title: Revising Z: part II - logical development

authors: Henson, Martin C.

subjects: specification language Z

abstract: This is the second of two related papers. In "Revising Z: Part I - logic and semantics" (this journal) we introduced a simple specification logic ZC comprising a logic and a semantics (in ZF set theory). We then provided an interpretation for (a rational reconstruction of) the specification language Z within ZC. As a result we obtained a sound logic for Z, including the basic schema calculus. In this paper we extend the basic framework with more sophisticated features (including schema operations) and we mount a critique of a number of concepts used in Z. We further demonstrate that the complications and confusions which these concepts introduce can be avoided without compromising expressibility.

text: Revising Z: part II - logical development This is the second of two related papers. In "Revising Z: Part I - logic and semantics" (this journal) we introduced a simple specification logic ZC comprising a logic and a semantics (in ZF set theory). We then provided an interpretation for (a rational reconstruction of) the specification language Z within ZC. As a result we obtained a sound logic for Z, including the basic schema calculus. In this paper we extend the basic framework with more sophisticated features (including schema operations) and we mount a critique of a number of concepts used in Z. We further demonstrate that the complications and confusions which these concepts introduce can be avoided without compromising expressibility.

year: 1999-12-01

title: Late Quaternary paleoseismic history of the Te Puninga Fault, Hauraki Plains, northern New Zealand

authors: Hughes, Joshua William

subjects: Te Puninga Fault

abstract: The Te Puninga Fault is a newly discovered active fault on the western side of the Hauraki Plains, northern North Island, New Zealand. Preliminary evidence in a 2016 study suggests that it may generate earthquakes Mw>6.8. Therefore, the fault presents a hazard and risk to the population and infrastructure of the Hauraki Plains region, including the population centres of Morrinsville and Te Aroha, and beyond. Several consequences from rupture of the Te Puninga Fault are likely: strong ground motion from earthquakes (possibly amplified by basin effect in the Hamilton Basin and Hauraki Plains); permanent surface deformation by fault surface rupture; and secondary effects such as liquefaction and landslides. Thus, it is important to better understand the seismicity of this fault to better understand the hazard and risk to the wider region. 
 
Paleoseismic trenching was undertaken in February 2021 along two fault traces at Ryland Trench and Arnold Trench. Exposures in the trenches enabled a stratigraphy to be established of the near-surface deposits (within 3 m) that were deformed by the fault. The deposits were described, and samples of organic material and tephra were collected. The organic material was submitted to the Waikato Radiocarbon Dating Laboratory for radiocarbon (¹⁴C) dating, and major element analysis of volcanic glass was undertaken at the electron probe microanalysis (EPMA) facility, Victoria University of Wellington. The bulk of the deposits exposed in each trench comprised secondary volcaniclastic sediments of the Hinuera Formation. An additional alluvial unit, deposited after 11,000 cal yr BP, was identified in the Ryland trench and correlated with the Waitoa Formation. The ¹⁴C dating indicated that the Hinuera Surface at each trench site was abandoned at approximately 24,000 cal yr BP. At both trenches, the Hinuera Surface was overlain by a cover bed of composite tephras deposited incrementally whilst being transformed pedologically (via pedogenic upbuilding) to form Allophanic Soils on well to moderately well drained higher landscape positions. Major element analysis of glass shards isolated from the base of the composite tephra column suggests that the Okareka (23,500 cal yr BP) or Rerewhakaaitu (17,600 cal yr BP), or both, (crypto)tephras were present, generally supporting the age ascribed to the Hinuera Surface (c. 24.0 cal ka) based on the ¹⁴C age modelling. The Taupo (1718 ± 10 cal yr BP) and Kaharoa (636 ± 12 cal yr BP) tephras occurred in the upper parts of both trenches as visible, thin, discontinuous deposits. They were identified by their stratigraphic superpositioning and physical properties, confirmed by their diagnostic ferromagnesian minerals and glass-shard major element compositions. 

