Table 2 List of the topic labels and the top 10 most important words from the term frequency-inverse document frequency (TF-IDF) for each cluster
Cluster # | Top 10 words | Topic label |
|---|---|---|
1 (anniversary) | regulation, mountaineering, lift a warning, Otaki (place name), village, tourism, a mountain cabin, summit, investigation, town | Mt. Ontake’s volcanic warning status |
2 | evacuation, plan, research, (warning) level, prefecture, the bereaved, disaster prevention, municipality, earthquake, Kusatsu (place name) | Municipalities’ volcanic emergency plans |
3 (anniversary) | search, commemoration, volcano, regulation, Otaki (place name), the bereaved, photo, eulogy, disclosure, Nagano (place name) | Human interest |
4 | (Mt. Ontake Volcano) Meister, Kiso (place name), climbing, prefecture, (evacuation) shelter, research, disaster prevention, consider, plan, evacuation | Lessons learned from the 2014 Mt. Ontake eruption |
5 | advance team, shelters, investigation, Gifu (place name), Nagano (place name), establish (a task force), volcano, family, a prefectural governor, send (a rescue team) | Searching for missing persons |