Abstract
In order to investigate the slightly-long-period microtremors, the measurement of microtremors at the seaside region and the periodical observations of microtremors over two years at the basin of inland have been carried out. It is conjectured that the slightly-long-period tnicrotremors are due to natural disturbances such as the swell of the sea.
Microtremors are affected by sea waves even at the region 60km away from the seashore, but the microtremors on the deposit change in the same manner as ones on the hill. The ratio of mean amplitude on the deposit to one on the hill is almost constant for each site. The ratio corresponds to the amplification degree of earthquake movements by each deposit. This ratio is useful for geophysical exploration and seismic hazard analysis.
