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The evolution of the continental intraarc Taupo Rift in the North Island, New Zealand, is rapid, significantly faster than comparative intracontinental rifts such as the African Rifts. Based on our faulting data and published geological, geophysical, and borehole data, we show that activity in the ~2 Ma Taupo Rift has rapidly and asymmetrically narrowed via inward and eastward migration of faulting (at rates of approximately 30 km Myr−1and 15 km Myr−1, respectively) and has propagated southward along its axis ~70 km in 350 kyr. The loci of voluminous volcanic eruptions and active faulting are correlated in time and space, suggesting that a controlling factor in the rapid rift narrowing is the presence of large shallow heterogeneities in the crust, such as large rhyolitic magma bodies generated by subduction processes, which weaken the crust and localize deformation. Eastward migration of faulting also follows the eastward migration of the volcanic arc which may be related to rollback of the Pacific crust slab at the Hikurangi subduction zone. Southward propagation of the rift is linked with southward migration of the Hikurangi Plateau/Chatham Rise subduction point and occurs episodically aided by stress changes associated with voluminous local volcanism. The large magma supply during early continental intraarc rift stages explains faster evolution (from tectonic to magmatic) than intracontinental rifts. However, the fast changes in magma supply from the subduction zone can also lead to evolution reversals (more evolved magmatic stages reverting to less evolved tectonic stages), rift cessation, and thus failed continental breakup. The Taupo Rift evolves through asymmetric inward migration of boundary faults (width narrowing) and along‐strike propagationComparison between Taupo Rift and subduction and intraplate rifts suggests that the former evolves faster in particular during early stagesShallow voluminous magmatism aids episodic rifting. Evolution reversals (from magmatic to tectonic) also occur in subduction rifts

ABSTRACTAt the eastern boundary of the south Taupo Rift, the NE-striking, rift-bounding Rangipo and the ENE-striking Wahianoa active normal faults intersect. We investigate their intersection at the Upper Waikato Stream to understand the kinematics of a rift termination in an active volcanic area. The Upper Waikato Stream Fault is a previously unrecognised seismogenic source also at the eastern boundary, capable of producing a MW6.5 and up to MW7.1 earthquake if it ruptures in conjunction with the Rangipo or Wahianoa faults. We found a minimum of 12 surface-rupturing earthquakes in the last 45.16 ka on the Upper Waikato Stream Fault (mean slip-rate c. 0.5 mm/yr), and a minimum of nine surface-rupturing earthquakes in the last 133 ka on the Wahianoa Fault (mean slip-rate c. 0.2 mm/yr). Periods of highest slip-rate on these faults may coincide in time with Taupo, Ruapehu or Tongariro eruptions, but, despite their intersection, movement was not coincident across all faults. The Upper Waikato Stream Fault responded to a major Taupo Volcano eruption, the Wahianoa to a major eruptive sequence from Mt Tongariro and the Rangipo to major explosive events from Mt Ruapehu.

Active fault traces are a surface expression of permanent deformation that accommodates the motion within and between adjacent tectonic plates. We present an updated national-scale model for active faulting in New Zealand, summarize the current understanding of fault kinematics in 15 tectonic domains, and undertake some brief kinematic analysis including comparison of fault slip rates with GPS velocities. The model contains 635 simplified faults with tabulated parameters of their attitude (dip and dip-direction) and kinematics (sense of movement and rake of slip vector), net slip rate and a quality code. Fault density and slip rates are, as expected, highest along the central plate boundary zone, but the model is undoubtedly incomplete, particularly in rapidly eroding mountainous areas and submarine areas with limited data. The active fault data presented are of value to a range of kinematic, active fault and seismic hazard studies.

AbstractThe Canterbury earthquake sequence of 2010–2011 is the most significantly impacting event in New Zealand since World War II, consuming >15% of New Zealand's GDP. In Canterbury, geoscience information has contributed significantly to civil defence response management and more recently to the recovery effort coordinated through the Canterbury Earthquake Recovery Authority (CERA) and local authorities in Canterbury. The earthquakes have resulted in major social, community, education and economic disruption, and created considerable uncertainty in relation to the feasibility of land remediation in liquefaction-damaged areas. Analysis of voluminous geoscience, engineering and social science data has and will continue to underpin decisions on the appropriate time to begin infrastructure, residential and commercial rebuild and on whether building codes are appropriate to protect society from rare but potentially catastrophic events.

