[1] The transpressional boundary between the Australian and Pacific plates in the central South Island of New Zealand comprises the Alpine Fault and a broad region of distributed strain concentrated in the Southern Alps but encompassing regions further to the east, including the northwest Canterbury Plains. Low to moderate levels of seismicity (e.g., 2 > M 5 events since 1974 and 2 > M 4.0 in 2009) and Holocene sediments offset or disrupted along rare exposed active fault segments are evidence for ongoing tectonism in the northwest plains, the surface topography of which is remarkably flat and even. Because the geology underlying the late Quaternary alluvial fan deposits that carpet most of the plains is not established, the detailed tectonic evolution of this region and the potential for larger earthquakes is only poorly understood. To address these issues, we have processed and interpreted high-resolution (2.5 m subsurface sampling interval) seismic data acquired along lines strategically located relative to extensive rock exposures to the north, west, and southwest and rare exposures to the east. Geological information provided by these rock exposures offer important constraints on the interpretation of the seismic data. The processed seismic reflection sections image a variably thick layer of generally undisturbed younger (i.e., < 24 ka) Quaternary alluvial sediments unconformably overlying an older (>59 ka) Quaternary sedimentary sequence that shows evidence of moderate faulting and folding during and subsequent to deposition. These Quaternary units are in unconformable contact with Late Cretaceous-Tertiary interbedded sedimentary and volcanic rocks that are highly faulted, folded, and tilted. The lowest imaged unit is largely reflection-free PermianTriassic basement rocks. Quaternary-age deformation has affected all the rocks underlying the younger alluvial sediments, and there is evidence for ongoing deformation. Eight primary and numerous secondary faults as well as a major anticlinal fold are revealed on the seismic sections. Folded sedimentary and volcanic units are observed in the hanging walls and footwalls of most faults. Five of the primary faults represent plausible extensions of mapped faults, three of which are active. The major anticlinal fold is the probable continuation of known active structure. A magnitude 7.1 earthquake occurred on 4 September 2010 near the southeastern edge of our study area. This predominantly right-lateral strike-slip event and numerous aftershocks (ten with magnitudes ≥5 within one week of the main event) highlight the primary message of our paper: that the generally flat and topographically featureless Canterbury Plains is underlain by a network of active faults that have the potential to generate significant earthquakes.

Plate boundary deformation creates a south-easterly advancing, repetitive structural pattern in Canterbury dominated by the propagation of northeast-striking thrust assemblages. This pattern is regularly segmented by east-striking faults inherited from reactivated Cretaceous normal faults. The more evolved and deeply exposed structures in the foothills of north Canterbury provide insights into the tectonic processes of the blind structures now emerging from under the northern and eastern Canterbury Plains, where thrust and strike-slip fault activity are closely linked. The east-striking faults separate relative motion between thrust segments and accommodate oblique transpressive shear. Early stages of thrust emergence are dominated by anticlinal growth and blind, or partially buried, thrusts and backthrusts. The east-striking transecting faults therefore record timing of coseismic episodes of uplift and shortening with variable horizontal to vertical ratios and displacement rates on the hidden adjacent thrusts. The Greendale and blind Port Hills faults, with their associated aftershock patterns, are compatible with this style.

No abstract

No abstract

In this paper, we describe a simple method for automatic detection of melanin spots in Atlantic salmon fillets. Melanin spots are visible dark spots that reduce the quality grade of the fillets. Atlantic salmon processing lines have several operations that involve manual quality evaluation of fillets. One such operation is the inspection of fillets to detect melanin spots. This inspection is labor intensive, and therefore desirable to automate. Two simple computer vision algorithms for melanin spot detection are presented. One algorithm operates on the red channel of RGB images and the second algorithm uses linear discriminant analysis (LDA) on all three RGB channels. A comparison between these two algorithms shows that, for most detection rates, using LDA gives a lower number of false-detections per fillet. We show that the melanin spot detection task can potentially be automated using computer vision.

No abstract

A new multispectral image context classification, which is based on a stochastic relaxation algorithm and Markov-Gibbs random field, is presented. The implementation of the relaxation algorithm is related to a form of optimization programming using annealing. The authors motivate a Bayesian context decision rule, and a Markov-Gibbs model for the original Landsat MSS (multispectral scanner) image is introduced, and then develop a new contextual classification algorithm, in which maximizing the posterior probability (MAP) is based on stochastic relaxation, an annealing optimization method. Finally, experimental results that are based on simulated and real multispectral remote sensing images to Fhow how classification accuracy is greatly improved are presented. The algorithm is highly parallel and exploits the equivalence between Gibbs distribution\ and Markov random fields (MRF).

No abstract