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each of the Waimakariri River and along the Kaiapoi Riversustained varying levels of damage during both events. In allcases observed by the authors, damage was related to liquefactionin the foundation soils. In an attempt to relate the severityof the observed levee damage to the liquefaction response ofthe foundation soil, damage severity was correlated to factorof safety against liquefaction and to thickness of the liquefiedlayer. While damage severity correlated to both of these measures,the factor of safety against liquefaction appears to be thebetter index of damage severity when lateral spreading is theprimary failure mode.DATA AND RESOURCESPersonal communications with Tony Boyle took place 27September 2010. Personal communications with Ian Hesloptook place October and November 2010 and May and July2011.ACKNOWLEDGMENTSThe primary support for the U.S. GEER team memberswas provided by grants from the U.S. National ScienceFoundation (NSF) as part of the Geotechnical Extreme EventsReconnaissance (GEER) Association activity through CMMI-00323914 and NSF RAPID grant CMMI-1137977. Also,Dr. Wotherspoon’s position at the University of Auckland isfunded by the New Zealand Earthquake Commission (EQC).However, any opinions, findings, and conclusions or recommendationsexpressed in this material are those of the authorsand do not necessarily reflect the views of the National ScienceFoundation or the EQC.REFERENCESGriffiths, G. A. (1979). Recent sedimentation history of the WaimakaririRiver, New Zealand. Journal of Hydrology (New Zealand) 18, 6–28.Iwasaki, T., K. Tokida, F. Tatsuoka, S. Watanabe, S. Yasuda, and H. Sato(1982). Microzonation for soil liquefaction potential using simplifiedmethods. Proceedings of the Third International Conference onEarthquake Microzonation, Seattle WA, 1,319–1,330.Larned, S. T., D. M. Hicks, J. Schmidt, A. J. H. Davey, K. Dey, M.Scarsbrook, D. B. Arscott, and R. A. Woods (2008). The SelwynRiver of New Zealand: A benchmark system for alluvial plain rivers.River Research and Applications 24, 1–21.New Zealand Aerial Mapping (2010). Kaiapoi (air photo). Wellington,New Zealand.New Zealand Aerial Mapping (2011). Kaiapoi (air photo). Wellington,New Zealand.Riley Consultants (2010). Waimakariri and Kaiapoi River StopbanksPost Earthquake Condition Assessment. Report 10820-B preparedby Riley Consultants for Environment Canterbury (ECan). RileyConsultants, Christchurch, New Zealand.Riley Consultants (2011). Waimakariri and Kaiapoi River StopbanksFindings of Condition Assessment Post 22 February 2011 Earthquake.Letter Report 10820/2-A from Riley Consultants to EnvironmentCanterbury (ECan). Riley Consultants, Christchurch, NewZealand.Te Ara Encyclopedia of New Zealand (2010). http://www.teara.govt.nz/en/floods/6/7.Tonkin and Taylor (2011). Darfield Earthquake Recovery GeotechnicalFactual Report—Kaiapoi North. Report EP-KAN-FAC preparedby Tonkin and Taylor, Ltd. for the New Zealand EarthquakeCommission. Tonkin and Taylor, Christchurch, New Zealand.van Kalken, T., T. Oliver, I. Heslop, and T. Boyle (2007). Impacts ofsecondary flood embankments on the Waimakariri floodplain,New Zealand. Proceedings of the 32nd Congress of the InternationalAssociation of Hydraulic Engineering and Researchers, July 1–6,2007, Venice, Italy.Wotherspoon, L. M., M. J. Pender, and R. P. Orense (2011). Relationshipbetween observed liquefaction at Kaiapoi following the 2010Darfield earthquake and former channels of the WaimakaririRiver. Submitted to Engineering Geology.Youd, T. L., I. M. Idriss, R. D. Andrus, I. Arango, G. Castro, J. T.Christian, R. Dobry, et al. (2001). Liquefaction resistance of soils:Summary report from the 1996 NCEER and 1998 NCEER/NSFworkshops on evaluation of liquefaction resistance of soils. ASCEJournal of Geotechnical & Geoenvironmental Engineering 127 (10),817–833.Department of Civil and Environmental EngineeringVirginia Tech120B Patton HallBlacksburg, Virginia 24061 U.S.A.rugreen@vt.edu(R. A. G.)Seismological Research Letters Volume 82, Number 6 November/December 2011 949