Coastlines that trend both parallel and normal to the Hikurangi subduction margin along the Raukumara Peninsula, New Zealand, provide a globally unique situation that enables study of the coastal deformation and its spatial variance across and along the forearc. The data suggest there is margin-parallel zoning of the forearc deformation processes across the Raukumara segment of the Hikurangi margin. On forearc promontories closest to the Hikurangi trench (within 80 km), Holocene marine and fluvial terraces record localised zones of intermittent uplift driven by large coseismic events on landward-dipping nearshore reverse faults. At greater distances from the trench (>100 km), Holocene and Pleistocene coastal stratigraphy and geomorphology suggest that surface uplift occurs by a gradual mechanism: either by frequent small earthquakes or by an aseismic process. In concurrence with geophysical models, we suggest the gradual uplift of this area is most likely driven by the buoyancy of underplated sediment with a contribution from subduction of the over-thickened crust of the Hikurangi Plateau. There is an intermediate zone at c. 80-100 km from the trench that is uplifted at low to moderate rates, probably by the effects of Hikurangi Plateau subduction with some contributions from outboard upper plate faulting and inboard sediment underplating.

Six trenches and additional exposures have been investigated along a 23 km length of the Pahiatua section of the Wellington Fault. The sites show a consistent fault rupture record for the last four surface-faulting events along the Pahiatua section. This multi-site record of events, supported by 28 radiocarbon ages that span the last c. 4500 yr, is the most complete paleoseismic record for the Wellington Fault. From southwest to northeast, the trenches are called Death-1 and -2, Hughes-2 and -1, and Ebbett-2 and -1, named after local farmers. Additional data come from an exposure at the Army Depot northeast of Ebbett-1 and a stream cutting near the Death-1 trench. Earthquake events are recognised on the basis of upward terminations of faults and stratigraphic evidence (unconformities; scarp-derived colluvial deposits; “co-seismically” generated, organic, poorly sorted units; and subsequent scarp-ponded units).On this basis, evidence for the most recent surface-faulting event is recognised at all sites (i.e., between Death-1 and the Army Depot site) and has a timing of AD 1670-1800 (150-280 cal. yr BP). The penultimate faulting event has been recognised at all six trenches and occurred between AD 690 and 1170 (780-1260 cal. yr BP). Clear evidence, and datable material associated with events III and IV, is observed only in the older records of the Ebbett-1 and Hughes trenches. Event III is bracketed by faulting and two ages on co-seismic deposits to the interval AD 65 to 400 BC (1885-2350 cal. yr BP). Event IV is bracketed by three key ages in the Hughes-1 trench to the interval 1600-2140 BC (3550-4090 cal. yr BP). The trench-derived recurrence interval based on these four events is c. 1200 ±110 yr, which is consistent with, though longer than, an estimate of the recurrence interval based on slip rate (5.1-6.2 mm/yr) and single-event displacement (4.5 ± 1 m), which gave a range of 820 ± 260 yr.When the current paleoseismic data for the Wellington Fault are considered together, they suggest that: (1) the last four large earthquakes along the Pahiatua section have involved rupture of the entire section; (2) these events broadly correlate with other dated paleoearthquake events along the Wellington-Hutt Valley segment and Tararua section of the fault, and the southern end of the Mohaka Fault; (3) the most recent faulting event along the Pahiatua section is somewhat younger than for the Wellington-Hutt Valley segment or Tararua section; and (4) either single or dual segment/section rupture scenarios existed along these four fault sections.

To understand the tectonic evolution of the southern termination of the Taupo Volcanic Zone (TVZ), New Zealand, we compare the late Quaternary structure and kinematics of the southern part of the Taupo Rift or Taupo Fault Belt (Mt Ruapehu Graben) with central parts of the rift (Ngakuru Graben), and with the South Wanganui Basin. We also investigate the differences between displacements of Pliocene and late Quaternary markers within the southern Taupo Rift. Comparison of fault displacement rates derived from displacements of late Quaternary and Pliocene markers yields a preliminary estimate of <400 000 yr for fault initiation of the majority of faults in the southern Taupo Rift. The timing of the onset of faulting in the southern TVZ appears to be younger than central parts of the TVZ and may indicate a step-wise southward propagation of the rift. Faulting also appears to be less evolved in the south than in the central parts of the Taupo Rift (thicker seismogenic crust and hence wider fault spacing), reinforcing the impression of a recent incremental propagation of the Taupo Rift to the south. The onset of faulting coincides with independent observations of the initiation of volcanism in the southern TVZ. We propose that the termination of the TVZ, geographically short of the limit of the Hikurangi margin, may only be temporary, and it is most likely to propagate southward in association with future major perturbations in the subduction margin, such as the occurrence of large ignimbrite volcanism.

