Visualization is one of the most important techniques for examining influences of various kinds of phenomenon such as natural disasters, public gatherings, or accidents on changes in behavior of Metro system passengers. In this paper, we visualize the propagation of the effect of troubles and changes in transportation flows in a wide area using data on the Tokyo Metro extracted from a smart card system from March 2011 to April 2013. Our system enables us to not only explore changes in passengers' actions after accidents or disasters but also to discover unusual and unexpected phenomena and explore their details and reasons.