  Terrorists use violence in pursuit of political goals. While terror often has
severe consequences for victims, it remains an open question how terror attacks
affect the general population. We study the behavioral response of citizens of
cities affected by $7$ different terror attacks. We compare real-time mobile
communication patterns in the first $24$ hours following a terror attack to the
corresponding patterns on days with no terror attack. On ordinary days, the
group of female and male participants have different activity patterns.
Following a terror attack, however, we observe a significant increase of the
gender differences. Knowledge about citizens' behavior response patterns
following terror attacks may have important implications for the public
response during and after an attack.
