CEE Seminar: Silty Soil Liquefaction Effects in Christchurch, New Zealand

Abstract: Liquefaction damage from the 2010-11 Canterbury earthquake sequence devastated over 30% of the built environment in Christchurch, New Zealand. State-of-practice liquefaction assessment procedures have been shown to work generally well across much of Christchurch, when compared with post-earthquake damage observations. However, there are important case history sites where the state-of-practice liquefaction assessment procedures indicate that significant liquefaction-induced ground failure would be expected to occur, but no surface manifestations of liquefaction were observed during post-earthquake reconnaissance. These sites are located predominantly in the southwest part of the city, an area known among local engineers for its silty soil conditions. This presentation will explore investigations of the apparent discrepancy between state-of-practice liquefaction estimations and post-earthquake liquefaction observations at silty soil sites in southwest Christchurch. The issues highlighted in this presentation will demonstrate the need for a more holistic approach to liquefaction assessment and consideration of system response at silty soil sites, with a focus on liquefaction manifestations.

Bio: Christine Z. Beyzaei is a senior engineer in the civil engineering practice at Exponent, Inc. in Oakland, California.  She received her B.S. degree from George Washington University and her M.S. and Ph.D. degrees from UC Berkeley.  Christine specializes in geotechnical earthquake engineering, performing research and post-earthquake reconnaissance in the U.S. and internationally. She is active in the Earthquake Engineering Research Institute (EERI), American Society of Civil Engineers (ASCE) and the Geotechnical Extreme Events Reconnaissance Association (GEER). She received the 2016-17 EERI/FEMA-NEHRP Graduate Fellowship in Earthquake Hazard Reduction and was selected as a 2020 Visiting Professional for the EERI Friedman Family Visiting Professionals Program.