April 14 marks the first anniversary of the beginning of the Kumamoto Earthquake disaster, which saw a pair of temblors register up to 7 on the 7-point Japanese intensity scale.
Emergency measures to respond to the disaster, including the construction and provision of temporary housing, have almost been completed. However, the number of confirmed cases of quake-related deaths has kept growing, reaching 225 including 50 who died as a direct result of the disaster and five who died from the ensuing torrential rains and mudslides in disaster areas. It is indispensable to provide medium- and long-term assistance to survivors.
At the same time, it is necessary for people across the country to face up to the risks of active faults that can trigger serious earthquakes and be prepared for possible serious temblors in the future.
The government conducted surveys on major active faults across the country following the January 1995 Great Hanshin Earthquake, which devastated Kobe and surrounding areas as well as Awaji Island in Hyogo Prefecture. Based on the results, the government announced the estimated likelihood of these faults causing quakes.
Following the 1995 quake, the government estimated that at a maximum probability of 0.9 percent the Futagawa fault zone, which triggered the main shock in the Kumamoto earthquakes just two days after the foreshock, would cause an earthquake as large as magnitude-7 within the next 30 years.
Experts regarded the figure as a bit high and called for close attention to the fault's activity. Nevertheless, local residents said shortly after the disaster that they had not expected that such a powerful temblor would hit Kumamoto. The government's warning had not reached out to the local community.
Following the Kumamoto Earthquake, the government's Headquarters for Earthquake Research Promotion classified the probability of active faults causing earthquakes into four levels ranging from S (high) to X (unknown) and decided not to place emphasis on specific percentages. However, this is just a superficial change.
The Education, Culture, Sports, Science and Technology Ministry and the Japan Meteorological Agency have compiled leaflets showing the positions of major active faults in each region and predicting the intensity of earthquakes these faults could trigger, and began holding briefing sessions for local government officials in charge of disaster management in Tokyo and Osaka. These efforts should help increase awareness among local bodies and residents of the need to be prepared for possible serious disasters.
Needless to say, earthquakes could cause damage to areas that are not close to the active faults that trigger them, depending on the areas' geographic features and characteristics of the ground.
Still, if major active faults are to move, it would certainly cause intense temblors in surrounding areas. Thus, the government should notify residents of the existence of active faults near where they live and encourage them to increase the quake-resistance of their homes.
The Land, Infrastructure, Transport and Tourism Ministry has shown the assumed positions of active faults in Mashiki, Kumamoto Prefecture, which was hit hard by the April 2016 quakes, and urged the municipal government to take the faults' positions into consideration in reconstruction work. The municipal government's disaster recovery plan also calls for "coexistence with active faults."
Since around 2,000 active faults are known to exist in the Japanese archipelago, coexistence with active faults is a common national challenge.