EARTHQUAKE OBSERVATION ON VARIOUS SOIL CONDITIONS AND ANALYSES OF THE RECORDS

An earthquake recording system in Sendai, Japan is introduced at first. The system includes ۱۱ observation sites and control station. Although the seismic activity around Sendai has not been so high during the period, a number of records with intermediate amplitude levels have been obtained so far. Using these records, we investigated the average properties and variations of maximum accelerations, amplification ratios of the response spectra between base and surface layers. Also the variations of the relationships of response spectral values between observation sites are also examined to see the effect of source locations and propagating paths. In addition to the analyses, a research project which are now underway using the earthquake records obtained here for quantitative definition of local site effects and determination of the site specific design earthquake ground motions for structures is also introduced