Spectral characteristics of earthquake input motion on the base rock

(1)Hogoken-Nanbu地震上发生冲击波的可能性为弄清Hogoken-Nanbu地震的地震波中是否存在冲击波，对具有代表性的强震地震仪进行了冲击波试验，考察了冲击波到达地面时的声级。通过对北海道龟鸣国小盆地余震波的模拟，考察了不同方法的二维地震波模拟程序对地震波传播的适用性。验证了该程序较好地模拟了盆地边缘产生的面波。(3)基岩特征的形成分析了Hogoken-Nanbu地震和Kocaeli地震时基岩现场观测记录。计算了每条记录的速度反应谱的递推公式，并与现有的经验设计谱进行了比较。结果表明，与经验频谱相比，断层附近的重现频谱具有很大的长程波幅。

(1) Possibility of a shock wave on The Hogoken-nanbu EarthquakeTo make clear whether a shock wave had existed or not in seismic wave due to The Hogoken-nanbu Earthquake, the shock wave tests has been carried out regarding the representative strong motion seismographs and the acoustic level has examined when the shock arrived at ground surface. Consequently, it may be concluded that exist of shock wave is not realistic.(2) Applicability of 2-D wave simulation program using different method2-D simulation program for seismic wave propagation using different method was examined through the simulation of aftershock waves at the small Kaminokuni basin, Hokkaido. It was confirmed the surface wave produced at margin of basin was well simulated by this program.(3) Formulation of special characteristics on base rockObservation records at rock site during The Hogoken-nanbu Earthquake and The Kocaeli Earthquake were analyzed. The recurrent formula has been calculated for the velocity response spectra of each record and compared with the existing empirical design spectra. The results show the recurrent spectra at near the fault have very large amplitude in long range in comparison with the empirical those.