抄録
The most obvious effect of earthquakes on the majority of building structures is exerted by the short-period ground shaking. Among factors exerting influence on short-period ground shaking, the source mechanism of the fault seems to be very important problem. But this problem is remaining unsolved yet. Recent fault studies show that a relatively simple elastic dislocation model of faulting can explain the long-period (longer than several seconds) portion of observed seismograms. So far as the simple dislocation model of faulting is adopted, however, it is very difficult to explain the short-period (shorter than several periods) portion of them.
