# Utilization of ICT as a Digital Infrastructure Concerning Disaster Countermeasures in Japan
## 1 Introduction  
In recent years, countermeasures for natural disasters have become a high priority all around the world due to the global increase in weather disasters such as typhoons and local torrential rainfall, as well as volcanic eruption, drought, heat waves and earthquakes. According to the White Paper on Disaster Management 2018 [1], among disaster countermeasures such as \"self-help\", \"mutual help\" and \"public help\", the most fundamental method is \"self-help\" which is a countermeasure individually conducted. It is important for each individual to have a high disaster prevention awareness in everyday life in order to minimize the damage through countermeasures, as rescue teams are not able to immediately reach all disaster victims during a disaster. Therefore, it is important to enhance the government's \"ability to inform\" and the public's \"ability to become aware\" by widely and appropriately providing disaster information, accurately grasping hazardous areas as well as evacuation centers in case of a disaster before it occurs, and accumulating disaster information with location information ([PERSON], 2016) [2]. In order for this to lead to \"mutual help\" and \"public help\", sufficient accumulation and sharing of disaster information within the local community including residents, corporations and the local government are essential during normal times. On the other hand, in recent years in Japan, a cloud computing society where the internet can be reached from various information tools has been established, and Japan has entered the age of Internet of Things (IoT) and Internet of Everything (IoE) in which various things can be connected to the internet. Based on such current conditions, the realization of a \"super-smart society\" was clearlyset up ahead of other countries as the first pillar in the 5 th Science and Technology Basic Plan (Cabinet decision, January 2016) [3], and a series of initiatives towards this realization is called the \"Society 5.0\". The society mentioned above is able to efficiently gather and accumulate disaster information as local knowledge made up of knowledge from the experience and everyday life of residents as well as the expertise based on scientific findings through the effective use of Information and Communication Technology (ICT) (Science Council of Japan, 2008; [PERSON] et al., 2012; [PERSON] et al., 2013) [4; 5; 6]. Based on the background above, the present author and her co-researchers worked together with local communities during normal times to develop a disaster information system as a countermeasure for damage reduction in disasters by integrating social media and Web-GIS in order to promote the utilization of disaster information as local knowledge ([PERSON] et al., 2015) [7]. Additionally, multiple information systems were integrated to develop a spatiotemporal information system. With the function of social media mapping, which is one of the most important functions, the submitted data on social media with location information were consolidated on a digital map of Web-GIS, indicating the utilization potential of using such information during disasters ([PERSON] et al., 2018; 2019) [8; 9]. Considering these circumstances, the present study aims to describe the utilization of ICT as a digital infrastructure concerning disaster countermeasures in Japan. Specifically, the present study will present the utilization potential of the above two types of systems which were developed integrating social media and GIS. Additionally, taking up Twitter as a familiar digital infrastructure, the present study will also present its utilization potential based on the case of the heavy-rain disaster in Western Japan in 2018 (from June to July in 2018). For this, Section 2 will introduce the results of preceding studies in the related academic fields, and demonstrate the novelty of the preset study. Section 3 will review the changes in the information communication environment in Japan from the 1990s onwards.