some much older houses just sit on the fundations, not bolted down. a house
in Berkeley was shaked off the foundation after a quake several years back.
some much old houses(as in Sunset district, San Fran), their walls were
not built to stand against latteral movement, which happens in an earth
quake. it depends on how old is the house.
Just like someone posted above. New house is better designed for earth
quake.