This study investigated emotional contagion on social media following a natural disaster, using data from the 8-13 flash flood in Longcaogou, China. A dynamic model was developed to analyze emotional spread and simulate intervention strategies. Results showed negative emotions were more persistent and contagious than positive emotions. Reducing negative posts by half could decrease negative comments by 14.97% and positive comments by 7.17%. Simultaneously reducing negative and increasing positive posts further improved the ratio of positive to negative comments. The findings offer theoretical and practical implications for managing online public opinion after disasters.
