Abstract
This study deals with the disaster of general urban districts composed by cell coordinate system. Although there were some works about special plants or structures with large risks until now, it might be investigated about the viewpoint for safety or risk of general urban districts. In this study, we attempt to use Bernoulli sequence as quantity of safety function and to use cell global coordinate system for first occurrence disaster. In addition, we examine the characteristics of its expansion with spread probability throughout simulations for next cells of disaster points after first occurrence disaster by using same conditions.
