Deep structure of a major subduction back thrust: Magneto-telluric investigations of the Taranaki Fault,New Zealand

A magneto-telluric (MT) pilot study is used to investigate the Taranaki Fault, a major thrust along the eastern margin of the Taranaki Basin, New Zealand. Analysis of the survey data (MT phase tensor analysis and 2D models), along a 25 km east–west oriented line perpendicular the fault, indicates the Taranaki Fault is the tectonic boundary between major Permian and Mesozoic basement terranes with differing resistivities. Models show the resistivity boundary at the fault dips eastward at about 45° to a depth of at least 12 km. These results suggest that the fault is a major long lived tectonic feature that formed in Mesozoic time during the terrane accretionary phase and has subsequently reactivated during the Cretaceous and Tertiary. At depths less than 5 km, MT models that use constraints from seismic and borehole data show low resistivity sediments extend about 4 km eastward, beneath the tip of the fault. The sedimentary succession beneath the thrust wedge is a petroleum exploration target and with a higher density of MT measurements, a better image of this region may be achieved.     

Are X-ray properties of loose groups different from those of compact groups?

We compare the X-ray properties of loose and compact galaxy groups, using a combined sample of 42 groups. We find that we are unable to separate loose and compact groups on the luminosity–temperature relation, the luminosity–velocity dispersion relation or the velocity dispersion–temperature relation using equally weighted errors. This suggests that the distinction between compact and loose groups is not a fundamental one, and we argue that a more useful distinction is that between X-ray bright and X-ray faint systems.
Given their similarity in X-ray properties, we combine the loose and compact subsamples to derive relations based on the full sample. This provides the highest statistical quality results to date on the way in which the correlations in X-ray properties of low‐mass systems depart from those seen in rich clusters.     

Selection of characteristic values and partial factors in geotechnical designs to Eurocode 7

The means by which reliability is achieved in designs to ENV 1997-1, the new CEN limit state prestandard for geotechnical design, is presented. In particular, the selection of characteristic strength values and partial factors is examined. A rational method is described for selecting characteristic strength values from limited test results and experience. The reason for three cases, with different partial factors, is explained. The example of an eccentrically loaded foundation illustrates how the controlling case may depend on the loading condition. The importance of using a geometrical factor in the design of an embedded retaining wall is demonstrated.     

Intensity attenuation for active crustal regions

We develop globally applicable macroseismic intensity prediction equations (IPEs) for earthquakes of moment magnitude M _W 5.0?C7.9 and intensities of degree II and greater for distances less than 300?km for active crustal regions. The IPEs are developed for two distance metrics: closest distance to rupture (R _rup) and hypocentral distance (R _hyp). The key objective for developing the model based on hypocentral distance??in addition to more rigorous and standard measure R _rup??is to provide an IPE which can be used in near real-time earthquake response systems for earthquakes anywhere in the world, where information regarding the rupture dimensions of a fault may not be known in the immediate aftermath of the event. We observe that our models, particularly the model for the R _rup distance metric, generally have low median residuals with magnitude and distance. In particular, we address whether the direct use of IPEs leads to a reduction in overall uncertainties when compared with methods which use a combination of ground-motion prediction equations and ground motion to intensity conversion equations. Finally, using topographic gradient as a proxy and median model predictions, we derive intensity-based site amplification factors. These factors lead to a small reduction of residuals at shallow gradients at strong shaking levels. However, the overall effect on total median residuals is relatively small. This is in part due to the observation that the median site condition for intensity observations used to develop these IPEs is approximately near the National Earthquake Hazard Reduction Program CD site-class boundary.     

Detection of Mixing Dynamics During Pumping of a Flooded Coal Mine

In complex hydrogeological environments the effective management of groundwater quality problems by pump‐and‐treat operations can be most confidently achieved if the mixing dynamics induced within the aquifer by pumping are well understood. The utility of isotopic environmental tracers (C‐, H‐, O‐, S‐stable isotopic analyses and age indicators—¹⁴C, ³H) for this purpose is illustrated by the analysis of a pumping test in an abstraction borehole drilled into flooded, abandoned coal mineworkings at Deerplay (Lancashire, UK). Interpretation of the isotope data was undertaken conjunctively with that of major ion hydrochemistry, and interpreted in the context of the particular hydraulic setting of flooded mineworkings to identify the sources and mixing of water qualities in the groundwater system. Initial pumping showed breakdown of initial water quality stratification in the borehole, and gave evidence for distinctive isotopic signatures (δ³⁴S(SO4) ? ?1.6‰, δ¹⁸O(SO₄) ? +15‰) associated with primary oxidation of pyrite in the zone of water table fluctuation—the first time this phenomenon has been successfully characterized by these isotopes in a flooded mine system. The overall aim of the test pumping—to replace an uncontrolled outflow from a mine entrance in an inconvenient location with a pumped discharge on a site where treatment could be provided—was swiftly achieved. Environmental tracing data illustrated the benefits of pumping as little as possible to attain this aim, as higher rates of pumping induced in‐mixing of poorer quality waters from more distant old workings, and/or renewed pyrite oxidation in the shallow subsurface.     

Seismic performance of non-structural components and contents in buildings: an overview of NZ research

This paper summarizes the research on non-structural elements and building contents being conducted at University of Canterbury in New Zealand. Since the 2010-2011 series of Canterbury earthquakes, in which damage to non-structural components and contents contributed heavily to downtime and overall financial loss, attention to seismic performance and design of non-structural components and contents in buildings has increased exponentially in NZ. This has resulted in an increased allocation of resources to research leading to development of more resilient non-structural systems in buildings that would incur substantially less damage and cause little downtime during earthquakes. In the last few years, NZ researchers have made important developments in understanding and improving the seismic performance of secondary building elements such as partitions, facades, ceilings and contents.     

A Farey story: the pioneer geologist John Farey (1766–1826)

John Farey was a pioneer British geologist whose work has been too long overlooked. His only major geological publication was concealed in what appears to be a local report on the agriculture and minerals of Derbyshire, commissioned by the Board of Agriculture and published in three volumes between 1811 and 1817. Farey also published an extraordinary amount in periodicals and prepared a remarkable series of geological maps and cross-sections which were never published, although a number of hand-drawn copies circulated and undoubtedly influenced the rise of stratigraphical geology.