1 10 2 https://theses.otagogeology.org.nz/files/original/dc5288529176a6f60244af5c62bcb4fe.pdf fc4cc34490646f9dd3be42e1382f9398 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((169.798292031391 -43.5293028095617,170.341206105389 -43.2440135055566,170.43216699032 -43.3127983353413,169.865109514897 -43.6045274335989,169.798292031391 -43.5293028095617))) Author last name Last name of the Author Williams Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? PhD Advisers Who supervised/advised this student Toy, V.G. Smith, S.A.F. Abstract The Abstract for this thesis The dynamic propagation of an earthquake rupture will generate inelastic deformation within its surrounding medium, culminating in the development of a fault damage zone. These are heavily fractured volumes of rock that flank the fault core, where the majority of displacement has been accommodated. Using the example of the Alpine Fault, I assess the mechanical and chemical processes associated with fault damage, which strongly condition the short and long term evolution of a fault. Approximately 70% of the oblique-dextral motion between the Australian and Pacific plates on the South Island of New Zealand is localised onto the Alpine Fault. A continuous record of its damage zone extending <30 m above its principal slip zones (PSZs) is provided by core recovered during the first phase of the Deep Fault Drilling Project (DFDP-1). A combination of visual core descriptions, X-ray and neutron tomographic core scanning, and X-ray diffraction demonstrate that the damage zone is epitomised by gouge-filled ‘phyllosilicate-enriched’ fractures. These contain a soft fine-grained fill, which have a relatively low density but are hydrogen-rich. Their bulk composition reflects both wear of the surrounding rock and phyllosilicate mineralisation during hydrothermal alteration. Fracture density in DFDP-1 core and field transects does not increase with proximity to the PSZs, but does systematically vary with lithology. By reorienting core sections with respect to geographically referenced borehole televiewer logs of the DFDP-1 boreholes, the true orientations of 637 fractures was obtained. Combined with field observations, these results indicate that damage zone fractures occupy a wide range of orientations. This reflects variable stress states adjacent to the Alpine Fault, which are generated by a fault trace that is non-planar in the near-surface, and non-optimally orientated with respect to the regional stresses at depth. The mechanical anisotropy of the foliated mylonites that host the damage zone cannot strongly influence fracturing. In field transects, broadly-oriented fractures are confined to within 50-150 m of the Alpine Fault, and this is the best estimate of damage zone width along its central section. This width is comparable to elsewhere along-strike. Therefore, the Alpine Fault is considered to be embedded within a tabular localised damage zone, as documented in other structurally mature crustal-scale faults. Petrological and scanning electron microscopy demonstrate that gouge-filled fractures extend to the micron scale where calcite, chlorite, K-feldspar and muscovite veins are also present. These veins and fractures form in a cyclic manner that may be operative throughout the Alpine Fault’s seismogenic zone. The documentation of some veins that cross-cut cataclasite textures requires that strain localisation from the 10-20 m thick Alpine Fault cataclasites to its 10-50 cm thick PSZ gouges must occur at depths <2-5 km. This study has sampled the Alpine Fault damage zone late in its cycle of stress accumulation. Within this period, micro and macro-scale fracture healing has occurred at distances <25 m of the PSZs. A combination of fluid over-pressures and unhealed damage elsewhere permit a Low Velocity Zone around the Alpine Fault. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/7360">http://hdl.handle.net/10523/7360</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. West Coast Thesis description Number of pages, maps, CDs, etc. 255 Pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2017Williams Creator An entity primarily responsible for making the resource Williams, Jack Nicholas (Jack) Date A point or period of time associated with an event in the lifecycle of the resource 2017 Title A name given to the resource The damage zone of New Zealand Subject The topic of the resource Structural Geology Alpine Fault Damage zones DFDP Fault healing Fault structure fractures https://theses.otagogeology.org.nz/files/original/185061ddc0df61ee4af2b71affb671f4.pdf 5550c8160d0d4a4cf560a0991bdd89c6 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Geology theses OU Geology thesis Thesis or dissertation completed by University of Otago Geology students Location WKT (WGS84) The location stored in WKT (WGS84) format MULTIPOLYGON (((170.38748098797 -43.265149244074,170.424934473365 -43.2659990625108,170.422899020371 -43.3141954428501,170.385416011598 -43.3133442005652,170.38748098797 -43.265149244074))) Author last name Last name of the Author