Reconnaissance of the Geotechnical Aspects of the February 28, 2001 Nisqually Earthquake

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

This action is to support a study to complete the post-earthquake reconnaissance effort begun the day after the February 28, 2001 Nisqually Earthquake, and to further document observations of important cases of ground failure and building damage from this event. Well-documented case histories of building performance at sites undergoing severe and minor ground failure will be developed through selected field and laboratory testing. These case histories will be documented at the website developed during the post-earthquake reconnaissance of the Nisqually earthquake, and in a paper to be published in the Journal "Spectra" of the Earthquake Engineering Research Institute (EERI). Timely reporting of these results will enable researchers to incorporate these data into ongoing studies and identify additional work resulting from this important Pacific Northwest earthquake. Professor Bray and some of his colleagues and graduate student researchers traveled immediately to the affected area of the Nisqually earthquake, and as part of a larger reconnaissance team completed documentation of some of the more important geotechnical aspects of this event. This included conducting detailed surveys of ground deformation from a significant lateral spread involving the Deschutes Parkway, mapping of ground deformation at the Martin Way embankment failure, documentation and sampling of sediment ejecta in several building foundations in South Seattle, and surveying of the Highway 101 embankment failure. The goals of this follow-up study will be met in part by completing documentation of these important case records, with emphasis on the Deschutes Parkway in Olympia and the building foundations performance in South Seattle. Stephen P. Palmer, Washington State Department of Natural Resources, assisted during the post-earthquake reconnaissance effort and who will be involved in this current project.