An unfounded anxiety shared by people who can be scattered over a wide geographic area. revolutionary movement moral panic mass hysteria mob propaganda rumor collectivity

An unfounded anxiety shared by people who can be scattered over a wide geographic area is called "Mass Hysteria".

Explanation:

Mass hysteria is the sociopsychological phenomenon that comprises the manifestation of the same or similar hysterical symptoms by more than one person.

A common manifestation of mass hysteria occurs when a group of people believe they are suffering from a similar illness or ailment. Thus, the group usually shows enthusiasm or anxiety, irrational behavior or unexplained symptoms of some disease.