The application of seismic risk-benefit analysis to land use planning in Taipei City

In the developing countries of Asia local authorities rarely use risk analysis instruments as a decision-making support mechanism during planning and development procedures. The main purpose of this paper is to provide a methodology to enable planners to undertake such analyses. We illustrate a case study of seismic risk-benefit analysis for the city of Taipei, Taiwan, using available land use maps and surveys as well as a new tool developed by the National Science Council in Taiwan--the HAZ-Taiwan earthquake loss estimation system. We use three hypothetical earthquakes to estimate casualties and total and annualised direct economic losses, and to show their spatial distribution. We also characterise the distribution of vulnerability over the study area using cluster analysis. A risk-benefit ratio is calculated to express the levels of seismic risk attached to alternative land use plans. This paper suggests ways to perform earthquake risk evaluations and the authors intend to assist city planners to evaluate the appropriateness of their planning decisions.