Dissertation research of graduate student Bruce Dore uses Twitter to understand patterns of emotional response to national tragedy and is discussed in multiple news outlets, including:
The Huffington Post
http://www.huffingtonpost.com/wray-herbert/the-national-sadness-of-s_b_6152132.html
Pacific Standard
http://www.psmag.com/health-and-behavior/from-sadness-to-anxiety-the-emotional-legacy-of-sandy-hook