Environmental influences on landslide activity: Almora Bypass,Kumaun Lesser Himalaya

Landslides are self-organizing and self-referenced systems. The conditions which lead to their emergence along Himalayan highways are not the same as those which govern their subsequent evolution. Landslides originate at sites which differ from average conditions by having significantly higher, steeper roadcuts, carved into steeper hillsides, with more finely bedded but less steeply dipping rocks, and fewer trees upslope. These variables do not correlate with measures of landslide size. Landslide morphometric variables correlate with other landslide variables and with few external factors. The system exhibits independence (autopoiesis) from its environment. Additionally, landslides dominated by rock-mechanical processes tend to produce lower angle outfalls from higher, north-facing, roadcuts than those dominated by soil-mechanical processes which are associated with greater depths of below-soil regolith. However, the outfall volumes produced by the landslides of different type are similar. These findings are generated from statistical (correlation/T-test/stepwise discriminant) analyses of data produced by a field survey of average environmental conditions, and the morphometry and environmental contexts of 88 landslides, on 7.6 km of the Almora Bypass.     

The prehistory and palaeogeography of the great Indian desert : Bridget Allchin, Andrew Goudie, and Karunakara Hegde. Academic Press, London/New York/San Francisco, 1978, 370 pp., 73 figs., 85 tables, 12 plates. Bibliography, Index, £25/-, U.S. $48.90

Seismic reflection profiles (3.5 kHz) were obtained along more than 3500 km of shiptrack in Lake Superior within the last 2 yr. The acoustic character of profiles is categorized as: (I) a single, strong reflector at the lake floor, (II) a thick, acoustically transparent layer overlying a strong reflector, and (III) relatively thick sediment with internal acoustic reflectors. These profiles, in conjunction with sediment cores from the area, reveal that varved glacial-lacustrine sediment settled out preferentially in a trough between Isle Royale and the north shore, and to a lesser extent in other topographic depressions; bottom currents generated by storm waves prevent clay accumulation on till or bedrock in the open lake wherever the bottom is shallower than 100 m; bottom currents prevent deposition or erode bottom sediment in certain deep-water (> 200 m) valleys; and lacustrine sediment is disturbed by creep or slumping off Grand Portage, Minnesota, and by other processes such as dewatering in many other areas. These factors complicate sedimentation in Lake Superior, and must be considered when investigating any aspect of the lake sediment.     

Erosion of strip-mine dumps in la salle county,illinois: Preliminary results

Direct measurement of slope retreat on three unvegetated slope profiles on unmodified, pre-1939, strip-mine dumps revealed average ground losses ranging from 29 to 33 mm/year. Measured ground losses are twice those estimated from the Universal Soil Loss Equation. Slope length seems less significant than frost action in influencing erosion on these slopes.     

Geography and general system theory,philosophical homologies and current practice

General system science, like geography, is an integrative discipline that spans the divide between the physical and social sciences. Geography, like general system science, seeks to examine the universe of observation as a functioning whole and attempts to study together the things other disciplines study separately. However, within both geography and the system sciences at large, there are many different philosophies and methodologies. A special attribute of the general system approach is an explicit adoption of an organismic rather than a mechanistic world view. This has caused general system practitioners to develop theory in more bioscientific areas of concern such as growth, hierarchical organisation and the theory of evolution. To date, much of the systems science in geography has preferred the static, mechanistic ethos of systems analysis and systems engineering. However, general system science's concern with historic processes and the dynamic self-determined relationships between systems structure, functioning and selfcreation may be more appropriate to geographical research. A search is made for general system methodologies in current geographical research and for particular applications of aspects of the new general systems theory of evolution and theory of systems attractors as defined by Ilya Prigogine and Erich Jantsch to geography.Today, we seem to be at the tip of an iceberg of scientific change... Every discipline is in the midst of a revolution... What is exciting about this theoretical chaos is not that each discipline will emerge with a new paradigm to guide future investigations but that a new grand paradigm may be forming, one that will integrate all structure and processes from the farthest reaches of the Universe to the reasonances of subatomic particles. The Grand Paradigm is somewhere in the future and we may live to see it THEISEN, (1981, p. 758).     

A finite element–spherical harmonics model for radiative transfer in inhomogeneous clouds: Part I. The EVENT model

