First, Old Japanese home means that it was built in the late 1940's as almost NOTHING survived the war in any large cities.
Originally Posted by Paul Brubacher
Two major problems occur with these homes and earthquakes;
First, they have very primitive foundations, often if they are concrete it is very small, usually almost on the surface only and very thin, very little if any rebar, and they homes are not very well secured to said foundations. It is not uncommon to see an old house that survived the quake intact, but has to be demolished afterwards as it has jumped off it's foundation, this happened to several homes in my area after the March 2011 quake.
Second, they have a HEAVY tile roof, they are designed to stop fire from spreading and to stay in place during typhoons, OK that might be a good idea in the 1800's but why are so many NEW homes still made with these heavy tile roofs? Tradition, that is what a roof should look like I guess, also the roof tile company does not want or is able to switch to asphalt shingles. These roofs are heavy, and when a big quake hits, with them sitting on top of an old wooden framed home, well a lot of them fall down, they don't have proper shear walls in the old homes, so they crash down like a house of cards.
It is also fair to note that during the late 1940's and early 1950's there was a frenzy of construction, and not everything was built well, people just needed homes to live in, no one imagined that these homes would still be around 70 years later.
The pessimist complains about the wind; the optimist expects it to change; the realist adjusts the sails.
William Arthur Ward