The Mexico Earthquake of September 19,1985—An Analysis of the Insured Loss and Implications for Risk Assessment

Abstract

This study is organized in three parts. Part 1 presents the results of a statistical evaluation of insured losses caused by the Mexican earthquake and discusses them with respect to their universal validity. Identified as the most heavily affected risk categories are: medium - and high-rise buildings, state housing schemes (Tlatelolco), commercial risks and business interruption. The vulnerability of contents is found to depend heavily on the type of risk affected and on the local intensity. Part 2 isolates the multiple factors of seismological, geotechnical and risk-specific nature which contributed to the damage pattern generated by the Mexican earthquake. Finally, in part 3 the experience of the Mexican earthquake and other recent earthquakes is combined to enter into a general discussion on loss ratios and insurance tariffs, on the global threat of long-period effects and on implications for the assessment of catastrophe potential. In particular the problem of regionally representative MMI degrees is addressed in view of the relatively low loss ratios observed, which did not exceed 10% in Zone C or 5% in the coastal area.