The Minato City Office in Tokyo has published maps on local area hazards, including tsunami risk, liquefaction and flood risk maps.
The overwhelming majority of Minato-ku, particularly everywhere west of Tokyo Tower is not at risk of a tsunami. The simulation is based on the Genroku Kanto Earthquake which is estimated to occur at intervals of around 2,300 years. The last one was in 1703. The probability within the next 30 years is almost 0%.
In the event of a tsunami, the following neighbourhood is at risk of between 0 ~ 0.50 meters of inundation:
- Kaigan 2 Chome
In the event that all tide prevention measures and floodgates fail and liquefaction occurs, some of the following neighbourhoods are at risk of between 0 ~ 1.5m+ of inundation in a tsunami:
- Kaigan 1, 2 and 3 Chome
- Konan 2 Chome
- Hamamatsucho 2 Chome
- Shiba 1 and 2 Chome
- Shibakoen 2 Chome
- Shibaura 1 and 2 Chome
Tsunami hazard maps:
Liquefaction can occur during an earthquake if the soil is or ground is weak. Examples of weak soil can include reclaimed islands, and land in swampy or former riverbed zones.
Areas with spots of high liquefaction potential include Shibaura, Kaigan, Konan, Shimbashi, Nishi-Shimbashi and parts of Toranomon.
Parts of Tokyo are at risk of flooding during heavy rainfall. This includes areas within Minato-ku which are at risk of flooding in the event that the Furukawa River or Arakawa River overflows, or if torrential rains are too much for the storm-water drains to handle. The severe rainfall events tend to occur between July and October.