Late Quaternary structure and kinematics at the southern termination of the Taupo Rift are investigated by means of active fault mapping and estimates of fault displacement and extension rates. Active faults in the southern Taupo Rift are normal in sense and include three major structures: the NNE-trending Mt Ruapehu Graben; the E-W to ESE-WNW-trending Ohakune-Raetihi fault set; and the NE-trending Karioi fault set. Displacements of young geomorphic features, fault plane exposures in roadcuts, and trenches across faults show that all faults are active contemporaneously. The Mt Ruapehu Graben is the southern extension of the modern (i.e., <26 ka) Taupo Rift (or Taupo Fault Belt, TFB), and has developed as a result of backarc extension related to the Hikurangi subduction margin. Geologic extension rate for the Mt Ruapehu Graben is estimated here at 2.3 ± 1.2 mm/yr. The other two structures strike almost perpendicular to the Taupo Rift terminating the Mt Ruapehu Graben to the south. The co-existence of three normal fault sets in mutual cross-cutting relations and with no significant strike-slip on any of them may be related to local reorientation of the minimum principal stress axis (σ3) or to a stress tensor where |σ3| ≈ |σ2|. Complicated strains at the southern termination of the Taupo Rift are related to block rotations in the Hikurangi subduction margin.

The Wellington Fault is a major active, right lateral, strike-slip fault in southern North Island that can be divided into three distinct geometric sections based on changes in neotectonic character and structural complexities. These are, from south to north: the Wellington-Hutt Valley segment; Tararua section; and Pahiatua section. The Pahiatua section is a 42 km long, straight, NNE-striking fault section defined between two geometric endpoints near Putara in the south and Woodville. This section has been mapped in detail and exhibits classic strike-slip tectonic geomorphology and late Quaternary dextral displacements of up to 125 m. Three trenches excavated at sites along the Pahiatua section are used to define the dextral slip rate for this section. At Bennett trench site, a stream is dextrally deflected 50 ± 6 m. Peaty silts underlying “deflected” channel deposits in the trench yield an age of 8390-8700 cal. yr BP, providing a minimum dextral slip rate of 5.1-6.7 mm/yr. At Hughes 1 site, a stream is deflected 60 ± 5 m. Peaty material found stratigraphically above the deflection there was dated (10 500-11 160 cal. yr BP), yielding a maximum slip rate of 4.9-6.2 mm/yr for this displacement. Ebbett 1 trench was excavated across the fault zone where a smaller displacement (18 ± 2 m) yielded a slip rate range of 3.2-5.2 mm/yr. Our preferred dextral slip rate (5.1-6.2 mm/yr) comes from the combination of the minimum and maximum rates from Bennett and Hughes 1 sites. This range is generally lower than (but slightly overlaps) that for the Wellington-Hutt Valley segment (6-7.6 mm/yr). The single-event displacement range for the Pahiatua section determined from field measurements is 4.5 ± 1 m. From this data we calculate a recurrence interval for surface-rupturing earthquakes of 564-1080 yr.The overlap of results from both the Pahiatua section and the Wellington-Hutt Valley segment allow us to assess the likely slip rate, single-event displacement, recurrence interval range, and characteristics of the 53 km long, bush-covered Tararua section of the Wellington Fault. The data show that both the Pahiatua and Tararua sections: (1) are moderate slip rate, strike-slip fault sections; (2) produce multi-metre single-event dextral displacements; (3) have short recurrence intervals; and (4) individually have the capability to generate surface-rupturing earthquakes of Mw > 7.

Eleven sand layers occur within Holocene low-energy estuarine and marginal marine sequences of blue-grey silty clay at two sites on the coastal plain between Wairoa and Mahia Peninsula, northern Hawke's Bay, New Zealand. The sedimentology and fossil assemblages of these layers are consistent with deposition by high-energy influxes to the sites. Three influxes are terrestrial in nature and are thought to represent alluvial flood events. All other sand layers are marine derived and are likely to be the result of storm surges or tsunami. Tsunami inundation is favoured for two sand layers that occur in association with evidence for sudden subsidence at c. 6300 and c. 4800 yr BP The c. 6300 yr inundation also coincides with previously identified evidence for a tsunami at a site 10 km westwards along the coast. Further investigation is required to distinguish between tsunami and storm surge deposition for the remaining six layers.

