  Sociological studies on transnational migration are often based on surveys or
interviews, an expensive and time consuming approach. On the other hand, the
pervasiveness of mobile phones and location aware social networks has
introduced new ways to understand human mobility patterns at a national or
global scale. In this work, we leverage geo located information obtained from
Twitter as to understand transnational migration patterns between two border
cities (San Diego, USA and Tijuana, Mexico). We obtained 10.9 million geo
located tweets from December 2013 to January 2015. Our method infers human
mobility by inspecting tweet submissions and user's home locations. Our results
depict a trans national community structure that exhibits the formation of a
functional metropolitan area that physically transcends international borders.
These results show the potential for re analysing sociology phenomena from a
technology based empirical perspective.
