Virtual Earthquake Reconnaissance Team (VERT) Summary by Ezra Jampole, Sahar Derakhshan, and Kristen Hess.
Much of the existing housing stock in Japan is wooden. According to the World Housing Encyclopedia, in 1993, 68.1% of housing units were wooden, but this has decreased with newer construction. Much of the existing housing stock is load-bearing timber frame post and beam construction. Lateral loads are resisted by shear walls. Diagonal bracing is uncommon because of cracks that can appear in sheathing. Story heights are similar to those in the United States (2.8 meters). Houses typically are constructed on shallow foundations of reinforced concrete strip footings.
Click here for a video of typical light frame construction in Japan.
Statistics on housing in Japan were last produced for the 2013 Housing and Land Survey, found here, and include information on types of dwelling, construction materials, construction dates, and number of stories.
The 1995 Kobe, Japan earthquake typically caused damage to houses constructed prior to the 1980 building code. Post and beam construction was particularly vulnerable in areas where the peak ground acceleration has higher than 0.6g, while modern balloon framing had experienced far less damage in these areas (Rainer and Karacabeyli, 2000). Maly and Shoizaki (2012) reported that 240,000 houses were destroyed by the 1995 earthquake, mainly in dense low-rise areas with many older homes. Numerous fires broke out after the earthquake. Many wooden houses collapsed or were damaged by liquefaction.
Impacts to communities were profound. 220,000 people were housed in single story steel barracks, mainly in inconvenient locations on the outskirts of cities. The recovery was mainly government-driven public housing. People were forced to live far from their previous neighborhoods and found it difficult to resume their daily lives without their previous communities and networks. In early 1998, 45% of the temporary housing units were still occupied (Maly and Shoizaki, 2012).
According to the World Housing Encyclopedia, it was not common for the older buildings to be retrofit after the 1995 earthquake.
