Professor Osamu Murao, Associate Professor Shuji Moriguchi and Associate Professor Akihiro Shibayama investigated the affected area in Kumamoto. Findings are summarized as follows:

・Most serious damages were found on old buildings and relatively small damages on new buildings

・Extensive damages were observed along the faults; especially heavy damages on houses with roof tiles

・It is necessary for key buildings such as city halls to have anti-seismic re-enforcement, to function as a disaster relief/evacuation center

・Having been damaged by direct-hit earthquakes, the disaster area has been expanding

Details:

The team found that visible damages were found intensively on houses built before 1981 when new quake-resistance standards became effective in the Building Standards Act, whereas there were relatively small damages found on newer buildings. There are still many houses which have not complied with current seismic design standards, not only in Kumamoto but also all over Japan.

The dangers of old wooden houses were already pointed out after the Hyogo Earthquake in 1995, but the 2016 Kumamoto Earthquake revealed that the problem has not been solved yet. It is a pertinent issue to be addressed, especially in consideration of the Nankai Trough Earthquake that may hit Japan in the near future.

The picture (upper right): An old wooden house that collapsed

The picture (left): A relatively new house stands without visible damage, next to an old wooden house that totally collapsed

Major building damages were found alongside the faults. Houses with roof tiles were severely damaged. Roof tiles are effective to withstand the strong wind of typhoons, but they work negatively in case of earthquake, as they add more weight to a roof.

Structures of Uto City Hall have been damaged, and City Hall can no longer function as the disaster response headquarters. Given the fact that other buildings around City Hall are not so seriously damaged, there is a possibility that the earthquake resistance of City Hall buildings were not enough.

The team infers that Uto City Hall was damaged because it was already an old building and because it was repeatedly damaged by aftershocks. It is necessary for key buildings such as city halls, hospitals and schools to have seismic reinforcement as they should function as important disaster prevention hubs when a disaster occurs. It is unfortunate that lessons from the damaged Kobe City Hall after the Hanshin-Awaji Earthquake have not been adopted.

In heavily affected areas, there are long queues at gas stations. Convenience stores are still closed, and traffic lights are off.

Due to frequent aftershocks with a seismic intensity of 5 to 6 on the Japanese shindo (shaking intensity) scale, citizens and municipalities have difficulties under a lot of stress. Earthquakes are direct-hit, aftershocks occur frequently, changing the area of strong quakes, which broadens the damaged area.

Landslides have already occurred in many places. The risk will increase by the rain forecasted today. Caution is needed particularly in areas hit by quakes with large seismic intensity. Evacuees must be feeling strong stress at the shelters, but heavy rain and wind forecasted tonight can damage buildings even more. Early voluntary evacuation is advisable if your house is in danger.

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