An Investigation of the Geotechnical Aspects of the June 1999 Central Mexico Earthquakes - Preliminary Assessment

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

Abstract 9985983 The central region of Mexico experienced strong earthquakes on 15 June (Moment magnitude 7.0) and 21 June 1999 (M = 6.3). The first earthquake resulted in 15 fatalities. There were no deaths resulting from the second earthquake; however thousands of buildings were damaged, some severely. The most notable effects occurred in unreinforced masonry (URM) structures, such as churches and small adobe and cane houses. Site effects were possibly important in some of the cases. A number of strong motion instruments recorded the ground motions in the affected area. A research team of graduate students and faculty from the University of California at Berkeley (UC ) and the National Autonomous University of Mexico (UNAM), made a post-earthquake preliminary field investigation of seismic geotechnical issues, sponsored by the Pacific Earthquake Engineering Research Center (PEER). This action is to support the publication of a report on the key geotechnical aspects of these earthquakes. This report is being made available in hard copy and via the World Wide Web, in order to disseminate the key lessons learned. This action follows similar work that was supported following the 1985 Mexico earthquake, and is complementary to the support being provided to assist in the maintenance and distribution of data from the Guerrero strong motion array along the west coast of Mexico. As with all post-earthquake reconnaissance investigations, it is expected that vital records and data will become available as a result of these recent earthquakes in Mexico. From a scientific viewpoint, these large earthquakes act as full scale experiments that cannot be duplicated via controlled experiments in the laboratory or in the field. It is through quick response reconnaissance efforts that the mostly-ephemeral data from these events can be recovered and used to further advances in earthquake hazard mitigation.