下する可能性があること, 2) ベントナイトの混合比率を大幅に増加させることによって, 固化後でも塑性状態を維持し得るソイルセメント・ベントナイト連続地中壁の造成が可能となること, 3) ソイルセメント系連続地中壁の耐震性能評価を行う場合, ソイルセメント連続地中壁では引張応力に対する安全率に, またソイルセメント・ベントナイト連続地中壁ではせん断応力に対する安全率に着目すればよいことを明らかにした。

NUMERICAL SIMULATION ON NATURAL ATTENUATION OF CHLORINATED ETHENES IN AN AQUIFER

In order to evaluate the natural attenuationof chlorinatedethenes, especially trichloroethylene (TCE) anddichloroethylenes (DCEs) in an aquifer, the effects ofdispersion-and-dilution and biodegradation on the concentrations of TCE and DCEs were investigated using numerical simulation. The resultsobtained in this study can be summarized as follows: (1) In an aquifer with high biodegradation rate of DCEs (first order rateconstantof DCEs is over 2.0×10-3/d), the concentrationratioof DCEs to TCE is less than 1.0. (2) In an aquifer with highdispersion-and-dilution rate (groundwater velocity is over 0.6m/d-1.0m/d), the concentration ratio of DCEs to TCE is less than 1.0. (3) When the first order rate constantof DCEs is less than 1.0×10-3/d and the groundwater velocity is less than 0.4m/d-0.7m/d, DCEs tend to accumulate in an aquifer.