千葉県東方沖地震による九十九里平野周辺の震度分布とその地質的震動区分  [in Japanese] The seismic intensities and their geological classifications in Kujukuri Plain and adjacent areas at The 1987 Eartquake off the East Coast of Chiba Prefecture, Central Japan  [in Japanese]

Using 4000 copies of a questionnaire, the author investigated the distributions of seismic intensities, the damage rates of roofing tiles, and the ground initial motions, in and around Kujukuri Plain. With the analysis of them, the author came to grasp the minute images and characteristics of the ground motions, and also found it possible to classify them into four categories as follows: (1) the motions relative to the direction of the earthquake fault, (2) the motions relative to the deep geological structures (e.g. Blocking structures), (3) the motions relative to the topographies or geological structures in shallow zones (e.g. on upland or on lowland), (4) the motions relative to the geological conditions of the ground surface or micro-topographies (p.g. on natural levee or on back marsh)