The oblique collision zone of Arabia-Eurasia is a seismically active region with complex crustal deformation patterns. While GPS measurements provide valuable data, their sparse distribution limits our understanding of the full extent of deformation. This study addresses this limitation by using a robust interpolation method for GPS velocity data in the collision zone. We utilized biharmonic splines to interpolate horizontal components of sparse GPS velocity data independently and in a coupled manner by altering Poisson ratio. This method is an effective means of interpolating sparse vector data in cases where deformation mechanics can be explained by elasticity principles. The interpolation process included fitting trends to the input data, calculating residuals, and analyzing them. The prediction process consisted of trend and spline fitting stages. We interpolate horizontal GPS velocities onto a standard geographic grid with a 30-minute interval, excluding data points with significant deviation. The data was partitioned into training and testing subsets, with the training set used for calibration and the testing set for evaluation of the interpolation method. Our analysis revealed an irregular spatial distribution of crustal movement. The northern component of the velocity field consistently points towards Eurasia and is greater than the eastern component. The amplitude of the northern component decreases from south to north and from west to east, indicating variations in deformation intensity. The eastern component exhibits a change in direction, moving westward in the western half of Iran and eastward in the eastern half, with a reversed trend in the north. This change in direction highlights the presence of solid blocks within the collision zone. Undeformed regions, major faults, convergence deformation, and compressing high-elevation regions are also observed in the collision zone. These findings provide a detailed picture of present-day crustal deformation in the Arabia-Eurasia collision zone, enhancing our understanding of the collision process.
Cut marks are striae accidentally produced by the contact made between the edge of a cutting tool and bone surfaces by anthropogenic activity, presenting evidence of hominin carcass processing and behaviour, butchery activities or diet. Post-depositional processes can cause the alteration (chemical or mechanical) of bones surfaces, changing their composition and causing the modification of bone surfaces. Previous research has addressed the problem of chemical alteration from a qualitative perspective, resulting in the loss of all diagnostic characteristics of the cut marks affected by these processes. Geometrics Morphometrics has led to great progress in the study of cut marks from a quantitative perspective and can be useful for the study of altered cut marks. In this study, an experiment was carried out in which 36 cut marks were reproduced and chemically altered. These marks were scanned and digitized before and after each phase of alteration. They were analyzed metrically as well as using Geometric Morphometrics, in order to study the evolution of modifications to cut mark morphology during the experiment. Results show clear morphological differences between the different phases of alteration with altered cut marks presenting a general tendency towards a decrease in both the width and depth over time. Research of this type opens up a new path for the study of the chemical alteration of cut marks, as well as other striae, through the application of Geometric Morphometrics.
Coastal communities face substantial risks from long-term sea level rise and decadal sea level variations, with the North Atlantic and U.S. East Coast being particularly vulnerable under changing climates. Employing a self-organizing map-based framework, we assess the North Atlantic sea level variability and predictability using 5000-year sea level anomalies (SLA) from two preindustrial control model simulations. Preferred transitions among patterns of variability are identified, revealing long-term predictability on decadal timescales related to shifts in Atlantic meridional overturning circulation phases. Combining this framework with model-analog techniques, we demonstrate prediction skill of large-scale SLA patterns and low-frequency coastal SLA variations comparable to that from initialized hindcasts. Moreover, additional short-term predictability is identified after the exclusion of low-frequency signals, which arises from slow gyre circulation adjustment triggered by the North Atlantic Oscillation-like stochastic variability. This study highlights the potential of machine learning to assess sources of predictability and to enable long-term climate prediction.
This paper describes analyses of avifauna from Levantine Late Pleistocene and Early Holocene sites at contrasting scales. We present avian osteological data at Shubayqa, in northeast Jordan, illustrating human-bird-environment interactions over 4000 years offering interpretation of environmental change on avifaunal communities and reorientation in the nature of multi-species relationships at a wetland environment. Comparisons to published avifaunal assemblages investigates bird-human relationships across a broader temporal and geographical span. During the Late Pleistocene and Early Holocene, some of our species gradually transitioned to agriculture. People hunted birds for subsistence but extensive evidence for the symbolic importance of birds suggests complex relationships between species. Avifaunal evidence, therefore, presents insights into two commonly suggested primary causes for the shift from hunter-foragers to agriculturalists – resource pressure and symbolic expression. In this paper, we investigate and try to clarify the relationship between humans and birds at this transitional period in human history, furthering discussions of the shift towards agriculture. We argue humans gradually modified the landscape but this was not a reactionary response to resource stress. Nevertheless, this resulted in the productivity of the landscape increasing and allowed further intensification. Feathers and talons of birds were used for millennia preceding the shift to agriculture and the increase in bird hunting towards the end of the Pleistocene cannot be explained by the increased role of birds in the symbolic realm. The evidence from the avifauna adds weight to the idea of ecological niche construction activities, as people invested in specific locations, increasing productivity of habitats, thus encouraging further investment within some environments.
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