Hybrid toponyms of Panama as a reflection of toponymic bilingualism

The article presents evidence of a comprehensive linguistic analysis of the toponymy of Panama. The relevance of the topic is due to the fragmented research of Panamanian toponymy and the need for a comprehensive study of socio-historical and linguocultural factors in the formation of the Panamanian toponymicon. The hypothesis of the article is as follows: toponymy of Panama has a unique heterogeneous and polystrate character, semiotically determined by historical facts, ethnic composition of the population, natural conditions of the country and migration processes. Maps, GoogleMaps, GeoNames electronic systems were used as materials and tools. It was found that Hispanic geographic names make up the largest percentage in comparison with autochthonous toponyms and hybrid (blended) toponyms. The authors identified Spanish-Indian and Spanish-English blended place names. It is substantiated that Panama is a unique area of ​​functioning of the general Spanish toponymic vocabulary. Historical and cultural events in the country were reflected in toponymy, capturing the topographic relief, including metaphorically perceived, names of first settlers, names of famous Panamanian personalities, perception of topographic objects at various stages of the country's development, influence of English language, which together form the toponymic dominants of the Panamanian society, heterogeneity and unique hybrid Indian-Spanish-English character of toponymicon, on the basis of which the term “toponymic multilinguism” is proposed.

KINNEYIA-TYPE WRINKLE STRUCTURES ON SANDSTONE BEDS: NOT MICROBIALLY INDUCED BUT DEFORMATION FEATURES CAUSED BY SYNSEDIMENTARY EARTHQUAKES

ABSTRACT A category of wrinkle structures, often termed Kinneyia structure or Runzel marks, comprises bedding plane features consisting typically of anastomosing, low-relief, flat-topped ridges with intervening depressions. Topographic relief is usually less than a millimeter. They are locally common on the upper surfaces of fine- to medium-grained sandstone beds interbedded with mudstone deposited in offshore settings, especially in Precambrian and lower Paleozoic strata but as young as Cretaceous. For more than the last two decades these wrinkle structures have been widely regarded as due to microbial mats, and have been taken as evidence for dominance in the Proterozoic of microbially stabilized sediment and, in the Phanerozoic, a matground marine benthic ecology which gradually gave way to a mixground ecology. The detailed morphology and cross-cutting relationships demonstrated by a range of specimens of Proterozoic, Cambrian, and Silurian age, however, cast this interpretation into doubt. The relationship between the wrinkled surface and bioclasts such as shells and both prior- and later-formed scour surfaces, and horizontal and vertical burrows show that these wrinkles did not develop due to the surface topography of microbial mats or compaction of microbial mats during burial, but instead formed at the top of a sand bed at the interface with an overlying layer of mud. Deformation is ascribed to vibration from low-magnitude earthquakes. The presence in some units of small-scale sedimentary dikelets and crack arrays that formed later after some stiffening, along with locally associated seismites and other evidence for nearby faulting, show that syndepositional tectonic activity was not unexpected and support the interpretation that this category of wrinkle structures is a type of seismite.

Research on Micro-terrain Classification of Transmission Line Galloping

Micro-terrain and micro-weather have an important impact on transmission line galloping. In order to carry out galloping prediction of micro-terrain, the classification of galloping micro-terrain is studied in this work. Firstly, we collect historical data of 1537 galloping points from the State Grid Corporation of China, and select 208 galloping points located in the micro-terrain area by analyzing the altitude and the topographic relief characteristics around each galloping point. Then the galloping micro-terrain types are extracted by Empirical Orthogonal Function method, the first four spatial modes of galloping micro-terrain are the windward slope of east-west mountain area, the windward slope of north-south mountain area, the independent hill, and the saddle back of mountain/hill. Finally, the regional characteristics of typical micro-terrain are analyzed according to the actual lines.

Alpine relief limited by glacial occupation time

Glaciers exert a major control on the shape of mountain topography. They tend to reduce relief above and scour troughs below the equilibrium line altitude (ELA). While many studies report this dichotomy, relief-limiting effects are controversial due to difficulties in quantifying key factors such as the initial topography, the timing of glacial occupancy, or rock uplift counteracting glacial erosion. Consequently, effectivity and degree of glacial erosion remain ambiguous. In geologically and climatically well-investigated parts of the European Central Alps, our calculation of glacial occupation time (GOT) from Quaternary ELA variations allows the quantification of gradual topographic modifications generated by the cumulative impact of cirque erosion over the Quaternary. We show that under low uplift, relief is effectively limited by glacial and periglacial headwall retreat, leading to a decline in topographic relief as GOT increases. Conversely, higher uplift rates seem to induce more persistent valley glaciation, triggering a positive feedback loop in which steep slopes are protected against erosion and relief increases.

Nunataks as barriers to ice flow: implications for palaeo ice-sheet reconstructions

