Effects of the 1985 Michoacan earthquake on water systems and other buried lifelines in Mexico

ABSTRACT

In this report the effects of the 1985 Michoacan Earthquake on water systems in Mexico are investigated. Because the damage from the 1985 event was most severe in Mexico city, the report concentrates on the Metropolitan Mexico City Area. A historical perspective is provided by information about seismic damage to Mexican water systems due to past earthquakes. This historical perspective highlights the seismic vulnerability of these types of systems. The effects of the earthquake on water supply as well as some aspects of the emergency response are discussed. Soil conditions in Mexico City and the characteristics of the earthquake are investigated and correlated with the observed damage. Damage statistics are presented for the buried segmented pipelines in the water system. Other sections are devoted to damage to a continuous (welded steel) pipeline and to seismic effects on the sewer and underground Metro lifelines. Seismic damage to lifelines in the epicentral region was relatively light. A comparison of ground motion characteristics recorded in Mexico City and in the epicentral region is used to explain these differences. Finally , a general summary and recommendations to reduce the seismic vulnerability of the Mexico City water system as well as other water systems are given.(AU)