The 2015 New Zealand strong-motion database provides a wealth of new strong motion data for engineering applications. An important component of this database is the compilation of new site metadata, describing the soil conditions and site response at GeoNet strong motion stations. We have assessed and compiled four key site parameters for the ~460 GeoNet stations that recorded significant historical ground motions. Parameters include: site classification (NZS1170.5), Vs30, fundamental site period (Tsite) and depth to bedrock (Z1.0, i.e. depth to material with Vs > 1000 m/s). In addition, we have assigned a quality estimate (Quality 1 – 3) to these parameters to provide a qualitative estimate of the uncertainty. New highquality Tsite estimates have largely been obtained from newly available HVSR amplification curves and spectral ratios from inversion of regional strong motion data that has been reconciled with available geological information. Good quality Vs30 estimates, typically in urban centres, have also been incorporated following recent studies. Where site-specific measurements of Vs30 are not available, Vs30 is estimated based on surface geology following national Vs30 maps. New Z1.0 values have been provided from 3D subsurface models for Canterbury and Wellington. This database will be used in efforts to guide development and testing of new and existing ground motion prediction models in New Zealand. In particular, it will allow reexamination of the most important site parameters that control and predict site response in a New Zealand setting. Furthermore, it can be used to provide information about suitable rock reference sites for seismological research, and as a guide to site-specific references in the literature. We discuss compilation of the database, preliminary insights so far, and future directions.
Christchurch's earthquake rebuild authority, Regenerate Christchurch, has released a new report setting out a timeline for what to do with the land - but angry residents are calling for action.
Here in New Zealand, we like to think ourselves as a nation of outdoor enthusiasts, always off tramping, kayaking, mountain biking, etc. But it wasn’t always thus. Our love affair with the outdoors began in the mid-late 19th century and was … Continue reading →
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.
Since the 7.8 magnitude earthquake jolted North Canterbury on Monday, the HMNZS Canterbury has evacuated about 640 people, 9.3 tonnes of baggage, a cat, 17 dogs. And, about 30,000 bees. But South Island beekeepers will face ongoing challenges. John Hartnell, is a Canterbury-based board member of Apiculture New Zealand.
Purpose - The purpose of this paper is to identify through the application of Actor Network Theory (ANT) the issues and impediments to the implementation of mandatory seismic retrofitting policies proposed by the New Zealand Government. In particular the tension between the heritage protection objectives contained in the Resource Management Act 1991 and the earthquake mitigation measures contained in the Building Act 2004 are examined. Design/methodology/approach - The paper uses a case study approach based on the Harcourts Building in Wellington New Zealand and the case law relating to attempts to demolish this particular building. Use is made of ANT as a 'lens' to identify and study the controversies around mandatory seismic retrofitting of heritage buildings. The concept of translation is used to draw network diagrams.
A review of the week's news including... An immigration lawyer says 'paying for jobs' is so rampant in New Zealand there needs to be a fresh look at powers available to officials, criminals are using sex to blackmail Indian male students, Auckland lays out its plan to spend 83 billion dollars on transport, the electrified section of the main trunk line between Auckland and Wellington could be mothballed, frustrated advocates are calling for better reporting of suicides committed by current and former members of the military, doctors say making voluntary euthanasia legal would involve many complex and difficult decisions and New Zealand should avoid it, the Morning Report Wellington mayoral candidates debate, a Maori fisheries body wants the Maori Party to abandon its support for the Government if plans for a Kermadec ocean sanctuary go ahead unchanged, Maori representation becomes a virtual no-go area for those vying for public office in New Plymouth, Colin Craig denies ever sending his former press secretary explicit text messages, the United Nations Committee on the Rights of the Child raises concerns about the naming of the new children's ministry, MPs hear emotional pleas from the family of soldiers killed in action and buried in Malaysia for the government to bring their remains home, Bruce Springsteen and the E Street Band will perform in Christchurch on the eve of the sixth anniversary of the Canterbury earthquakes this summer and Prince Charles praises New Zealand soldiers who fought at the Somme at a centennary ceremony in Northern France.
Belinda McCammon tracks progress in Christchurch 5 years after the earthquake that killed 185 people
Frustrated Christchurch home-owners have delivered a 3000 strong petition to the government, calling for a Royal Commission of Inquiry into shoddy earthquake repairs.
After calls for an inquiry into Christchurch home repairs, Canterbury Earthquake Recovery Minister Gerry Brownlee joins Checkpoint.
A decision on the future of Christchurch's red zoned land could be made within a year. That's the hope of the man at the helm of Regenerate Christchurch, one of two organisations charged with taking over the city's rebuild from the Earthquake Recovery Authority, which shuts its doors in just three days.
What's being called a landmark settlement with the Earthquake Commission has been reached today, which may have far-reaching consequences for Canterbury home-owners.
When the Canterbury earthquakes brought about the destruction of almost all of the buildings in central Christchurch, it created a unique opportunity for an insight into the past.
Christchurch's leading business group is criticising city council plans to slow down its earthquake rebuild programme. Conan Young reports.
After being largely shut off to the public since the earthquakes, Christchurch's iconic Arts Centre is set to reopen its Great Hall to the public tonight.
Worries about the mental health impacts of the Canterbury earthquakes dominated a fiery meeting at Parliament today.
Christchurch council has asked its residents to tell it if earthquake repairs haven't been done so it can accurately assess their property's value.
Karen Brown reports from Chch, where there seems to be no end in sight for the mental health problems caused by the earthquakes
An investigation is continuing into the CTV site, where 115 people died in the Christchurch earthquake five years ago. Dr Maan Alkaisi, whose wife died in the collapse, is keeping a close eye on developments as engineers examine the site.
A world class centre for music and the arts has opened in Christchurch, after The Music Centre of Christchurch was damaged beyond repair in the 2011 earthquakes.
The agency in charge of fixing earthquake damaged pipes and roads in Christchurch was last night issued an excessive noise notice after keeping residents awake in the early hours.
The number of emergency psychiatric assessments in Christchurch has more than doubled since the earthquakes struck.
Christchurch's tourism sector is poised for a strong rebound five years after the Canterbury earthquakes, but tourist operators and leaders say there is still work to do.
A backpackers with pod-styled units has opened near Christchurch Airport as the city continues to struggle with budget accommodation following the 2011 earthquake.
Repair work on Christchurch's iconic Town Hall, badly damaged in the earthquakes, has nearly hit the halfway mark.
A class action taken by 40 Canterbury earthquake claimants against Southern Response heads to court tomorrow.
Forty Christchurch homeowners have headed back to court, as they seek to take a class action against earthquake insurer Southern Response.
Those repairing an earthquake damaged cliff in Christchurch have had to wrangle with home owners who don't want to sell, and relocating a rare flightless moth. Rachel Graham reports.
The orange road cone has become a symbol of Christchurch since the earthquakes. Now two men and a trailer have the job of retrieving the hundreds of cones that have gone missing over the past six years.
Christchurch Mayor Lianne Dalziel has experienced her fair share of earthquakes as a resident, MP and then Mayor. She joins Checkpoint.