Modeling regional landslide susceptibility using dynamic soil moisture profiles

A landslide susceptibility mapping study was performed using dynamic hillslope hydrology. The modified infinite slope stability model that directly includes vadose zone soil moisture (SM) was applied at Cleveland Corral, California, US and Krishnabhir, Dhading, Nepal. The variable infiltration capacity (VIC-3L) model simulated vadose zone soil moisture and the wetness index hydrologic model simulated groundwater (GW). The GW model predictions had a 75% NASH-Sutcliffe efficiency when compared to California’s in-situ GW measurements. The model performed best during the wet season. Using predicted GW and VIC-3L vadose zone SM, the developed landslide susceptibility maps showed very good agreement with mapped landslides at each study region. Previous quasi-dynamic model predictions of Nepal’s hazardous areas during extreme rainfall events were enhanced to improve the spatial characterization and provide the timing of hazardous conditions.     

THE MULTIPLICITY PRINCIPLE IN MODERN REMOTE SENSING METHODS AND ITS APPLICATION TO AGRICULTURAL IMAGE INTERPRETATION

The authors elaborate upon the “multiplicity principle” in remote sensing, i.e., the need for repeated imaging at a variety of scales, spatial resolutions, spectral bands, and times of imaging in order to attain the maximum information possible. They then explore the ways it can be applied in agricultural research, through two different image comparison and interpretation strategies. A detailed example is presented of the use of a multitemporal imaging strategy for the recognition of several agricultural crops from false color composite imagery. Translated by Edward Torrey, Alexandria, VA 22308 from: G. V. Dobrovol'skiy and V. L. Andronikov, eds., Aerokosmicheskiye metody v pochvo-vedenii i ikh ispol'zovaniye v sel'skom khozyaystve: sbornik nauchnykh trudov [Remote Sensing Methods in Soil Science and Their Utilization in Agriculture: A Collection of Scientific Works]. Moscow: Nauka, 1990, pp. 47-55.     

Comprehensive studies in the Black Sea and the Sea of Azov in the Summer of 2012

The shelf zones of the Black Sea, Taman Bay, and the Sea of Azov are currently subjected to gross load related to the impact of invasive species, large-scale construction activities near the coast, intensive recreation activity, water pollution in large cities and ports, active navigation, unreasonable coastal arrangement, and dam construction. Another factor substantially affecting the composition of bottom sediments and, thus, the benthos environment is the terrigenous material carried by rivers in the course of catastrophic overflows. An example is the Kubansk flood in 2012, which significantly affected the sea coast near Novorossiysk, Gelendzhik, and Divnomorsk. The intensive onshore dumping results in the delivery of abundant allochthonous material, bottom silting causing changes in the dominants in the benthos associations, a decrease in the photic layer and the death of the phytobenthos, and also debris formation at the bottom. Debris can play the role of artificial reefs contributory for the formation of periphytic biocoenoses.     

A note on wave action conservation in a dissipative current wave motion

We consider steady, slowly varying water waves propagating on a steady current over a gently sloping bed, so-called current depth refraction. All expressions are correct to second order in wave amplitude. Formulating the energy equation for the fluctuating motion in terms of wave action (wave energy divided by intrinsic angular frequency) results in an expression, where the dissipative term is strikingly similar to wave action itself. It is simply the ‘extra’ dissipation (per unit area) caused by the fluctuating motion (i.e. total dissipation minus the effect of current acting on total mean bed shear stress) divided by the intrinsic angular frequency. We call it ‘wave action dissipation’. An inconsistency in Phillips' (1977) book is pointed out. A new formula for the calculation of wave amplitudes along rays is set forth.     

Resistance of Lophelia pertusa to coverage by sediment and petroleum drill cuttings

In laboratory experiments, the cold-water coral Lophelia pertusa was exposed to settling particles. The effects of reef sediment, petroleum drill cuttings and a mix of both, on the development of anoxia at the coral surface were studied using O₂, pH and H₂S microsensors and by assessing coral polyp mortality. Due to the branching morphology of L. pertusa and the release of coral mucus, accumulation rates of settling material on coral branches were low. Microsensors detected H₂S production in only a few samples, and sulfate reduction rates of natural reef sediment slurries were low (<0.3 nmol S cm⁻³ d⁻¹). While the exposure to sediment clearly reduced the coral’s accessibility to oxygen, L. pertusa tolerated both partial low-oxygen and anoxic conditions without any visible detrimental short-term effect, such as tissue damage or death. However, complete burial of coral branches for >24 h in reef sediment resulted in suffocation.     

