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Rupert Sutherland: Influence Statistics

The Alpine Fault is an 850-km-long, continental dextral strike-slip fault that accommodates some 60%–90% (∼20–30 mm/yr) of the obliquely convergent motion between the Pacific and Australian Plates in South Island, New Zealand. The southern 230 km of the fault traverses the continental margin off Fiordland and intersects the subduction thrust at the northern end of the Puysegur Trench. Marine seismic reflection profiles and bathymetric data are used to evaluate the late Quaternary ...

The basement geology of New Zealand is composed of early Palaeozoic terranes of the Western Province, that are separated from late Palaeozoic–Mesozoic Eastern Province terranes by a suite of Carboniferous–Cretaceous arc-related igneous rocks (Median Tectonic Zone, MTZ). The Stokes Magnetic Anomaly System (SMAS) is associated with MTZ rocks and volcanogenic basement terranes of the Eastern Province. Offshore, it can be traced north along the northern margin of the New Caledonia Basin, and ...

We use seismic reflection and rock sample data to propose that the first-order physiography of New Caledonia Trough and Norfolk Ridge formed in Eocene and Oligocene time and was associated with the onset of subduction and back-arc spreading at the Australia-Pacific plate boundary. Our tectonic model involves an initial Cretaceous rift that is strongly modified by Cenozoic subduction initiation. Hence, we are able to explain (1) complex sedimentary basins of inferred Mesozoic age; (2) a ...

The MW 7.8 Dusky Sound earthquake of 2009 July 15 was the largest earthquake in New Zealand in the past ∼80 yr and is the only major subduction interface earthquake in the New Zealand historical record. We have estimated the coseismic and early post-seismic slip distribution in the earthquake by inversion of GPS and differential interferometric synthetic aperture radar (DInSAR) observations. We show that slip during the earthquake was highly oblique and essentially in the ...

Seismic–stratigraphic interpretations of a large new 2D seismic-reflection dataset from the Reinga Basin region northwest of New Zealand constrain the history of Cretaceous fragmentation of Gondwana and Cenozoic initiation of Tonga–Kermadec–Northland subduction. The southern Norfolk Ridge system lay in a proximal location to plate boundaries that were active during both Cretaceous and Cenozoic events, and persistent marine conditions led to a relatively complete record of sedimentation. ...

Ultrasonic image logs acquired in the DFDP‐2B borehole yield the first continuous, subsurface description of the transition from schist to mylonite in the hangingwall of the Alpine Fault, New Zealand, to a depth of 818 m below surface. Three feature sets are delineated. One set, comprising foliation and foliation‐parallel veins and fractures, has a constant orientation. The average dip direction of 145° is subparallel to the dip direction of the Alpine Fault, and the average dip ...

Seismic reflection profiles and multibeam bathymetric data are integrated to analyse the structure of the 25km-long strike-slip Dagg Basin associated with the marine section of the Alpine Fault, Fiordland, New Zealand. The basin is developing in almost 3000m water depth at a releasing bend, whilst contemporaneous transpression results in inversion of its southern end. Fiord-derived glacio-marine sediments flooded the basin during the last glaciation, and provide a stratigraphic framework ...

The southwest Pacific between Australia, New Zealand and New Caledonia is a block of continental crust, Zealandia, that moved away from Australia and Antarctica after a long period of subduction beneath eastern Gondwana. We use >100,000line-km of seismic-reflection profiles to identify intra-continental basins related to the Gondwana active margin, overlain with erosional unconformity by retrogradational strata. We interpret this regional-scale first-order unconformity, the Eastern ...

Since the Eocene, the Pacific—Australia plate boundary south of New Zealand has evolved from a spreading system into a transform boundary. Swath data acquired in the Southeast Tasman oceanic crust, between the Macquarie Ridge complex and the Resolution Ridge system, show that the spreading fabric changes orientation southwards along the Puysegur Trench, striking successively N60°E, N85°E and N120°E. This reflects the reorganisation of the plate boundary in response to changes in relative ...

Traveltimes between shots from nine marine seismic reflection lines and nine onshore recorders were used to construct a 3-D P wave velocity model of the northern Hikurangi subduction margin, New Zealand. From north to south between Raukumara Basin and Raukumara Peninsula, the Moho of the overriding plate increases in depth from 17 to ∼35 km. Low seismic P wave velocities of 3.5–5.0 km/s are localized within a ∼10 km thick prism in the lower crust of the overriding plate immediately updip ...

Study of Pliocene and Quaternary sediments west of the Alpine Fault in the Cascade valley, South Westland, New Zealand, has allowed determination of Alpine Fault displacement rate and coastal uplift rate over the last 3.5 m.y. Exposures of the Pliocene Halfway Formation (latest Opoitian‐Waipipian) are composed of marine sand and conglomerate deposited in c. 200–1000 m water depth. Beds are gently dipping and weakly deformed, with the direction of principal shortening oriented at a high ...

Eocene–Oligocene rifting, followed by Miocene–Quaternary strike-slip and obliquely convergent tectonics, are responsible for crustal thinning in the Solander Basin and subsequent development of the Puysegur oblique subduction zone, southwest New Zealand. Highly oblique convergence at a rate of 35 mm/yr is being partitioned between oblique subduction at the Puysegur trench, thrusting within the trench slope, strike-slip faulting on the Puysegur Bank, and minor shortening within the ...

The Alpine Fault is the main active structure in the oblique continental collision zone of South Island, New Zealand. It is continuous at the surface for ∼800 km and accommodates ∼70% of current plate motion. A 460 km offset of basement rocks suggests it has accommodated >50% of plate displacement since 45 Ma. Geophysical, geological, and contemporary kinematic data are successfully modeled by slip on a narrow Alpine Fault zone extending into the lower crust. The data are consistent with ...

The Hikurangi subduction margin, New Zealand, has not experienced any significant (>Mw 7.2) subduction interface earthquakes since historical records began ∼170 years ago. Geological data in parts of the North Island provide evidence for possible prehistoric great subduction earthquakes. Determining the seismogenic potential of the subduction interface, and possible resulting tsunami, is critical for estimating seismic hazard in the North Island of New Zealand. Despite the lack of ...

The Alpine Fault, New Zealand, is a major plate-bounding fault that accommodates 65-75% of the total relative motion between the Australian and Pacific plates. Here we present data on the hydrothermal frictional properties of Alpine Fault rocks that surround the principal slip zones (PSZ) of the Alpine Fault and those comprising the PSZ itself. The samples were retrieved from relatively shallow depths during phase 1 of the Deep Fault Drilling Project (DFDP-1) at Gaunt Creek. Simulated ...