254 ECONOMIC GEOLOGY 
Similarly in the earthquake of 1923 motor cars at Yoko- 
hama were tossed into the air and fell upside down, and houses 
near the edge of a cliff were flung over it. 
Fortunately the meizoseismic area of most earthquakes 
is comparatively small. The main damage in districts 
farther from the origin is due to the yielding of insecure 
foundations, to the collapse of buildings of unsuitable design, 
or to fire or earthquake wave. 
Anti-earthquake building design has been based upon two 
opposite principles. The first aims at keeping the structure 
so light and elastic that it withstands shaking like a basket ; 
the other plans a structure so firm and rigid that it is as 
difficult to shake to pieces as a box. The basket system 
was tried in Japan, but was unsatisfactory, as though the 
building was safe, the play of the framework cracked the 
plaster, overthrew light objects, and created terrifying noise 
and dust. Extreme rigidity has been secured by interlocking 
bricks and strong ties, which must be broad to prevent them 
cutting the structures attached to them. Thus in 1880 a fire 
destroyed part of Yokohama, and left the brickwork chimneys 
as isolated stacks. They were uninjured by a subsequent 
earthquake, when adjacent houses were destroyed by the 
fall of the chimneys, which were cut through by the bands 
that attached them to the floors. 
C. Loose versus Firm Founparions—There has been 
much discussion as to whether a loose or firm foundation 
is the safer. A loose foundation may absorb the shock. 
Milne found that the vibration caused by the fall of a weight 
of 2000 1b. from a height of 35 feet on to soft ground was 
barely perceptible 40 feet away, whereas the same blow on 
hard clay produced a dislocation of about zisth of an inch 
at 250 feet away. In the Tokyo Earthquake of 1923 of 
buildings on hard soil only 6 per cent. collapsed, as against 
10 per cent. of those on soft soil ; but on hard soil 88 per cent. 
suffered some injury as against 81 per cent. on soft soil. 
Many attempts have been made to protect buildings from 
earthquakes by a free foundation. As Japanese light- 
houses suffered from the scattering of oil from the lamps 
during earthquakes Stevenson designed a lighthouse resting 
on a platform of cannon balls, hoping that their movement 
might absorb the vibration. The lighthouse was freed from