A site near Quine Road where the fault scarp dipped westwards, in the opposite direction to the eastward slope of the general land surface, and intersected stream terraces, was identified using high resolution LiDAR data. Using a digital elevation model, a hillshade model, and field work including geomorphic mapping, the terraces formed by the streams were identified and labelled from 1 (youngest) to 8 (oldest). Because terraces became progressively younger as they descended from the c. 24 cal ka Hinuera Surface, they can be used as chronological markers for fault activity. If the scarps formed by fault surface ruptures represent different surface displacement of different terraces, an analysis can be done to assess numbers and timing of fault ruptures. Elevation profiles were drawn parallel and perpendicular to the fault and it was found that the vertical fault displacement decreased as the terraces got younger. By comparing two models for incision rates, terrace ages were modelled and thus possible ages of displacement were obtained. The oldest terraces had an average vertical displacement of 2.6 ± 0.15 m, whereas Terrace 3 had a vertical displacement of 1.0 ± 0.15 m, and the youngest two had no vertical displacement. Therefore, it is likely that the penultimate earthquake that generated the displacement occurred between the formation of Terrace 4 (19,500 ± 1,400 yrs BP) and Terrace 3 (18,600 ± 600 yrs BP), and the most recent earthquake occurred between the formation of Terraces 3 (18,600 ± 600 yrs BP) and 2 (15,000 ± 1,900 yrs BP). Using the age of the youngest terrace that was displaced in two events (19,500 yrs BP), and the average vertical displacement of the other terraces displaced twice (2.64 ± 0.15 m), a slip rate of 0.135 ± 0.01 mm/yr was calculated. As this is one of at least nine strands of the Te Puninga Fault at this latitude, is a possible the 2016 published slip rate of 0.160 ± 0.03 mm/yr is understated. 

A trial investigation of ground penetrating radar (GPR) at three locations on the Te Puninga Fault was conducted. The first two applications were at each of the two paleoseismic trench sites (Arnold and Ryland trenches), and hence the reflectors could be compared to the known stratigraphy, and the third at the Quine Road study site. The Quine Road site is a possible future trench location. The GPR investigation found: a) that a suitable depth of stratigraphy (<2.5 m) could be obtained; b) the displaced surfaces at all three sites were formed by seismic deformation rather than fluvial erosional processes because the reflectors in the radargrams ran parallel to the land surface, reflecting folding; and c) at  Quine Road, in contrast, the sediments potentially show clear faulting rather than folding which could provide key information if trenching were to be undertaken at the site.

text: Late Quaternary paleoseismic history of the Te Puninga Fault, Hauraki Plains, northern New Zealand The Te Puninga Fault is a newly discovered active fault on the western side of the Hauraki Plains, northern North Island, New Zealand. Preliminary evidence in a 2016 study suggests that it may generate earthquakes Mw>6.8. Therefore, the fault presents a hazard and risk to the population and infrastructure of the Hauraki Plains region, including the population centres of Morrinsville and Te Aroha, and beyond. Several consequences from rupture of the Te Puninga Fault are likely: strong ground motion from earthquakes (possibly amplified by basin effect in the Hamilton Basin and Hauraki Plains); permanent surface deformation by fault surface rupture; and secondary effects such as liquefaction and landslides. Thus, it is important to better understand the seismicity of this fault to better understand the hazard and risk to the wider region. 
 
Paleoseismic trenching was undertaken in February 2021 along two fault traces at Ryland Trench and Arnold Trench. Exposures in the trenches enabled a stratigraphy to be established of the near-surface deposits (within 3 m) that were deformed by the fault. The deposits were described, and samples of organic material and tephra were collected. The organic material was submitted to the Waikato Radiocarbon Dating Laboratory for radiocarbon (¹⁴C) dating, and major element analysis of volcanic glass was undertaken at the electron probe microanalysis (EPMA) facility, Victoria University of Wellington. The bulk of the deposits exposed in each trench comprised secondary volcaniclastic sediments of the Hinuera Formation. An additional alluvial unit, deposited after 11,000 cal yr BP, was identified in the Ryland trench and correlated with the Waitoa Formation. The ¹⁴C dating indicated that the Hinuera Surface at each trench site was abandoned at approximately 24,000 cal yr BP. At both trenches, the Hinuera Surface was overlain by a cover bed of composite tephras deposited incrementally whilst being transformed pedologically (via pedogenic upbuilding) to form Allophanic Soils on well to moderately well drained higher landscape positions. Major element analysis of glass shards isolated from the base of the composite tephra column suggests that the Okareka (23,500 cal yr BP) or Rerewhakaaitu (17,600 cal yr BP), or both, (crypto)tephras were present, generally supporting the age ascribed to the Hinuera Surface (c. 24.0 cal ka) based on the ¹⁴C age modelling. The Taupo (1718 ± 10 cal yr BP) and Kaharoa (636 ± 12 cal yr BP) tephras occurred in the upper parts of both trenches as visible, thin, discontinuous deposits. They were identified by their stratigraphic superpositioning and physical properties, confirmed by their diagnostic ferromagnesian minerals and glass-shard major element compositions. 

