Co-occurrence network of frequently occurring words. Each group of words connected by dotted lines indicates a cluster of words (topic) used closely in sentences. The following six topics were extracted: (1) situation of Yamakiya district before the accident; (2) agriculture and satoyama usage before and after the accident; (3) evacuation and life at temporary house; (4) radiation and radioactivity; (5) administrative actions at the accident; (6) decontamination in forest and farmland.