抄録
The strong ground motion during the future large earthquakes have been evaluated at Yokohama, the coastal alluvial deposit site, for aseismatic design of a high-rise building synthesizing the moderate seize earthquake records observed at the site. From the engineering point of view, selected the future earthquakes to be the recurrence of 1923 Kanto earthquake and hypothetical Tokai earthquake which was reported by Land Agency. Since the site is very close to the 1923 Kanto erthquake fault plane, we utilized three element earthquakes to get rid of the effects of propagation paths. While, in the case of Tokai eathquake, only one element earthquake was used because the epicentral distance is more than 100 km and in such a situation, it was thought that the effect of source mechanism may be neglected. If we assign the Neogene rock to be the free surface at the site, the maximum ground acceleration and velocity for kanto and Tokai eathquakes were found to be 330 Gal, 40 cm/s and 115 Gal, 20 cm/s respectively. The derivings agree well with maximum acceleration of 1923 Kanto earthquake deduced from the damage rate of wooden houses. Numerous observed data obtained near the focal regions are also in favor our results. Through the study, we came to the conclusion that the reexamination of the present status of earthquake loading system for the aseismatic design of structures is necessary. Thus, we propose the methodology of estimating the eathquake load and level of the ground motion. Since our methodology may not be complete, because there remains a lot of problems to be solved, we will try to improve our methodology by introducing the new findings in the future.