A site near Quine Road where the fault scarp dipped westwards, in the opposite direction to the eastward slope of the general land surface, and intersected stream terraces, was identified using high resolution LiDAR data. Using a digital elevation model, a hillshade model, and field work including geomorphic mapping, the terraces formed by the streams were identified and labelled from 1 (youngest) to 8 (oldest). Because terraces became progressively younger as they descended from the c. 24 cal ka Hinuera Surface, they can be used as chronological markers for fault activity. If the scarps formed by fault surface ruptures represent different surface displacement of different terraces, an analysis can be done to assess numbers and timing of fault ruptures. Elevation profiles were drawn parallel and perpendicular to the fault and it was found that the vertical fault displacement decreased as the terraces got younger. By comparing two models for incision rates, terrace ages were modelled and thus possible ages of displacement were obtained. The oldest terraces had an average vertical displacement of 2.6 ± 0.15 m, whereas Terrace 3 had a vertical displacement of 1.0 ± 0.15 m, and the youngest two had no vertical displacement. Therefore, it is likely that the penultimate earthquake that generated the displacement occurred between the formation of Terrace 4 (19,500 ± 1,400 yrs BP) and Terrace 3 (18,600 ± 600 yrs BP), and the most recent earthquake occurred between the formation of Terraces 3 (18,600 ± 600 yrs BP) and 2 (15,000 ± 1,900 yrs BP). Using the age of the youngest terrace that was displaced in two events (19,500 yrs BP), and the average vertical displacement of the other terraces displaced twice (2.64 ± 0.15 m), a slip rate of 0.135 ± 0.01 mm/yr was calculated. As this is one of at least nine strands of the Te Puninga Fault at this latitude, is a possible the 2016 published slip rate of 0.160 ± 0.03 mm/yr is understated. 

A trial investigation of ground penetrating radar (GPR) at three locations on the Te Puninga Fault was conducted. The first two applications were at each of the two paleoseismic trench sites (Arnold and Ryland trenches), and hence the reflectors could be compared to the known stratigraphy, and the third at the Quine Road study site. The Quine Road site is a possible future trench location. The GPR investigation found: a) that a suitable depth of stratigraphy (<2.5 m) could be obtained; b) the displaced surfaces at all three sites were formed by seismic deformation rather than fluvial erosional processes because the reflectors in the radargrams ran parallel to the land surface, reflecting folding; and c) at  Quine Road, in contrast, the sediments potentially show clear faulting rather than folding which could provide key information if trenching were to be undertaken at the site.

year: 2023

title: When Two Worlds Collide: Mātauranga Māori, Science and Health of the Toreparu Wetland

