The Legislature finds and declares that the impact of the Mexico City earthquake disaster of September 19, 1985, has rendered more cogent and compelling the findings of the Legislature set forth in Section 8870, particularly subdivision (c) thereof, and heightened the need for authority for local agencies to engage in effective preevent and postevent activity to accomplish those goals set forth in paragraph (4) of subdivision (b) of Section 8872. It is the intent of this chapter to provide that authority.