The adoption and enforcement of seismic provisions in modern building codes is a critical step toward becoming better prepared for an earthquake. Despite the incredible magnitude of the Chilean quake, the devastation would have been many times worse--perhaps on the scale of Haiti--had the country not long ago adopted and begun enforcing stringent building codes. Building codes provide minimum acceptable standards used to regulate design, construction and maintenance of buildings to protect the health, safety and general welfare of the building's users.

(See an article, "Scant insurance coverage to hurt Haiti rebuilding.")

The International Code Council (ICC) has developed the most widely adopted set of codes. Although the ICC code has been updated several times during the past decade, the seismic provisions have remained relatively unchanged since 2000. Mandatory application and enforcement of these codes and adoption of local amendments, which affect the building code regulatory process and the protections it provides, vary by state.

What follows are both regional and state-by-state analyses of the state of building codes in jurisdictions sitting atop major fault zones in the U.S.

Charleston, S.C. follows the 2006 edition of the International Codes and has made no amendments to the seismic provisions, which are considered adequate protections. The state first adopted a statewide code and mandatory enforcement in July 2003, which equates to a limited inventory of code compliant structures. The latest hazard maps have been revised to include offshore faults that may be capable of generating earthquakes, which may increase the chances of an earthquake in the Charleston area.

The Pacific West Coast includes California, Oregon and Washington. All three states have mandatory statewide building codes in place in accordance with the 2006 version of the International Codes. Each of the states has passed amendments that exceed the ICC codes to make the seismic requirements more stringent. The building standards in place in this region of the country are more reflective of the latest and best available science.

The New Madrid Zone/Wabash Valley was the site of three major earthquakes and a series of aftershocks from 1811-1812, which are considered the most intense inter-plate earthquakes to have occurred in recorded U.S. history. This fault zone crosses the states of Arkansas, Illinois, Indiana, Kentucky, Mississippi, Missouri, and Tennessee. Several states in the region do not have adequate code coverage and/or code enforcement in place. This is despite agreement among most scientists that there is a 90 percent probability of an earthquake of a magnitude between 6 and 7 occurring in this region in the next 50 years, according to the U.S. Geological Survey.

State-by-state analysis

Arkansas adopted a statewide building code, but its use is not mandatory. Power is given to individual jurisdictions to adopt and enforce the code. If a jurisdiction chooses to move forward with code adoption and enforcement, it must do so in accordance with the state-approved code (in this case, the 2006 International Codes). The state allows for local modifications for more stringent, but not weaker, amendments.

Illinois and Missouri have no statewide mandatory code in place, although some local jurisdictions such as Chicago and St. Louis have adopted and enforce citywide building codes. The seismic provisions of these local codes vary, along with the requirements for mandatory enforcement.

Indiana has a mandatory statewide code based on the 2006 version of the International Code and requires mandatory enforcement. However, the Indiana Department of Homeland Security has stated that some jurisdictions lack building inspection departments and therefore the code is not being enforced, despite the requirements. The state allows for local modification for more stringent, but not weaker, amendments.

Mississippi adopted the 2003 version of the International Code, but local jurisdictions have the power to adopt and enforce it and to decide on seismic provisions. If a jurisdiction in Mississippi chooses to adopt and enforce a code, it must be consistent with the code adopted by the state.

Tennessee adopted the 2006 version of the International Code, but some areas of the state are exempt.

The Institute for Business and Home Safety (IBHS) offers a variety of earthquake property loss prevention projects for the interior and exterior of homes and businesses, including a complete retrofit guide in English and Spanish and a guide to the Top 10 Structural Retrofits. This material is free and available on the IBHS web site at www.DisasterSafety.org.