Text vs. Images: On the Viability of Social Media to Assess Earthquake Damage

In this paper, we investigate the potential of social media to provide rapid insights into the location and extent of damage associated with two recent earthquakes - the 2011 Tohoku earthquake in Japan and the 2011 Christchurch earthquake in New Zealand. Concretely, we (i) assess and model the spatial coverage of social media; and (ii) study the density and dynamics of social media in the aftermath of these two earthquakes. We examine the difference between text tweets and media tweets (containing links to images and videos), and investigate tweet density, re-tweet density, and user tweeting count to estimate the epicenter and to model the intensity attenuation of each earthquake. We find that media tweets provide more valuable location information, and that the relationship between social media activity vs. loss/damage attenuation suggests that social media following a catastrophic event can provide rapid insight into the extent of damage.