Pyroxenite xenoliths from an alkali trachybasalt in the Glen Innes area,northeastern New South Wales

Pyroxenite xenoliths are relatively common in an alkali trachybasalt in the Glen Innes area in northeastern New South Wales where they coexist with peridotite xenoliths, probably lherzolitic. The pyroxenites vary widely in modal composition. Several pyroxenite xenoliths are characterised by megacrystals of subcalcic clinopyroxene and enstatite, the former comprising a unique group of high pressure pyroxenes in which exsolution of orthopyroxene has proceeded on a megascopic scale. Garnet is absent from all mineral assemblages. Mineralogical and experimental data suggest that the subcalcic clinopyroxene and orthopyroxene megacrystals equilibrated initially at temperatures and pressures of the order of 1350–1450° C and 10–23 kb respectively. The most common xenoliths, namely diopsideorthopyroxene assemblages in which there is evidence of subsolidus annealing, equilibrated at comparable pressures but a significantly lower temperatures (ca. 1000° C). It is suggested that the pyroxenites and associated peridotite xenoliths are samples of essentially unmodified layered upper mantle.     

Geomorphological Holocene events as deduced from lithological records of the fluvial basins of Dauria

A conjugate analysis of the processes of morphogenesis and sedimentation within small fluvial basins of Dauria revealed a rhythmic character of change of the Holocene processes which are combined into cycles of a different hierarchical level. It is shown that each cycle begins with an extreme phase of intense fluvial drift and delivery of matter from the system. The fluvial horizons comprise the lower part of deposits of the Holocene macrocycle in the Vesnyanka pad’ (a valley without a permanent watercourse). A disastrous fluvial drift was recorded repeatedly for the period 7–8.5 cal. ka and at the transition time from the Atlantic to Subboreal time. A normal zonal phase of integration of matter within the basins is exhibited by buried humus horizons of soils which give clear evidence of 1800-year cycles. A regional development in Dauria is recorded for the soils with the age of about 8, 6.4 and 4.6 as well as 1.2–1.4 cal. ka. The upper part of the deposits of each cycle is characterized by aeolian horizons of extreme arid phases. The profiles of proluvial trails are indicative of 130-year cycles. Based on results from studying buried soils, data of pollen analysis and radiocarbon dating of the deposits, we determined an enhancement in climate aridization for the last 10 ka and, in general, a decreased of the sedimentation and morphogenesis rate.     

Modelling aspects of structures isolated with the frictional pendulum system

Different modelling aspects of structures isolated using the frictional pendulum system and subjected to earthquake ground motions are studied herein. Although the vertical dynamics of these structures is given special emphasis, other effects such as large isolator deformations and bidirectional input motion are also considered. Different structural models of the FPS are developed and tested for single-storey structures and a real four-storey building frame; among them, an ‘exact’ formulation of the FPS force–deformation constitutive relationship is presented. Results show that global building responses can be computed within 20 per cent error in the mean using a simplified model that ignores the vertical motion of the building; however, structural member deformations and forces need to be computed using a model that considers such motion. This is of particular importance when there exist correlation between the horizontal and vertical components of ground motion. Further, a physical model of the FPS is introduced and used to determine the response of a real four-storey frame, including uplift and downward impact. Results from this analysis show that local column responses may vary substantially depending on the stiffness of the isolation storey and the presence of a mass at the isolation level. Such mass is capable of filtering the large increase in column shear that results from the impact of the structure after uplift. Uplift occurs at several instants of the response of the structure considered, leading to an increase in column base shear as large as 3 times the shear obtained by ignoring the vertical dynamics of the building. © 1998 John Wiley & Sons, Ltd.     

Trace elements as indicators of the physicochemical conditions of mineral formation in hydrothermal sulfide systems

The three-mode distribution of trace-element (TE) concentrations is observed in accordance with three main forms of TE occurrence in mineral: structural, surficial, and phase (native TE phases). Minerals of hydrothermally synthesized pyrite–pyrrhotite–magnetite–greenockite assemblage in the presence of Au and Mn are studied. Discrimination of modes is made, using the method of statistical sample of analytical data for single crystals (SSADSC), which is based on the postulate that individual crystals can contain predominantly one of possible forms. This is supported by study of Cd modes of occurrence by element thermorelease atomic-absorption spectrometry. X-ray photoelectron spectroscopy and atomic-force microscopy were used to examine the surficial TE forms. It has been confirmed that the dependence of the TE content on the crystal size in the sample is mainly due to surficial nonautonomous phases absorbing TEs. The effect of correspondence of chemical-component forms on the surfaces of coexisting minerals is also corroborated. This phenomenon is not related to the mutual contamination of phases but is due to the induction of the corresponding states of chemical forms in coexisting nonautonomous phases. It is possible to obtain true coefficients of interface distribution, characterizing structural TE impurities. These coefficients differ strongly from apparent distribution coefficients calculated from the bulk contents of impurities, except for Mn in pyrrhotite and magnetite, where its structural mode is predominant. The results obtained show that TEs can be used as quantitative geochemical indicators, which help to obtain correct information about the parameters of mineral formation and TE contents in the fluid phase.