In Japan, the Building Standards Law was revised in 1981, and buildings constructed before that year are referred to as “old seismic” while those built after are called “new seismic”.

Buildings constructed before 1981 were designed to withstand earthquakes of up to magnitude 5 on the Japanese seismic scale, while those built after 1981 were designed to withstand earthquakes of up to magnitude 6-7 on the same scale.

The background of changing the Building Standards Law is Miyagi Prefecture Earthquake in 1978 (magnitude 5) which caused extensive damage due to collapsed buildings and damaged block walls, then the new earthquake resistance standards were introduced on June 1, 1981.

In 1995 January 17, the Great Hanshin-Awaji Earthquake (magnitude 7) killed 6,434 people. 90% of deaths were due to crushing by collapsed houses. A post-earthquake survey surprisingly revealed that 98% of the damaged wooden houses were built by the old earthquake resistance standards. If all of these buildings had met current seismic standards, there would have been fewer casualties.

The current new earthquake-resistance standards have been in effect since June 1, 1981, so if it’s a newly built or used home that’s less than 40 years old, it’s basically considered to have been built to the new earthquake-resistance standards. However, when purchasing a property that is older than that, it is important to pay close attention to earthquake resistance standards.

However, when purchasing a building that is nearly 40 years old, it is better to check the building confirmation date instead of the completion date or construction date. This is because whether a building is built according to old or new earthquake resistance standards is determined by the date the building certification application is received at the government office.

For example, even if the completion date of the building is October 1981, if the building confirmation date is October 1980, it is likely that the building was built to the old earthquake resistance standards. The building age is a number that indicates the number of years from the completion date to the present, so in some cases it may not be enough to determine the earthquake resistance standards based on that alone.

Especially when it comes to condominiums, the dealing properties are older than single-family homes. Originally, the structural lifespan of reinforced concrete construction is estimated to be over 100 years, so depending on the actual seismic resistance and management conditions, some condominiums may be fully livable even if built to the old earthquake resistance standards.

If you have any further questions or requests, please feel free to contact to the following e-mail address.

【REDS】Real Estate Distribution System (REDS) Japan

Hiroki Kano (Mr.)

mailto: hi.kano@red-sys.jp