Need cited for cordon flexibility
POLICY makers should consider flexibility to meet human needs, including retrieving pets and memorabilia, when planning postearthquake cordons, Otago researchers say.
University of Otago Centre for Sustainability deputy director Caroline Orchiston is the lead author of a paper released this week by researchers examining the impacts of postearthquake cordons.
Policy makers should plan to minimise negative outcomes, including disruption to business and home life, when businesses and homes were placed behind a cordon, she said.
The paper examines the impacts of such cordons, using data collected after the 6.3 magnitude Christchurch quake in 2011, and the 6.3 magnitude L’Aquila, Italy, quake in 2009.
Yesterday marked 10 years since the 7.2 magnitude Darfield earthquake, centred 40km west of Christchurch, which significantly damaged central Christchurch, resulting in cordons to restrict access.
Cordons were ‘‘a necessary and very useful disaster management tool’’, which could help a city and its people recover from a major quake.
However, after the immediate physical threat had passed, and if damaged buildings were safe to enter, cordon managers might wish to ‘‘provide flexibility in cordon access’’.
Such flexibility may encourage residents to evacuate quickly after a quake, rather than spend time gathering valuables before leaving.
Postearthquake cordons could also result in the psychological effect of loss of/stranding of pets, and adverse impacts on physical, mental and emotional health.
The researchers wanted to address a gap in academic literature on the societal implications of such cordons, including effects on housing, social welfare and health, she said.
People should also consider preparing an emergency ‘‘go bag’’, including family medication and some family memorabilia, which could be removed quickly.
The past decade since the Darfield earthquake on September 4, 2010, has seen incredible advances in natural hazard science and engineering. The Earthquake Commission has been a driving force behind much of this research. Its chief resilience and research officer Dr Jo Horrocks reflects on the scientific breakthroughs that have been achieved since that historic day in 2010.
LITTLE did we know on September 4, 2010, that the 7.1 Darfield earthquake was the announcement of a decade of the most destructive seismic activity that New Zealand has seen for more than 75 years.
The September 4 event was followed by the devastating 6.2 earthquake in Christchurch on February 22, 2011, as well as other tremors above magnitude 6 in Cook Strait, Lake Grassmere, Eketahuna, the East Cape and the 7.8 Kaikoura earthquake in 2016. New Zealanders have also experienced many more smaller earthquakes over the decade, and even Aucklanders have felt the earth shaking in the past week.
What we have also seen during this time is New
Zealand scientists and engineers responding to these earthquakes with innovations in techniques and advances in science, driven by a vision to reduce the harm to people and communities and wherever possible, reduce risk for the future.
A short overview commissioned by the Earthquake Commission (EQC) was published yesterday, looking at highlights of new knowledge we have collectively gained over this decade.
It shows that we have come a long way in understanding the land we live on.
The GeoNet network, which delivers data on earthquakes, volcanic activity, large landslips and tsunamis has been made denser, delivering streams of data that are critical to natural hazards science in New Zealand. All of us now also have access to what’s going on through the GeoNet website and phone app that give near instant information on when, where and how strong an earthquake or other event is.
We’ve seen big advances in how this data is used to generate computer models of what might happen in the future. This was hugely important after the Kaikoura earthquake where people living in the area, and crews working on and near any of the 11,000 landslips created by the quake, needed the best information they could possibly get on the likelihood of aftershocks.
201020 was also the decade where extensive mapping, research and cooperation among scientists showed that our largest faults, the Alpine Fault and Hikurangi Subduction Zone are primed for release. Precisely when this will happen, of course, remains the big question.
Throughout the decade New Zealand scientists and engineers also worked hard to deliver solutions for some of the biggest problems.
The liquefaction in Christchurch was unprecedented in an urban centre. It was amazing how quickly a huge team of scientists and engineers gathered and developed and tested affordable ways of strengthening liquefactionprone land so that it could be built on again, but in a way that is resilient for the future.
As well as new techniques, the work led to regulatory guidance and training courses for urban planners and engineers working in areas where land is susceptible to liquefaction.
An immensely important area of research and progress has been in engineering standards and practice for buildings. Although most buildings performed well in the different earthquakes, some did not, and with devastating consequences.
Along with a detailed understanding of why some buildings failed, over the last decade new techniques to reduce damage have been incorporated into buildings new and old. Base isolation and other technologies to damp the effects of strong shaking have been adopted, together with methods used to strengthen unreinforced masonry buildings. These include seismic gaps to allow movement, plywood diaphragms, concrete ring beams, and glassreinforced polymer to strengthen brickwork. We also now have fresh guidance for improved safety in nonstructural elements in buildings such as suspended ceilings, ducting, pipes and electrical equipment which caused much of the damage in large buildings.
Many homeowners have also been part of the action, removing brick chimneys and ensuring their houses are well secured to good foundations.
Although we now have a decade of science answers, being science, we also have a decade of new questions.
One of the big questions thrown into prominence by the Kaikoura earthquake was what slow slip events — or ‘‘silent earthquakes’’, where the tectonic forces are released over a much longer period of time — could mean for future major earthquakes. Advances in measurement using satellite technology linked to land survey data in GeoNet meant that scientists could see that the Kaikoura quake generated the most widespread triggering of slowslip events following a crustal earthquake anywhere in the world. This poses important questions about how this relates to the Hikurangi subduction zone — one of our biggest natural hazards.
I’m very proud that the EQC has been an active supporter of many of these projects. Over the past 10 years, we have invested more than $130 million in funding for GeoNet and natural hazards science and engineering research projects.
The EQC’s mission is to reduce the impact on people and property when natural disasters occur. Supporting scientific evidence to help decisionmakers in homes, communities, towns and cities reduce risk and build resilience is a big part of how we do that.
As I will tell anyone I meet, there is so much we can do before an earthquake or other hazard to reduce the chance of serious impact on people and property — and we are looking forward to continuing to play a part in making that happen.