Japan has suffered many disasters, such as earthquakes, typhoons, torrential rains, and tidal waves. Recent disasters are still fresh in our minds. Examples are the Great Hanshin-Awaji Earthquake in 1995, and more recently, the eruptions of Mount Usu (March 2000) and Mount Oyama on Miyake Island (July 2000), the disastrous torrential rains of the Tokai region (October 2000), and Geiyo Earthquake (March 2001). Predictions of the possibility of a Great Tohoku Region Earthquake and an Inland Earthquake in the South Kanto Region are a cause of much concern.
In most cases, a disaster strikes without warning. When a disaster occurs, people at the stricken area are confused by the conflicting information they received from various sources. Understandably, the local population tends to panic.
It is necessary to transmit accurate disaster information to the people of a stricken area. At the same time, people outside the disaster area need prompt and accurate information on the scale of the disaster, the location and the conditions at the site. Equipped with such information, people can help people in the disaster area and work toward restoration of the area in ways that are viable.
The disaster radio systems built by the national and local governments are based on the experience gained in past disasters. The purpose of the radio systems is to secure a means to collect and transmit disaster information in the times of emergency.
The disaster communication networks in Japan consist of three levels. The first level is national level. The second level is prefectural local governments level, and the third level is local communities (cities, towns, and villages) level.
The core of the Central Disaster Radio System is the Cabinet Office. Including 26 central ministries, it consists of the appointed administrative organizations, the appointed public institutions (49 entities from such organizations as NTT, NHK, electric power companies), and disaster related organizations (9 entities including Tokyo Disaster Medical Center) in the Tachikawa Disaster Base.
This system is a communication network to connect the Fire Defense Agency and all the prefectural governments in Japan. It is used for mutual communications by telephone and facsimile and for broadcast from the Fire Defense Agency.
This system is a communications network which connects prefectures and local communities (cities, towns, villages) and the disaster related organizations. The purpose of the network is to collect and transmit information. Including a system which uses satellites, the Disaster Administrative Radio System is installed in every prefecture.
This system is a network in which local governments (cities, towns, and villages) collect information on disaster and communicate the collected information to the residents.
At the end of 2001, 65% of all the local governments of cities, towns, and villages (3,247) were equipped with the broadcast system, with 87% of all the local governments having the mobile system.
This system is a mobile network. The purpose of the network is to secure information from isolated areas with no means of transportation or communication and to secure communications between the organizations which are closely related to the local residents such as hospitals, schools, utility companies and local governmental offices such as city offices, town halls, and village offices. As of March 1998, 8% (247) of all the local governments (cities, towns, and villages) have this system.