The Housing Slump

Images, UC QuakeStudies

Two images of a house, taken before and after the earthquakes. In the after photograph the chimneys are gone, a column supporting the car port has partly collapsed, windows are broken, and the previously neat lawn and driveway are overgrown. The photographer comments, "This was a house that I was selling up to the September 2010 earthquake in Christchurch. It was on Avonside Drive, which was an area that has been badly hit in every earthquake that has hit the area. In the September quake parts of the house moved in different directions and one of the upstairs doors had to be smashed open to release one of the sons from his bedroom. This occurred in the dark with numerous aftershocks shaking the house. Liquefaction poured up through the floor and flowed down the drive. Everyone got out OK, but soon after the house was red stickered meaning it was dangerous to enter. The house was looted many times even though there was constant police patrols. When the most violent earthquake occurred on 22 February 2012 both the tall heavy chimneys came crashing through into the living areas. Subsequent earthquakes and aftershocks have caused one of the brick fence pillars to fall and the front garage pillar to break up and twist. The family's troubles did not end there. They moved into the home of one of their parents and this mansion of a home was so badly affected by the February earthquake that no one could enter to collect any of their or their parents' belongings. They now own a new home, which they are fond of except when the ground shakes yet again. There has been to date 10,712 earthquakes and aftershocks since 4 September 2010".

Geotechnical Aspects of the 22 February 2011 Christchurch earthquake

Research papers, University of Canterbury Library

The 22 February 2011, Mw6.2-6.3 Christchurch earthquake is the most costly earthquake to affect New Zealand, causing 181 fatalities and severely damaging thousands of residential and commercial buildings, and most of the city lifelines and infrastructure. This manuscript presents an overview of observed geotechnical aspects of this earthquake as well as some of the completed and on-going research investigations. A unique aspect, which is particularly emphasized, is the severity and spatial extent of liquefaction occurring in native soils. Overall, both the spatial extent and severity of liquefaction in the city was greater than in the preceding 4th September 2010 Darfield earthquake, including numerous areas that liquefied in both events. Liquefaction and lateral spreading, variable over both large and short spatial scales, affected commercial structures in the Central Business District (CBD) in a variety of ways including: total and differential settlements and tilting; punching settlements of structures with shallow foundations; differential movements of components of complex structures; and interaction of adjacent structures via common foundation soils. Liquefaction was most severe in residential areas located to the east of the CBD as a result of stronger ground shaking due to the proximity to the causative fault, a high water table approximately 1m from the surface, and soils with composition and states of high susceptibility and potential for liquefaction. Total and differential settlements, and lateral movements, due to liquefaction and lateral spreading is estimated to have severely compromised 15,000 residential structures, the majority of which otherwise sustained only minor to moderate damage directly due to inertial loading from ground shaking. Liquefaction also had a profound effect on lifelines and other infrastructure, particularly bridge structures, and underground services. Minor damage was also observed at flood stop banks to the north of the city, which were more severely impacted in the 4th September 2010 Darfield earthquake. Due to the large high-frequency ground motion in the Port hills numerous rock falls and landslides also occurred, resulting in several fatalities and rendering some residential areas uninhabitable.

Question Time for 16 June 2011

Audio, Radio New Zealand

Questions to Ministers 1. Hon DAVID PARKER to the Minister of Finance: What was the combined increase in the value of the Crown's equity in Meridian, Mighty River Power, Solid Energy, Genesis and Air New Zealand for each of the last five years? 2. SIMON BRIDGES to the Minister of Finance: How did Budget 2011 continue the Government's programme to build faster growth, higher incomes and more jobs? 3. Hon MARYAN STREET to the Minister of Foreign Affairs: Have all recent actions of New Zealand's diplomats been consistent with Government policy? 4. Hon TAU HENARE to the Minister of Health: What reports has he received about improved access to dialysis for patients in Auckland and Waitemata? 5. Dr RUSSEL NORMAN to the Minister of Finance: Will the Government have to borrow further to pay for the latest Christchurch earthquakes? 6. GRANT ROBERTSON to the Minister of Health: Does he agree with the statement of the Auditor-General, "Despite the encouraging improvements made in the last 10 years, we do not yet have a system for scheduled services that can demonstrate national consistency and equitable treatment for all"? 7. AMY ADAMS to the Minister for the Environment: What steps has the Government taken to facilitate resource consents for work required at the Lyttelton Port to ensure it is able to recover quickly from earthquake damage? 8. JACINDA ARDERN to the Prime Minister: Does he stand by the statement made on his behalf that "this Government is focused on improvements within the economy in order to create the platform on which business and New Zealanders can invest and grow jobs"? 9. TE URUROA FLAVELL to the Minister of Health: Does he agree that under section 118 of the Health Practitioners Competence Assurance Act 2003, the Medical Council has a responsibility to ensure the cultural competence of doctors, and what support has the Government provided to the health sector to ensure cultural competence is achieved across the health sector? 10. DAVID SHEARER to the Minister of Science and Innovation: Does he agree with Professor Sir Paul Callaghan's statement on science and innovation "it's clear that the Minister of Finance and the Prime Minister have not really seen this as a top priority"? 11. CHESTER BORROWS to the Minister of Justice: What progress is being made on preparations for the referendum on the electoral system to be held in conjunction with this year's general election? 12. Hon RICK BARKER to the Minister of Veterans' Affairs: When can veterans expect to have a full response from the Government in response to the Law Commission's report "A New Support Scheme for Veterans"?