The Hurunui section of the Hope Fault is a newly defined, 42 km long geomorphic fault section which extends from Harper Pass to the Hope-Boyle River confluence. Reconnaissance mapping along the Hurunui section from Hope Shelter to Harper Pass provided new data on its location, geomorphology, displacement, and slip rate. More than 200 previously published field observations of dextrally and vertically displaced landforms along the fault provide data on the distribution of displacement along the fault trace. Five radiocarbon dates found in association with offset geomorphic features are presented and two new measures of dextral slip rate are calculated. At McKenzie Stream, a late Holocene fan complex is cut by the Hope Fault. Young abandoned and active channels on this surface show dextral offsets of up to 22 ± 2 m along a south-facing scarp with a height of up to 5 m. Woody litter from a unit in this complex has yielded a radiocarbon age of 2331 ±55 yr BP and a corresponding minimum horizontal slip rate of 8.1-11.0 mm/yr. At Macs Knob, large dextral deflections of stream catchments are linked to episodes of glacial resetting of the landscape. Correlation of the offset of “Macs stream” (166 ± 17 m) with a post-Aranuian age peat (10 782 ± 60 yr BP) yields a maximum horizontal slip rate of 13.0 ± 1.5 mm/yr. The single-event dextral displacement, based on offset stream channels at McKenzie fan, is 3.2-3.8 m (av. c. 3.4 m). The ratio of dextral to vertical slip is c. 7 ± 2:1, indicating that the Hope Fault has a dominantly strike-slip sense of motion.The average recurrence interval for the last 5-7 events (i.e., to produce 19-24 m slip at McKenzie fan) is 310-490 yr. The age of the most recent surface-rupturing earthquake at this site is not known, though felt effects, fault scaling, and landscape arguments indicate it was not the AD 1888 North Canterbury earthquake.

The design of potent and selective non-peptide antagonists of endothelin-1 (ET-1) and its related isopeptides are important tools defining the role of ET in human diseases. In this report we will describe the detailed structure−activity relationship (SAR) studies that led to the discovery of a potent series of butenolide ETA selective antagonists. Starting from a micromolar screening hit, PD012527, use of Topliss decision tree analysis led to the discovery of the nanomolar ETA selective antagonist PD155080. Further structural modifications around the butenolide ring led directly to the subnanomolar ETA selective antagonist PD156707, IC50's = 0.3 (ETA) and 780 nM (ETB). This series of compounds exhibited functional activity exemplified by PD156707. This derivative inhibited the ETA receptor mediated release of arachidonic acid from rabbit renal artery vascular smooth muscle cells with an IC50 = 1.1 nM and also inhibited the ET-1 induced contraction of rabbit femoral artery rings (ETA mediated) with a pA2 = 7.6. PD156707 also displayed in vivo functional activity inhibiting the hemodynamic responses due to exogenous administration of ET-1 in rats in a dose dependent fashion. Evidence for the pH dependence of the open and closed tautomerization forms of PD156707 was demonstrated by an NMR study. X-ray crystallographic analysis of the closed butenolide form of PD156707 shows the benzylic group located on the same side of the butenolide ring as the γ-hydroxyl and the remaining two phenyl groups on the butenolide ring essentially orthogonal to the butenolide ring. Pharmacokinetic parameters for PD156707 in dogs are also presented.

The Wellington Fault is one of the major active right-lateral strike-slip faults of the southern North Island and represents a significant seismic hazard to the greater Wellington region. Trench excavations across the fault in the Long Gully/Karori Reservoir area and near Kaitoke, along with Quaternary stratigraphic and soil studies at Te Mania, indicate that the most recent surface rupture event along the southern portion of the Wellington Fault was 300-450 cal B .P. (calendar years before A.D. 1950) and the next oldest event was 670-830 cal B.P. The elapsed time between these two events is 220-530 years. Based on the previously reported 6.0-7.6 mm/yr, long-term (c. 140 ka), average, horizontal slip rate calculated at Emerald Hill, and the 3.2-4.7 m single-event offsets (the five most recent events) measured at Te Marua, the average recurrence interval for this portion of the Wellington Fault is 420-780 years.At the Long Gully trench site, two stream channels are laterally displaced by c. 50 m. Displacement has resulted in the ponding of the streams behind an uphill-facing bedrock scarp. The ponding began about 10 ka, as inferred from the age of the oldest organic material exposed in the trench excavations. The average lateral slip rate in the Long Gully area is thus c. 5 mm/yr.Recent surface fault movements at Long Gully, Te Mania, and Kaitoke have similar timings, suggesting that the 75 km long section of the Wellington Fault extending from Cook Strait to Kaitoke comprises a single fault-rupture segment: the Wellington - Hutt Valley Segment.