  The proliferation of terrorism is a serious concern in national and
international security, as its spread is seen as an existential threat to
Western liberal democracies. Understanding and effectively modelling the spread
of terrorism provides useful insight into formulating effective responses. A
mathematical model capturing the theoretical constructs of contagion and
diffusion is constructed for explaining the spread of terrorist activity and
used to analyse data from the Global Terrorism Database from 2000--2016 for
Afghanistan, Iraq, and Israel.