Lepine Project type Is it an MSc, PhD, BSc(Hons) or PGDipSci? MSc Advisers Who supervised/advised this student Gorman, A.R. Abstract The Abstract for this thesis The glacio-fluvial sediments of the Whataroa Valley contain a geological record of environmental change that occurred as the valley was filled by sediments following the retreat of Pleistocene glaciers. This record is greatly affected by the significant motion that has occurred on the Alpine Fault over the same period. The Alpine Fault is the boundary between the Pacific and Australian tectonic plates, with uplift along the fault giving rise to the formation of the Southern Alps. For much of its length, the trace of the Alpine Fault is covered in sediments, so its precise position is not known. A series of hammer and weight drop seismic reflection lines collected in 2011, 2013 and 2015 image the sediments of the Whataroa Valley overlying the (presumably) glacially carved basement. This thesis uses these high-resolution seismic data for three purposes: 1) characterisation of sedimentary strata deposited in the valley while contributing to the multidisciplinary dataset characterising site 2 of the Deep Fault Drilling Project, 2) constraining the position of the Alpine Fault near surface trace on the coastal plain and 3), comparing and contrasting two different seismic sources that been used in data acquisition. The WhataDUSIE 3D survey conducted in 2011, consists of seven separate profiles on the eastern side of the Whataroa River on the hanging wall of the Alpine Fault. Each of these profiles was approximately 750 m in length, with a receiver spacing of 4 m and a shot spacing of 8 m. This survey was aimed at characterising the sedimentary strata in the Whataroa Valley in 3D. The Whataroa 2013 survey consists of four profiles totalling approximately 3 km in length. Geophone spacing was 5 m with shot points located between every second geophone (at a spacing of 10 m). Two of these profiles (4 and 5) were collected on the coastal plain running approximately perpendicular to the Alpine Fault. These lines were collected in an attempt to image the Alpine Fault in the near surface sediments. The other two profiles (1 and 2) lie on a river terrace and are orientated parallel to the Alpine Fault, and perpendicular to the valley wall. These two profiles characterise the sediments in the lowe r section of the Whataroa Valley and were collected as part of a larger data set for characterisation of the DFDP-2 drill site. The Whataroa 2015 survey was a re-shoot and extension of line 5 of the Whataroa 2013 survey. It made use of a weight drop seismic source and had a shot spacing of 10 m, with a 5 m receiver spacing. A comparison between the hammer seismic source and weight drop seismic source showed that while the frequencies of both sources were similar, the weight drop seismic source produced five times the energy and was a more repeatable source, leading to better quality data. Results of this study identified five main seismic facies, and the depth to basement within Whataroa Valley at the DFDP-2 drilling location. Offset reflections were also identified in the vicinity of the Alpine Fault surface trace. The sedimentary strata in Whataroa Valley have been divided into four facies: fluvial gravels (facies 1), Pleistocene marine sediments (facies 2), Pliocene marine sediments (facies 3) and a transition to basement (facies 4). Facies 5 represents a sudden change in signal strength in the northern sections of lines 4, 5 and 7. Within the marine and most recent glacio-fluvial deposits are offset reflections that do not propagate to the surface. These reflections have been interpreted to represent old Alpine Fault surface traces with offsets on the order of 10 to 25 m. There is a strong signal strength change identified in lines 4 and 7 that coincides with the proposed location of the Alpine Fault surface trace. Basement was only conclusively observed i n lines 1 and 2, occurring at a depth of 240 m near the DFDP-2 drill site. This was confirmed by rock cuttings from the borehole itself. OURArchive handle The handle from the Otago University Research Archive (OURArchive) <a href="http://hdl.handle.net/10523/6768">http://hdl.handle.net/10523/6768</a> OURArchvive access level Open Access Department The department where the student is studying primarily. Geology Named locality Named locality describing the field area location. Whataroa Valley West Coast Thesis description Number of pages, maps, CDs, etc. xiv, 153 pages A4 Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Identifier An unambiguous reference to the resource within a given context 2016Lepine Creator An entity primarily responsible for making the resource Lepine, Patrick Rafe Wadworth (Patrick) Date A point or period of time associated with an event in the lifecycle of the resource 2016 Title A name given to the resource Shallow Seismic Survey of the Whataroa Glacial Valley in the vicinity of the Alpine Fault, Westland Subject The topic of the resource Geophysics Alpine Fault DFDP Shallow Seismic