Whether a large disaster could change public concern and risk perception: a case study of the 7/21 extraordinary rainstorm disaster in Beijing in 2012

Improving social concerns relating to floods and the perception of the public to risk can reduce the risk of urban flood disasters. This study investigates whether social concern regarding disaster is greatly increased by an extraordinary rainstorm, and whether such disasters change the public's risk perception and stimulate them to take effective disaster prevention measures. An extraordinary rainstorm disaster-known the 7/21 disaster-occurred in Beijing, China, on July 21, 2012. This resulted in 79 deaths and a direct economic loss of 11.64 billion RMB (approximately 1.80 billion USD). Using this disaster as an example, this paper analyzes Beijing's daily precipitation data in the 2012 and 2013 flood seasons and measures the degree of social concern before and after the disaster and the relationship between the degree of social concern and the precipitation intensity. The results indicate that the rainstorm rapidly increased the degree of social concern from 0.12 to 0.77; however, concern had stabilized by 2013 and was basically consistent with the precipitation amounts. A random sample of 181 people participated in a questionnaire survey. The results indicate that the level of public risk perception significantly increased post-disaster, with the degree of public concern regarding rainstorm risk and the number of people who implemented disaster prevention and preparedness measures being doubled. Moreover, approximately 75 % of the disaster prevention behavior involved observing early warning information and going out less, i.e., reducing exposure. But, this response was only a temporary adjustment phenomenon, lasting approximately 1 month: Entry-Transition on July 21 and Exit-Transition on August 30. Moreover, public behavior changes are limited to the year in which a disaster occurs: In the flood season of 2013, 62 % of the population did not appear to be affected by the 2012 precipitation results. Therefore, the majority of the public will not establish long-term risk prevention awareness as a result of an extraordinary disaster. Strengthening public awareness of disaster risk requires a long-term effort.