43,690 research outputs found
Microearthquake slip increments recorded in quartz slikenfibers, Chrystalls Beach accretionary complex, New Zealand
No full textShear veins observed within anisotropic fabric at high angles to the maximum compressive stress
No full textSome faults seem to slip at unusually high angles (>45°) relative to the orientation of the greatest principal compressive stress. This implies that these faults are extremely weak compared with the surrounding rock. Laboratory friction experiments and theoretical models suggest that the weakness may result from slip on a pre-existing frictionally weak surface, weakening from chemical reactions, elevated fluid pressure or dissolution–precipitation creep. Here we describe shear veins within the Chrystalls Beach accretionary mélange, New Zealand. The mélange is a highly sheared assemblage of relatively competent rock within a cleaved, anisotropic mudstone matrix. The orientation of the shear veins—compared with the direction of hydrothermal extension veins that formed contemporaneously—indicates that they were active at an angle of 80°±5° to the greatest principal compressive stress. We show that the shear veins developed incrementally along the cleavage planes of the matrix. Thus, we suggest that episodic slip was facilitated by the anisotropic internal fabric, in a fluid-overpressured, heterogeneous shear zone. A similar mechanism may accommodate shear at high angles to the greatest principal compressive stress in a range of tectonic settings. We therefore conclude that incremental slip along a pre-existing planar fabric, coupled to high fluid pressure and dissolution–precipitation creep, may explain active slip on severely misoriented faults
Incrementally Developed `Dilational Hydro-Shears' Forming at High Angles to σ1 in Foliated Mélange Matrix
No full textIncrementally developed slickenfibers — Geological record of repeating low stress-drop seismic events?
No full textAn accretionary mélange of Triassic age ocean floor sediments exposed in the Chrystalls Beach Complex, South Island, New Zealand, comprises competent sandstone and chert phacoids set in a cleaved mudstone matrix, deformed in a continuous–discontinuous style at subgreenschist conditions. Deformation structures include a pervasive anastomosing fault–fracture mesh of multiple shearing surfaces, subparallel to cleavage, coated with incrementally developed quartz–calcite slickenfibers. Microstructural observations reveal slickenfiber growth by ‘crack-seal’ shear slip increments of 10–100 μm, with incremental slip transfer of the same order accommodated by opening of extension fractures that link en echelon slip surfaces. Individual slip surfaces can be traced for meters to tens of meters so that the ratio of average slip, u, to potential rupture length, L, predominantly lies within the range, 10− 6 < u/L < 10− 5, characteristic of microearthquakes obeying ‘constant stress-drop’ scaling with a low stress-drop Δτ ~ 30 kPa, typical of low frequency earthquakes. The host-rock assemblage, metamorphic environment, inference of near-lithostatic fluid overpressures, low stress-drop and mixed continuous–discontinuous shearing, resemble conditions and characteristics of low frequency earthquakes as identified within the seismic signals recorded during episodic tremor and slow slip events, at the downdip end of the seismogenic subduction thrust interface and within accretionary prisms
A 2 h periodic variation in the low-mass X-ray binary Ser X-1
No full textSpectroscopy of the low-mass X-ray binary Ser X-1 using the Gran Telescopio Canarias have revealed a ?2 h periodic variability that is present in the three strongest emission lines. We tentatively interpret this variability as due to orbital motion, making it the first indication of the orbital period of Ser X-1. Together with the fact that the emission lines are remarkably narrow, but still resolved, we show that a main-sequence K dwarf together with a canonical 1.4 M? neutron star gives a good description of the system. In this scenario, the most likely place for the emission lines to arise is the accretion disc, instead of a localized region in the binary (such as the irradiated surface or the stream-impact point), and their narrowness is due instead to the low inclination (?10°) of Ser X-1
Review of the book Unbegrenzte moglichkeiten: Amerikanisierung in Deutschland und Frankreich (1900-1933) by Egbert Klautke
No full textDr. Jeff R. Schutts (Douglas College) reviews the book Unbegrenzte Moglichkeiten: Amerikanisierung in Deutschland und Frankreich (1900-1933) by Egbert Klautke (2005).Final article published
Letter from R. H. Ford to Commissioner of Indian Affairs, 1860
No full textR. H. Ford (letter author) is the brother of Henry L. Ford. The letter asks if the recently deceased Henry L. Ford was due anything from the government, which would be left to his father, William Ford
Papers of R H Horne
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/69212R.H. "Orion" Horne: Syllabus of Three Lectures on the Undeveloped Characters in Shakespeare's Plays by R.H. Horne, author of "Orion", "Cosmo de Medici" and "Death of Marlowe", etc. Leaflet showing contents of each of the three lectures. On verso, a note by Horne explaining that these lectures had been given at the Manchester Athenuem, the Literary and Scientific Institute, Marylebone, and at the Mechanics Institute, Liverpool. This leaflet is folded in with handwritten expositions (probably lectures): 1. The Bible, 31 pp. 2. Gems form Auriel (Henri Frederico Auriel, 1821-1881), 5 pp. 3. Some illustrations of Shakespeare's Art, 20 pp.113896
Acquisition: [1989.0151] "Papers of R H Horne
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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