Social implosion

In sociology, a social impolosion refers to an event where a subgroup of a larger group suddenly becomes separated from the larger group -- the members of the subgroup sever their connections to the larger group (often society as a whole), and their entire social lives become involved in the smaller group. Generally cults (in the sociological sense) are formed by social implosions; although many such social implosions are short-lived, only a small minority lasting long enough to become a cult.