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Images, eqnz.chch.2010

Friday 22 February 2013. Official Supported Site for River of Flowers: Horseshoe Lake Riverbank on Lake Terrace Road, opposite the bus stop between Oregon and Tangmere Places Hosted by: Burwood Primary School and Community. File reference: CCL-2013-02-22-River-of-FlowersDSC_03401.JPG From the collection of Christchurch City Libraries. ...

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.

Images, UC QuakeStudies

A photograph of the damaged Provincial Council Chambers on Durham Street. The building's roof and walls have collapsed, as has the scaffolding which was erected to repair it after the 4 September 2010 earthquake.

Images, UC QuakeStudies

A photograph of two workers walking down Gloucester Street. To the right, the earthquake-damaged Canterbury Times and Star Building can be seen. A car parked in front has been crushed by falling debris.

Images, UC QuakeStudies

Members of the public in Cranmer Square, the meeting point for many businesses after the 22 February 2011 earthquake. Two people at the front of the photo are wearing dressing gowns and wheeling luggage.

Images, UC QuakeStudies

Members of the USAID Disaster Assistance Response Team (DART) photographed with their team leader, Al Dwyer, Prime Minister John Key, and Canterbury Earthquake Recovery Minister Gerry Brownlee, outside the US headquarters in Latimer Square.

Images, UC QuakeStudies

Members of the USAID Disaster Assistance Response Team (DART) and the New Zealand Urban Search and Rescue, breaking through the floor of a building which was severely damaged during the 22 February 2011 earthquake.