authors: Robb, Mahuru Joyce Gordon

subjects: Mātauranga Māori

abstract: Much of our understanding of wetland health and function comes from scientific-based monitoring and methodologies. However, there is a wealth of knowledge to be gained from Māori-value based assessment methods for monitoring wetlands in New Zealand. I used the Wetland Cultural Health Index (WCHI) and a variety of scientific wetland survey methods to examine how these two approaches complement each other. For this research, I worked with the people from Mōtakotako marae at the Toreparu wetland (Waikato), developing a set of site specific cultural indicators. 
Comparative analysis revealed a range of similarities and differences between the WCHI indices and scientific parameters. We found that as Wetland Cultural Health Measure (WCHM) scores increased, there was also an increase in dissolved oxygen concentration, SQMCI-sb values, and total nitrogen concentrations. Cultural indices provided an overall indication of site health. It was apparent, however, that scores of contributing indicators could vary markedly at any one site. As such, high scores for some indicators (e.g., vegetation values) may obscure low values for other variables (e.g., water quality), providing an index that depicts site health as being of average condition. 
Capacity and resourcing issues were also highlighted as being an issue for Māori to be able to successfully carry out wetland monitoring, but also for staff in councils and other research and environmental governing bodies to build and maintain relationships with tangata whenua. Other challenges around site access provided a unique opportunity to develop and trial new WCHI assessment techniques. The use of video assessment to carry out WCHI monitoring was of varying success. Indicators that could be scored by visual assessment were useful, but indicators that relied on sound or felt sensation were difficult to assess. The use of mauri (life force) as an indicator had benefits when applied to the whole catchment, but the volunteer participants challenged its validity when used at the smaller site scale. Volunteers found assigning a numerical value to mauri very difficult, and felt that reducing mauri to a single number may diminish the significance of this holistic and metaphysical concept.  Mauri has been used successfully as a measure of environmental health but it is important to communicate and understand what mauri is and why it is measured.
Overall, the WCHI provided a wealth of information that could not be captured through scientific sampling, such as the presence of dye source, loss of bird/fish species and baseline information on the past condition of the Toreparu before the surrounding land was converted for agricultural use. This confirms that our understanding of wetland health is enhanced through the inclusion of cultural values.
As the New Zealand government and Māori move towards a future of collaborative research and management of freshwater ecosystems, there is a need for greater understanding around cultural values and priorities. By using both scientific and Māori-value based wetland monitoring methods, Māori can articulate a range of values, goals and priorities to help inform environmental decision makers and empower iwi and hapū to have a meaningful and sustainable role in the management of wetlands.  There needs to be a foundation of mutual understanding and relationships built between environmental governing bodies and Māori for the future success of collaborative research and management of New Zealand's wetlands.

text: When Two Worlds Collide: Mātauranga Māori, Science and Health of the Toreparu Wetland Much of our understanding of wetland health and function comes from scientific-based monitoring and methodologies. However, there is a wealth of knowledge to be gained from Māori-value based assessment methods for monitoring wetlands in New Zealand. I used the Wetland Cultural Health Index (WCHI) and a variety of scientific wetland survey methods to examine how these two approaches complement each other. For this research, I worked with the people from Mōtakotako marae at the Toreparu wetland (Waikato), developing a set of site specific cultural indicators. 
Comparative analysis revealed a range of similarities and differences between the WCHI indices and scientific parameters. We found that as Wetland Cultural Health Measure (WCHM) scores increased, there was also an increase in dissolved oxygen concentration, SQMCI-sb values, and total nitrogen concentrations. Cultural indices provided an overall indication of site health. It was apparent, however, that scores of contributing indicators could vary markedly at any one site. As such, high scores for some indicators (e.g., vegetation values) may obscure low values for other variables (e.g., water quality), providing an index that depicts site health as being of average condition. 
Capacity and resourcing issues were also highlighted as being an issue for Māori to be able to successfully carry out wetland monitoring, but also for staff in councils and other research and environmental governing bodies to build and maintain relationships with tangata whenua. Other challenges around site access provided a unique opportunity to develop and trial new WCHI assessment techniques. The use of video assessment to carry out WCHI monitoring was of varying success. Indicators that could be scored by visual assessment were useful, but indicators that relied on sound or felt sensation were difficult to assess. The use of mauri (life force) as an indicator had benefits when applied to the whole catchment, but the volunteer participants challenged its validity when used at the smaller site scale. Volunteers found assigning a numerical value to mauri very difficult, and felt that reducing mauri to a single number may diminish the significance of this holistic and metaphysical concept.  Mauri has been used successfully as a measure of environmental health but it is important to communicate and understand what mauri is and why it is measured.
Overall, the WCHI provided a wealth of information that could not be captured through scientific sampling, such as the presence of dye source, loss of bird/fish species and baseline information on the past condition of the Toreparu before the surrounding land was converted for agricultural use. This confirms that our understanding of wetland health is enhanced through the inclusion of cultural values.
As the New Zealand government and Māori move towards a future of collaborative research and management of freshwater ecosystems, there is a need for greater understanding around cultural values and priorities. By using both scientific and Māori-value based wetland monitoring methods, Māori can articulate a range of values, goals and priorities to help inform environmental decision makers and empower iwi and hapū to have a meaningful and sustainable role in the management of wetlands.  There needs to be a foundation of mutual understanding and relationships built between environmental governing bodies and Māori for the future success of collaborative research and management of New Zealand's wetlands.

year: 2014