We present a new numerical radiative transfer model for application to solar radiation transport in three-dimensional (3D) cloudy atmospheres. The code uses the finite element–spherical harmonics (FE–P_N) approximation to solve the second-order even-parity form of the transport equation. It is validated by comparison with solutions from two well-established, deterministic radiative transfer models, the one-dimensional (1D) DISORT code and the spherical harmonics discrete ordinates method (SHDOM). The cases solved show generally good agreement, but also reveal some differences. EVEn-parity Neutral particle Transport (EVENT) is very efficient at performing 1D calculations quickly and, even for quite high angular resolutions, is faster. EVENT also has a competitive speed for the simpler, less-heterogeneous multidimensional cases but it is slower than SHDOM for more variable cases. However, there is significant potential to improve the performance of EVENT; it has not yet been optimised for speed and, as such, is not a finished product. Even as it is, EVENT could be used to produce fast, lower-resolution estimates for applications where this would be sufficient, or at lower-spatial resolutions with partial homogenisation.Another difference between the models is that the SHDOM algorithm is designed for small-scale inhomogeneous cloud fields in which the grid spacing is comparable to the mean free path. Problems arise from the use of larger grid cell optical depths, with an increase in the number of iterations required and a lack of flux conservation. Neither of the models is specifically constrained to conserve flux, but the conservation of flux gives an indication of the accuracy of the solution. Increasing the spatial and angular resolution can improve the accuracy but this is not always possible for very large 3D scenes. The grid-point method of property definition in SHDOM means that it performs best for cases with a continuous variation in extinction as this avoids discontinuities in the source function. The finite clouds used in our tests have sharp boundaries that are easily defined in EVENT but the difficulties caused by these in SHDOM are evident in excesses of up to 10 fluxes.The EVENT mesh resolution is determined by the local optical depth; it has no problem in dense areas but has more trouble in coping with voids or optically thin regions. These conditions are easily handled in SHDOM through streaming of photons along discrete ordinates but EVENT must implement methods such as a ray-tracing algorithm. Cases with extreme values of the extinction coefficient are probably best avoided with EVENT, but slightly larger-scale cases with greater optical depths, not suitable for SHDOM, may be solved more easily. These factors should be considered when selecting the most appropriate method for a particular application.     

Geographically distributed hybrid testing & collaboration between geotechnical centrifuge and structures laboratories

Distributed Hybrid Testing (DHT) is an experimental technique designed to capitalise on advances in modern networking infrastructure to overcome traditional laboratory capacity limitations. By coupling the heterogeneous test apparatus and computational resources of geographically distributed laboratories, DHT provides the means to take on complex, multi-disciplinary challenges with new forms of communication and collaboration. To introduce the opportunity and practicability afforded by DHT, here an exemplar multi-site test is addressed in which a dedicated fibre network and suite of custom software is used to connect the geotechnical centrifuge at the University of Cambridge with a variety of structural dynamics loading apparatus at the University of Oxford and the University of Bristol. While centrifuge time-scaling prevents real-time rates of loading in this test, such experiments may be used to gain valuable insights into physical phenomena, test procedure and accuracy. These and other related experiments have led to the development of the real-time DHT technique and the creation of a flexible framework that aims to facilitate future distributed tests within the UK and beyond. As a further example, a real-time DHT experiment between structural labs using this framework for testing across the Internet is also presented.     

“Grey swan” storm surges pose a greater coastal flood hazard than climate change

Ocean Dynamics - In this paper, we show that over the next few decades, the natural variability of mid-latitude storm systems is likely to be a more important driver of coastal extreme sea levels...     

A threatened world city: the benefits of protecting London from the sea

This paper describes the options appraisal undertaken in the UK within the major TE2100 project to investigate the future of protecting London from flooding from the sea. An economic analysis, within a Benefit-Cost framework complemented by Multi-Criteria Analysis, shows that improving the existing flood defences and, in 2070, constructing a new Thames Barrier downstream from the existing one are the “front runner” options for tackling the increase in flood risk that is anticipated in the future. Both sensitivity and scenario analysis have little effect on option choice. Uncertainties inevitably remain, however, when looking so far ahead, but it is clear that continuing to protect this area from the sea is highly cost-beneficial. Also the very high standard of protection now, and the robustness of the existing flood defence assets, mean that major new interventions will not be needed for some time (i.e. until c. 2070). We therefore have time to monitor the situation, carefully plan measures to maintain and enhance the existing defences, and to seek to restrain the growth of risk in the Estuary and in London through carefully designed and implemented resilience-building flood plain management measures. Rather than having to rush to new engineering works, because we have not anticipated what is needed but are forced to respond hastily to a “crisis” situation, the adaptive approach that is now possible is a key legacy of the TE2100 project.     

Understanding a coastal flood event: the 10th March 2008 storm surge event in the Solent, UK

Extreme sea-level events (e.g. caused by storm surges) can cause coastal flooding, and considerable disruption and damage. To understand the impacts or hazards expected by different sea levels, waves and defence failures, it is useful to monitor and analyse coastal flood events, including generating numerical simulations of floodplain inundation. Ideally, any such modelling should be calibrated and validated using information recorded during real events, which can also add plausibility to synthetic flood event simulations. However, such data are rarely compiled for coastal floods. This paper demonstrates the capture of such a flood event dataset, and its integration with defence and floodplain modelling to reconstruct, archive and better understand the regional impacts of the event. The case-study event comprised a significant storm surge, high tide and waves in the English Channel on 10 March 2008, which resulted in flooding in at least 37 distinct areas across the Solent, UK (mainly due to overflow and outflanking of defences). The land area flooded may have exceeded 7 km², with the breaching of a shingle barrier at Selsey contributing to up to 90 % of this area. Whilst sea floods are common in the Solent, this is the first regional dataset on flood extent. The compilation of data for the validation of coastal inundation modelling is discussed, and the implications for the analysis of future coastal flooding threats to population, business and infrastructure in the region.