1. Notwithstanding other provisions of law to the contrary, the state geologist and the U. S. Geological Survey shall notify the state emergency management agency of each city, town, village or county of this state which can be expected to experience an intensity of ground shaking equivalent to a Modified Mercalli of VII or above from an earthquake occurring along the New Madrid Fault with a potential magnitude of 7.6 on the Richter Scale, shall adopt an ordinance or order requiring that new construction, additions and alterations, as such term is defined by either the uniform building code or building officials and code administrators code, to existing buildings and structures within the city, town, village or county comply with the standards for seismic design and construction of the building officials and code administrators code or of the uniform building code. Each city, town, village or county required to adopt seismic design and construction provisions pursuant to this subsection shall adopt an ordinance or order requiring that new construction, additions and alterations, as such term is defined by either the uniform building code or building officials and code administrators code, comply with the standards for seismic design and construction of the 1990 or later edition of either the uniform building code or the building officials and code administrators code.

2. In no event shall sections 319.200 to 319.207 nor any ordinances or orders adopted by any city, town, village or county of this state be construed to mandate that existing buildings, by reason of any proposed addition or alteration, be further modified or reconstructed so as to comply with the current code relevant to seismic considerations. Seismic design criteria as to additions and alterations apply only to structural components constituting the addition or alteration and shall not be applied to require reconstruction or fortification of existing structures proposed to be altered. If any addition or alteration adversely affects portions of existing facilities which are not being altered, then those parts thus affected may require evaluation and possible reinforcement such that the additions or alterations will result in a structure that is at least as safe as it was prior to the additions or alterations.