Research of the Geiyo Earthquake in 2001

结果表明：①2000年10月6日下午，日本西部鸟取地震发生后，日本西部地震活动开始活跃。2)对Geiyo地震两条剖面的Q值估计表明，通过俯冲菲律宾海板块的路径衰减较低。3)利用日本西部广岛平原及其周边的精确测量数据，对该地区基底地形进行了三维重力反演。值得注意的是，平原西部边缘存在一个北东-南南西向的槽状洼地，那里的房屋受损非常严重。(4)在对本次地震主要影响地区中国和四国的地震烈度进行问卷调查的基础上，通过问卷调查估计出许多地区的地震烈度高于仪器测量的烈度。库尔和库驰地区较多的墙体和坡面坍塌与地形地质特征和观测到的地震运动特征密切相关。(6)山坡居住区木结构房屋的屋面瓦破损情况与填切地面情况吻合。由于微颤测量，充填体和切割体的动态特性存在差异。此外，第二次抗震诊断方法必须考虑脆性柱或剪力破坏柱，以引导两栋钢筋混凝土学校建筑的抗震诊断结果及其地震破坏。7)虽然对公用设施生命线的物理破坏总体上不具有灾难性，但却出现了功能性破坏的蔓延，这是典型的城市地震灾害。8)调查了广岛县地震后主要由民众、地方政府和私营企业所表现出的社会反应。少

The conclusions can be summarized as follows :1) It is shown that the earthquake activities of western Japan have became active after western Tottori Earthquake occurred on the afternoon of Octobcr 6, 2000. 2) Estimates of the Q value for two profiles from the Geiyo earthquake, show that the attenuation is lower for the path that pases through the subducting Philippine Sea slab. 3) 3D gravity inversion of basement relief in the Hiroshima plain, western Japan, was performed using precise data measured in and around the plain. It is important to note that an NNE-SSW oriented trough-like depression is revealed to exist along the western edge of the plain, where damage to houses was remarkably severe. 4) On the basis of the questionnaire survey on seismic intensity in whole Chugoku and Shikoku areas mainly affected by this earthquake, the fact that higher seismic intensities than the instrumental ones were estimated in many areas by the questionnaire survey. 5) Collapse of stone retaining … More wall and slope surface collapse in cases of Kure and Kouchi districts respectively were strongly related to topographical and geological features and characteristics of observed earthquake motions. 6) The roof-tile damage of wooden houses in the residential area of hill-side looks to coincide with ground condition of cut or fill. Difference in dynamic characteristics due to micro-tremor measurement has been found between fill and cut. Moreover, the second earthquake resistance diagnosis method must be taken into account of brittle columns or shear-failed columns, in order to lead the results of earthquake resistance diagnosis of two reinforced concrete school buildings and their damage by the earthquake. 7) Although the physical damage to utility lifelines was not catastrophic as a whole, there occurred functional damage spread, which is typical of urban earthquake disaster. 8) Social responses shown by mainly people, local govemments, and private enterprises in Hiroshima prefecture after the earthquake are investigated. Less