Citizens' social media use and homeland security information policy: Some evidences from Twitter users during the 2013 North Korea nuclear test

• Current study examines homeland security policy issues.
• We analyze some risk communication networks emerged from Twitter users.
• The response to the 2013 nuclear test in North Korea was chosen as research topic.
• Citizens' risk communication is formulated through social media over time.
• The dynamic evolution of risk communication networks had important policy implications.

In the era of Web 2.0, managing risk communication on social networking sites has increasingly become crucial and complicated issues in the field of homeland security. The response to the 2013 nuclear test in North Korea was largely based on a coordinated effort by Korea's Ministry of Defense, the United Nations, and many countries from around the globe. By analyzing risk communication networks emerged from Twitter users for the period from January 30 to February 24, 2013, this study investigates the way in which citizens' risk communication is formulated through social media and how they transmit risk information in homeland security. Analysis results show the dynamic evolution of risk communication networks based on influential actors with critical information who played pivotal roles in distributing this information to other actors.