Including Earthquake Risk Perception in Risk Reduction Modeling

Resistance to investing in earthquake hazard mitigation, such as strengthening or replacing existing buildings and facilities, is common in both Japan and the U.S. The challenge is to find effective ways to change values and processes so loss prevention becomes an important organizational and community goal that results in decision-makers giving higher priority and greater resources to mitigation.

Researchers in both the U.S. and Japan are developing methodologies for Performance-Based Earthquake Engineering (PBEE), a relatively new concept that facilitates the design of structures and systems for specific earthquake performance levels. However, the more rigorous PBEE formulation for the "engineering benefit" is only one of the inputs to the decision process for specific mitigation action. Other inputs to the decision process come from the social, economic, and political issues that affect those making the decision. Therefore, a multidisciplinary approach is needed to understand mitigation actions and therefore overall risk reduction.

Our work focused on defining the decision process of key decision-makers in responsible and authoritative positions in moderate to large private companies (the "unit of analysis"). Their decisions include investing in earthquake loss prevention strategies and technologies as part of new construction or retrofitting/rehabilitation projects. We then propose a more generalized framework for a "Community Earthquake Risk Reduction Model (CERRM)," based upon the multiple and varied inputs to decision and action. The CERRM could provide a framework for the evaluation of the relative effects of different engineering, social, economic, or political actions on the earthquake risk of a community.