Abstract
In order to produce a detailed seismic intensity map which aids regional disaster planning, a seismic intensity survey using paper-based questionnaire was conducted at Tsurumi ward, Yokohama in the northwestern Chiba earthquake (M6.0) on July 23, 2006. About 8, 000 questionnaire sheets were distributed and more than 3, 000 were collected. From the survey, the detailed seismic intensity distribution was revealed, showing that the distribution is very complex and that the intensity at a lowland is not necessarily larger than that at a plateau. To interpret the complex intensity distribution, the relation of the intensity with the ground condition is examined.
