Search

found 232 results

Images for environmental; more images...

Research papers, Lincoln University

Within four weeks of the September 4 2010 Canterbury Earthquake a new, loosely-knit community group appeared in Christchurch under the banner of “Greening the Rubble.” The general aim of those who attended the first few meetings was to do something to help plug the holes that had already appeared or were likely to appear over the coming weeks in the city fabric with some temporary landscaping and planting projects. This article charts the first eighteen months of Greening the Rubble and places the initiative in a broader context to argue that although seismic events in Christchurch acted as a “call to palms,” so to speak, the city was already in need of some remedial greening. It concludes with a reflection on lessons learned to date by GTR and commentary on the likely issues ahead for this new mini-social-environmental movement in the context of a quake-affected and still quake-prone major New Zealand city. One of the key lessons for GTR and all of those involved in Christchurch recovery activities to date is that the city is still very much in the middle of the event and is to some extent a laboratory for seismic and agency management studies alike.

Research papers, University of Canterbury Library

During the 2010 - 2011 Canterbury earthquake sequence, extensive liquefaction was observed in many areas of Christchurch city and its surroundings, causing widespread damage to buildings and infrastructure. While existing simplified methods were found to work well in some areas of the city, there were also large areas where these methods did not perform satisfactorily. In some of these cases, researchers have proposed that layers of fine grained material within the soil profile may be responsible for preventing the manifestation of liquefaction. This paper presents preliminary findings on the mechanisms at play when pressure differentials exist across a clay layer. It is found that if the clay layer is unable to distort, then pore fluid is unable to break-through the layer even with relatively high pressures, resulting in dissipation of excess pore pressures by seepage. If the layers are however able to distort, then it is possible for the pore fluid to break through the clay layer, potentially resulting in adverse effects in terms of the severity of liquefaction.

Research papers, Victoria University of Wellington

©2019. American Geophysical Union. All Rights Reserved. Earthquakes have been inferred to induce hydrological changes in aquifers on the basis of either changes to well water-levels or tidal behavior, but the relationship between these changes remains unclear. Here, changes in tidal behavior and water-levels are quantified using a hydrological network monitoring gravel aquifers in Canterbury, New Zealand, in response to nine earthquakes (of magnitudes M w 5.4 to 7.8) that occurred between 2008 and 2015. Of the 161 wells analyzed, only 35 contain water-level fluctuations associated with “Earth + Ocean” (7) or “Ocean” (28) tides. Permeability reduction manifest as changes in tidal behavior and increased water-levels in the near field of the Canterbury earthquake sequence of 2010–2011 support the hypothesis of shear-induced consolidation. However, tidal behavior and water-level changes rarely occurred simultaneously (~2%). Water-level changes that occurred with no change in tidal behavior reequilibrated at a new postseismic level more quickly (on timescales of ~50 min) than when a change in tidal behavior occurred (~240 min to 10 days). Water-level changes were more than likely to occur above a peak dynamic stress of ~50 kPa and were more than likely to not occur below ~10 kPa. The minimum peak dynamic stress required for a tidal behavior change to occur was ~0.2 to 100 kPa.