Social sensing the 2018 Kīlauea Volcanic eruption through community Facebook use

There is a lack of understanding around the impacts and responses of communities receiving hazard and risk information during volcanic crises, but social media posts may be able to provide valuable insights. Using 7434 posts in a local residents’ Facebook group during the 2018 Kīlauea eruption, we track changes in social behaviour and emotional response. Eruption-related posts are dominated by information sharing and community observations. Sentiment and reaction analyses reveal an overall positive response, partly related to community support actions and local culture, despite the substantial detrimental eruption impacts. Temporal trends in the content of, and interactions with, posts can be linked to events during the eruption and actions taken by authorities, while the frequency of eruption posts decreases during hurricanes, indicating a shift in perceived risk in the community. Overall, results suggest social sensing with Facebook posts can provide insights on social actions and reactions during volcanic crises, but results differ from analyses of Twitter posts for the same event. More development of the techniques will be vital to gain full advantage of this promising approach.