Earthquake resistance of buildings in Japan and risk of earthquake depending on the area
In Japan, Building Standard Act has been strictly reviewed every time we experienced a large earthquake.
All buildings are strictly required to have an earthquake resistance structure. Without rigorous compliance to earthquake proof standard set by a low, one can never get an approval of construction of a building from a public administration office in Japan.
It is said that the collapse ratio of the building as a result of a powerful earthquake is extremely low in Japan compared to any other countries. Transition of building regulations and earthquake resistance standard by generations
1st generation – buildings before 1971
2nd generation – buildings after 1971 and prior to 1981
3rd generation – buildings after 1981
4th generation – buildings after 2000 (As to wooden structures)
1971
After the earthquake off the
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The ground investigation became virtually mandatory.
2009
The Licensed Architect Act was revised as a result of the falsification matter of structural calculation discovered in 2005. The new law required all larger buildings than set on the standard to be structurally designed by a constructional design 1st class registered architect.
Most of buildings collapsed in the Hanshin-Awaji earthquake in 1995 were built before the New Anti-Seismic Design Standard came in effect. As explained here, the standard of earthquake resistance has been tightened every time the law was revised.
Level of earthquake resistance by structure of building
Earthquake Resistant Structure
It is the most common structure for detached houses in Japan. All buildings built after 1981 must conform to the New Anti-seismic Structure Standard requiring buildings to have an earthquake resistance