Tsunami Countermeasures in Japan 1999 Tohoku University Dr. Fumihiko Imamura Asian Disaster Reduction Center Taichi Kusaka

General Overview of the historical tsunamis The first recorded tsunami is the 684 AD Hakuhou earthquake tsunami. Since that time, more than 200 tsunamis have been generated by earthquakes, volcanoes and landslides in the all area of Japan, from Hokkaido to Okinawa. In addition, about 50 tsunamis propagating from far field in the Pacific Ocean have affected Japan. Although the frequency of tsunamis is much smaller than those of earthquakes, damages by a tsunami is larger and a damaged area is much wider, once a tsunami takes place.

Major tsunami disasters in the past - Japan

Tsunami Story in education l Fire of rice straw stack (Inamura-no-hi) –About 150 years ago a man in Wakayama warned villagers of tsunami incoming and led them to the evacuation site by putting fires on rice straw stack and saved many lives. –He later made sea walls along the coast. –This story was taught at school using textbooks.

Tsunami Forecasting The Japan Meteorological Agency(JMA) makes an announcement of tsunami forecast, including location of epicenter, magnitude of earthquake, occurrence of tsunami and its scale, when it observes earthquakes in coastal and ocean areas. JMA constructed 150 tsunami/earthquake observation facilities all over Japan in order to issue tsunami warnings within 3 minutes after the local earthquakes. The system was improved after the Hokkaido-Nanseioki Earthquake (Okushiri Tsunami) in 1993.

Swift Communication Tsunami forecasts are immediately conveyed to each district branch and observatory of Meteorological Agency by way of forecast/warning simultaneous transmission system, online and meteorological satellite, Himawari, and also provided to disaster prevention organizations and press/media which has receiving terminals. The forecast/warning is relayed to residents and ships from each organization.

Communication Routes by the Meteorological Administration Law

Improvement in Forecast Accuracy JMA started the new system for tsunami forecasting from 1999 based on the forecasting technology utilizing numerical simulation of tsunamis and other researches with the experts and concerned organizations. Given an earthquake information of the magnitude, location, fault parameters, numerical simulations on generation and propagation of tsunamis stemming from earthquakes is conducted firstly with inputting topography of ocean floors and coastal areas, which provide the quantitative information of tsunami along all coastal area. When an earthquake occurs, the wave height and arrival time of the tsunami are announced in specific numerals by searching the results of such calculations.

New Tsunami Forecasts from 1999 By this method, the following was made possible. 1) Quantitative data Announcement of the specific tsunami wave height in meters, which used to be described such as “3 meters plus at higher locations” 2) Detail information Tsunami forecasting zones of Japan were segmented from the former 18 to 66. See the map below.

66 Tsunami Forecasting Zones

Infrastructure As protection facilities against tsunamis in coastal regions, sea walls, break waters, tide gates, tsunami bay-mouth breakwaters, etc. have been constructed. Constructions of these facilities are planned and designated by the government as coastal protection facilities project. The Ministry of Agriculture, Forestry and Fisheries, Ministry of Transport and Ministry of Construction have formed the Coordinating Council for Coastal Areas Preservation where coordination of projects are being conducted.

Surveillance With the Nihonkai-Chubu (Japan Sea) Earthquake in 1983 “Tsunami Warning Inter-Ministry/Agency Conference” was formed in June 1983 to promote tsunami countermeasures by the 7 ministries/agencies: Prime Minister’s Office, National Police Agency, National Land Agency, Maritime Safety Agency, Meteorological Agency, Ministry of Posts and Telecommunications, Fire and Disaster Management Agency. On 15 July 1983 the conference agreed on a note of “Tsunami Surveillance in Coastal Areas” and revised it in light of the tsunami disaster from the Hokkaido-Nanseioki Earthquake in 1993 on 24 November By this, the government decided to promote tsunami surveillance by immediate tsunami warnings and evacuations.

Comprehensive Tsunami Countermeasures 1. Manuals (1) “Guidance for Tsunami Countermeasures in Disaster Prevention Local Plan” (2) “Tsunami Disaster Forecasting Manual” 2. Database “Tsunami Inundation Forecast Database”

Guidance and Manual (1) Generally speaking: In tsunami disaster prevention, each coastal area needs specific countermeasures such as construction of sea walls, evacuation routes, etc. in accordance with each local plan because tsunamis vary in wave height, arrival time, appearances, damages, etc., according to the local situation.

Guidance and Manual (2) In order to promote tsunami countermeasures suitable for each coastal areas by comprehensive planning under the coordination of the concerned organizations Agencies (National Land Agency, Ministry of Agriculture, Forestry and Fisheries, Fisheries Agency, Ministry of Transport, Meteorological Agency, Ministry of Construction and Fire and Disaster Management Agency) jointly developed “Guidance for Tsunami Countermeasures in Disaster Prevention Local Plan” in March 1998 and presented the basic ideas and policies for tsunami disaster prevention and the process of making such plans.

Guidance and Manual (3) Agencies (National Land Agency, Meteorological Agency and Fire and Disaster Management Agency) jointly prepared “Tsunami Disaster Forecasting Manual” in March 1998 and presented the method of tsunami inundation mapping as it is important to display the inundation risk areas on the maps in order to assess local tsunami risks beforehand by using new tsunami forecasting after These guidance and manuals are distributed to local governments and municipalities to promote comprehensive tsunami disaster prevention.

Tsunami Inundation Forecast Database The National Land Agency developed the database in order to forecast tsunami inundation zones in coastal areas and the earthquake damage early estimation system in order to estimate tsunami damages in those areas at early stages, in response to the new tsunami forecast effective from The operation of the system started in This database is expected to be utilized in preparing tsunami inundation maps by municipalities in accordance with the manual stated above.

Inter-Ministry Conference In November 1998 the former Inter-Ministry/Agency Conference for Tsunami Warning was reformed to the new “Inter-Ministry/Agency Conference for Tsunami Countermeasures” with the view of promotion of disaster prevention measures including coastal reinforcements, evacuation and rescue under the concerned ministries/agencies coordination. The member organizations are 11 ministries/agencies: Prime Minister’s Office, National Police Agency, National Land Agency, Maritime Safety Agency, Meteorological Agency, Ministry of Posts and Telecommunications, Fire and Disaster Management Agency, Defense Agency, Ministry of Agriculture, Forestry and Fisheries, Ministry of Transport and Ministry of Construction.