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Research papers, University of Canterbury Library

The 2010–2011 Canterbury earthquake sequence began with the 4 September 2010, Mw7.1 Darfield earthquake and includes up to ten events that induced liquefaction. Most notably, widespread liquefaction was induced by the Darfield and Mw6.2 Christchurch earthquakes. The combination of well-documented liquefaction response during multiple events, densely recorded ground motions for the events, and detailed subsurface characterization provides an unprecedented opportunity to add well-documented case histories to the liquefaction database. This paper presents and applies 50 high-quality cone penetration test (CPT) liquefaction case histories to evaluate three commonly used, deterministic, CPT-based simplified liquefaction evaluation procedures. While all the procedures predicted the majority of the cases correctly, the procedure proposed by Idriss and Boulanger (2008) results in the lowest error index for the case histories analyzed, thus indicating better predictions of the observed liquefaction response.

Articles, UC QuakeStudies

A document outlining the Emergency Management Policy at the University of Canterbury in the time between the 4 September 2010 and 22 February 2011 earthquake. This policy was developed to provide a mandate for decisions that need to be taken to most appropriately and expeditiously respond to a planned event or unforeseen critical incident at the University of Canterbury.

Images, Alexander Turnbull Library

Scientists stand before a model that will predict earthquakes. The model is a large arm attached to wires and switches with a thumb that flicks coins '"Heads" we have big quake at five-o-clock... "tails" we don't'. Context: short term predictions (hours to days) are in general unlikely to be possible, at present. Relates to the Christchurch earthquakes which experts have said could go on for years. Quantity: 1 digital cartoon(s).

Images, Alexander Turnbull Library

The cartoon shows the word 'Christchurch' fractured by earthquake. Text above reads 'The new tear(s)'. A second version has the text in the singular 'The new tear'. Context: In spite of Christchurch's great hopes for a new year without earthquakes, there have been numerous quakes and aftershocks. A wordplay on 'new year' and 'new tear' - that is weeping with fear and dismay. Two versions of this cartoon are available Quantity: 2 digital cartoon(s).

Research Papers, Lincoln University

Liquefaction features and the geologic environment in which they formed were carefully studied at two sites near Lincoln in southwest Christchurch. We undertook geomorphic mapping, excavated trenches, and obtained hand cores in areas with surficial evidence for liquefaction and areas where no surficial evidence for liquefaction was present at two sites (Hardwick and Marchand). The liquefaction features identified include (1) sand blows (singular and aligned along linear fissures), (2) blisters or injections of subhorizontal dikes into the topsoil, (3) dikes related to the blows and blisters, and (4) a collapse structure. The spatial distribution of these surface liquefaction features correlates strongly with the ridges of scroll bars in meander settings. In addition, we discovered paleoliquefaction features, including several dikes and a sand blow, in excavations at the sites of modern liquefaction. The paleoliquefaction event at the Hardwick site is dated at A.D. 908-1336, and the one at the Marchand site is dated at A.D. 1017-1840 (95% confidence intervals of probability density functions obtained by Bayesian analysis). If both events are the same, given proximity of the sites, the time of the event is A.D. 1019-1337. If they are not, the one at the Marchand site could have been much younger. Taking into account a preliminary liquefaction-triggering threshold of equivalent peak ground acceleration for an Mw 7.5 event (PGA7:5) of 0:07g, existing magnitude-bounded relations for paleoliquefaction, and the timing of the paleoearthquakes and the potential PGA7:5 estimated for regional faults, we propose that the Porters Pass fault, Alpine fault, or the subduction zone faults are the most likely sources that could have triggered liquefaction at the study sites. There are other nearby regional faults that may have been the source, but there is no paleoseismic data with which to make the temporal link.