Revaluation of accurate ground motion distribution in Sendai area during the 1978 Miyagi-ken Oki earthquake and damage distribution

本研究报告描述了从2003财政年度到2005财政年度为期3年的研究结果。本研究首先以仙台地区1978年宫城县大地震的准确地震动分布为基础，结合地震的最新知识和地质条件对地震的地震动分布进行了评价；二是明确地震时地震动特征与建筑物破坏特征的关系；第三，考虑受地表和地下深层结构等地质环境影响的地震动特征，研究建筑结构的抗震优化设计和抗震改造。2003财政年度，为了对不同土壤条件下地震时的地面运动特征和建筑物的性能进行观测评价，建设了地震观测网。在总共25个观测点上安装了小型地震仪（18个观测点……更多的观测点得益于基础设施、国土交通部的研究基金）。研究既有建筑结构抗震优化设计方法和改造优先度评价方法。在2004和2005会计年度，利用2005年8月16日宫城县大木地震和其他地震的观测记录，通过模拟分析，验证了基于近期地质信息构建的地下模型。在讨论了2005年地震与1978年地震的地震动特征差异的基础上，重新评价了1978年地震期间仙台地区的地震动分布。在长町、小岛町和神杉地区观测到的建筑物破坏特征与评估的地震动特征一致。此外，还研究了考虑地震动分布的建筑结构抗震优化设计和改造。建立了公共建筑抗震改造优先评价体系，为市政府负责人提供支持。少

This research report describes the results of a 3-year research, from the fiscal year 2003 to 2005. The research aims first to make an accurate ground motion distribution in Sendai area during the 1978 Miyagi-ken Oki earthquake, which was evaluated based on the recent knowledge of the earthquake and the geological circumstances ; second, to clarify the relation between ground motion characteristics and building damage features during the earthquake ; and third, to investigate the optimal seismic design and seismic retrofit of building structures considering ground motion characteristics affected by the geological circumstances, including surface layers and the deep underground structure.In the fiscal year 2003, an earthquake observation network was constructed in order to evaluate observationally ground motion characteristics and buildings' behavior during earthquakes in different soil conditions. At the total number of 25 observation points small seismometers were installed (18 points … More thanks to the research fund of the Ministry of Infrastructure, Land and Transport). An optimal seismic design method and retrofit priority evaluation method of existing building structures were investigated.In the fiscal years 2004 and 2005, the underground model constructed based on the recent geological information was verified by means of a simulation analysis using the observation records of the 2005/08/16 Miyagi-ken Oki earthquake and other earthquakes. After discussing the difference of ground motion characteristics of the 2005 earthquake and the 1978 earthquake, the ground motion distribution in Sendai area during the 1978 earthquake was revaluated. Building damage features observed at Nagamachi, Oroshimachi, and Kamisugi areas became consistent with the evaluated ground motion characteristics. Furthermore, optimal seismic design and retrofit of building structures considering the ground motion distribution were investigated. A seismic retrofit priority evaluation system of public buildings was developed for supporting municipal government officials in charge. Less