The government called for the creation of an electronic mapping system Thursday as part of measures to respond to a major earthquake in the Nankai Trough that may hit populous areas on the Pacific side of central to western Japan.
The measures in an interim report -- which the Ministry of Land, Infrastructure, Transport and Tourism adopted at the day's meeting and aims to finalize by March -- also feature specific steps in four timeline stages to counter the possible disaster.
On the mapping system, an e-map containing detailed geographical data would be updated with information on flooding, mudslides and other changes observed from satellites and helicopters, it said.
Analysis of "big data" such as mobile phones location information and postings on the Internet will also be utilized to get a picture of the movement of evacuees and traffic.
The ministry plans to first analyze the plains on which Nagoya and Osaka are located, on account of their heavy population concentrations.
In terms of its response timeline, the report said the government should prioritize protecting people's lives in the first three hours after the quake, while focusing on rescue activities and securing emergency transportation routes by the time 72 hours have passed.
It should turn to supporting disaster-affected people and local governments by the time seven to 10 days have passed and to reconstruction afterward, it said.
Also included is a five-year construction plan to enhance the traffic system in the district of Yui, Shizuoka Prefecture, where the Tomei Expressway, the JR Tokaido Line and National Route 1 run parallel on the coastline. As major traffic arteries linking Tokyo and Nagoya, any disruption to the routes would have major implications.
The land ministry will also consider countermeasures for large earthquakes occurring in series and strengthening cooperation with police and the Self-Defense Forces in finalizing the report.
The government estimates that a Nankai Trough quake would kill up to 323,000 people and cause 220 trillion yen worth of losses under the worst case scenario.