(a) “Civil emergency” is defined as:

(1) A riot or unlawful assembly characterized by any use of force or violence disturbing the public peace, or any threat to use such force and violence, if accompanied by immediate power of execution, by two (2) or more persons acting together and without authority of law.

(2) Any natural disaster or man-made calamity, including but not limited to flood, conflagration, cyclone, tornado, earthquake or explosion within the geographic limits of a municipality resulting in the death or injury of persons, or the destruction of property to such an extent that extraordinary measures must be taken to protect the public health, safety and welfare.

(3) The destruction of property, or the death or injury of persons brought about by the deliberate acts of one (1) or more persons acting either alone or in concert with others when such acts are a threat to the peace of the general public or any segment thereof.

(b) “Curfew” is hereby defined as a prohibition against any person or persons walking, running, loitering, standing, sitting, lying or motoring upon any alley, street, public property or vacant premises within the corporate limits of the municipality except persons officially designated to duty with reference to said civil emergency or those lawfully on the streets as defined hereinafter.

(c) “Chief administrative officer” is defined to be the mayor of any municipality. Any municipality, however, may by ordinance specially designate any official as chief administrative officer for purposes of this chapter.