Numerical models predict that discharge from the polar ice sheets will become the largest contributor to sea level rise over the coming centuries. However, the predicted amount of ice discharge and associated thinning depends on how well ice sheet models reproduce glaciological processes, such as ice flow in regions of large topographic relief, where ice flows around bedrock summits (i.e. nunataks) and through outlet glaciers. The ability of ice sheet models to capture long-term ice loss is best tested by comparing model simulations against geological data. A benchmark for such models is ice surface elevation change, which has been constrained empirically at nunataks and along margins of outlet glaciers using cosmogenic exposure dating. However, the usefulness of this approach in quantifying ice sheet thinning relies on how well such records represent changes in regional ice surface elevation. Here we examine how ice surface elevations respond to the presence of obstacles that create large topographic relief by modeling ice flow around and between idealised nunataks during periods of imposed ice sheet thinning. We found that, for realistic Antarctic conditions, a single nunatak could exert an impact on ice thickness over 20 km away from its summit, with its most prominent effect being a local increase (decrease) of the ice surface elevation of hundreds of metres upstream (downstream) of the obstacle. A direct consequence of this differential surface response for cosmogenic exposure dating was a delay in the time of bedrock exposure upstream relative to downstream of a nunatak. A nunatak elongated transverse to ice flow, with a wide subglacial continuation, was able to increase ice retention and therefore impose steeper ice surface gradients, while efficient ice drainage through outlet glaciers alleviated the differential response. Such differences, however, are not typically captured by continent-wide ice sheet models due to their coarse grid resolutions. This appears to be a key reason why models overestimate ice-sheet surface elevations and underestimate the pace of ice sheet melt contributing to sea level rise compared to empirical reconstructions. We conclude that a model grid refinement over complex topography and information about sample position relative to ice flow near the nunatak are necessary to improve data-model comparisons of ice surface elevation, and therefore the ability of models to simulate ice discharge in regions of large topographic relief.

Region-by-Region Registration Combining Feature-Based and Optical Flow Methods for Remote Sensing Images

While geometric registration has been studied in remote sensing community for many decades, successful cases are rare, which register images allowing for local inconsistency deformation caused by topographic relief. Toward this end, a region-by-region registration combining the feature-based and optical flow methods is proposed. The proposed framework establishes on the calculation of pixel-wise displacement and mosaic of displacement fields. Concretely, the initial displacement fields for a pair of images are calculated by the block-weighted projective model and Brox optical flow estimation, respectively in the flat- and complex-terrain regions. The abnormal displacements resulting from the sensitivity of optical flow in the land use or land cover changes, are adaptively detected and corrected by the weighted Taylor expansion. Subsequently, the displacement fields are mosaicked seamlessly for subsequent steps. Experimental results show that the proposed method outperforms comparative algorithms, achieving the highest registration accuracy qualitatively and quantitatively.

Growing topography due to contrasting rock types in a tectonically dead landscape

Many mountain ranges survive in a phase of erosional decay for millions of years following the cessation of tectonic activity. Landscape dynamics in these post-orogenic settings have long puzzled geologists due to the expectation that topographic relief should decline with time. Our understanding of how denudation rates, crustal dynamics, bedrock erodibility, climate, and mantle-driven processes interact to dictate the persistence of relief in the absence of ongoing tectonics is incomplete. Here we explore how lateral variations in rock type, ranging from resistant quartzites to less resistant schists and phyllites, and up to the least resistant gneisses and granitic rocks, have affected rates and patterns of denudation and topographic forms in a humid subtropical, high-relief post-orogenic landscape in Brazil where active tectonics ended hundreds of millions of years ago. We show that catchment-averaged denudation rates are negatively correlated with mean values of topographic relief, channel steepness and modern precipitation rates. Denudation instead correlates with inferred bedrock strength, with resistant rocks denuding more slowly relative to more erodible rock units, and the efficiency of fluvial erosion varies primarily due to these bedrock differences. Variations in erodibility continue to drive contrasts in rates of denudation in a tectonically inactive landscape evolving for hundreds of millions of years, suggesting that equilibrium is not a natural attractor state and that relief continues to grow through time. Over the long timescales of post-orogenic development, exposure at the surface of rock types with differential erodibility can become a dominant control on landscape dynamics by producing spatial variations in geomorphic processes and rates, promoting the survival of relief and determining spatial differences in erosional response timescales long after cessation of mountain building.

Inverse Modeling of Earthquake Source Properties Constrained by Pseudotachylite Surface Roughness

<p>Under high rates of coseismic slip, frictional melt may be generated at the shear zone potentially altering the dynamics and rendering classical rate-and-state friction laws ineffective. Pseudotachylytes (solidified frictional melt) created in laboratories and found in natural fault zones thus provide thermal and mechanical information critical to the study of dynamic shear zone processes, including thermal runaway, stress drop, and viscous braking. While extensive geochemical and mineralogical evidence has suggested the occurrence of disequilibrium melting during pseudotachylite generation, few studies have leveraged it to resolve the kinematics of co-seismic slip.</p><p>In this study, we optimize the kinematic parameters of the regularized Yoffe source function using the topographic relief of a pseudotachylyte/wall rock surface in combination with a one-dimensional fluid-mechanical-thermal finite element model. The model consists of solving a two-phase moving boundary problem with an internal heat source constrained by the slip kinematics of the Yoffe function in tandem with the Couette flow problem as an approximation to the shearing of the viscous melt. The topographic relief data come from a pseudotachylyte-bearing fault within the Gole Larghe fault zone, Italy measured using high-resolution X-ray tomography. On this fault surface, biotites are ~260 (±100) micron lower than the mean surface height as a result of preferential melting associated with a lower fusion temperature than quartz or feldspar. Using Monte Carlo sampling of the relief data distribution and Bayesian optimization, we optimize the kinematic parameters of the regularized Yoffe functions and resolve the statistics of shear stress evolution.</p><p>Our preliminary results show that the displacement-averaged shear stress in frictional melt ranges from 2 to 7 MPa with a mean value of 5.5 MPa. This is much smaller than estimates based on pseudotachylyte thickness and laboratory experiments, indicating a more complete stress drop than previously thought. The optimal Yoffe source functions have a mean total rise time of ~4 seconds, which is longer than that inferred from scaling laws. Simulations are ongoing and we look forward to interpreting the results in the context of source properties, source models, and energy partitioning for pseudotachylyte-bearing faults.</p>