Information Support Technology in Managing the Volga–Kama Cascade of Reservoirs

The paper presents the structure of information support technology and algorithms of the decision-making process in managing the Volga–Kama cascade of reservoirs, as well as the results of implementing into the operational practice of a technology for regulating reservoirs and the prospects of its use for solving water problems.     

Assessing the use of U–Th methods to determine the age of cold-water calcareous algae

Calcitic crusts of calcareous red algae could be suitable material for age determination of raised marine deposits and palaeothermometry at annual to sub-annual resolution. We examined the potential of U–Th dating of cold-water calcareous algae by analysing fossil specimens (n=10) from Kapp Ekholm (Svalbard) and recent specimens from Norway (n=3) and Scotland (n=1). After initial measurements using α-spectrometry, thermal ionisation mass spectrometry (TIMS) was used to study the material in more detail. Recent specimens contain 0.19–1.55 μg g⁻¹ U, and the measured (²³⁴U/²³⁸U) activity ratios vary between 1.12 and 1.30. Fossil specimens contain 1–168 μg g⁻¹ U, and display variable and highly elevated initial (²³⁴U/²³⁸U) activity ratios. In general, the TIMS results show increasing (²³⁴U/²³⁸U) activity ratios and concentrations of U and Th with increasing stratigraphic age. From this it is evident that marine calcareous red algae contain U in-vivo and they experience substantial post-mortem uptake of U. We conclude that direct U–Th dating of fossil calcareous algae from raised marine deposits is not viable without further geochemical understanding of the in-vivo uptake and post-depositional pathways of U and Th in such deposits. Despite the convincing open-system behaviour of the material, comparison with previously published chronostratigraphy from the site shows that the calcareous algae generally yield ages that are too old. This is in contrast to the expected result based on simple continuous post-mortem U accumulation and calls for a complex model comprising migration of U and multi-component addition of Th (detrital/colloidal) to explain the observed trends.     

Assessing the volumes of material discharged by Bezymyannyi Volcano during the 1955–2009 period

We present data on the volumes of material discharged during the main phases of the volcano’s recent activity from its start in October 1955 until December 2009. The amount of ash discharged onto the ground surface during the preculmination period (October 1955 to March 1956) is estimated as 400 million tons; the paroxysmal eruption of March 30, 1956 discharged more than 400 million tons, the volume of pyroclastic flows was estimated as 1416 million tons. The following estimates were obtained for the material discharged onto the ground surface for the period from 1956 to 2009. The weight of the lava cone that grew in the newly formed crater is 941 million tons, the deposits of pyroclastic flows weighed 491 million tons, and the ash weight was 117 million tons. Effusive activity was insignificant; the weight of the lava flows was ∼9.2 million tons. The amount of material erupted during the third phase is estimated as 1560 million tons. The mean annual discharge between April 1956 and December 2009 was 29 million tons. This figure is half that for the giant Klyuchevskoi volcano and six times larger than the mean discharge found for the 5000–5500 years of the existence of Bezymyannyi Volcano.     

Assessing interpolation error for space–time monitoring data

In Europe, since 1990, a survey on environmental monitoring has been taking place every 5 years, using moss samples to study the distribution of heavy metal concentration and assess contamination sources, resulting on the identification of statistical association of several heavy metal concentrations in mosses. With this work, we propose an extension of an existing spatio-temporal model, introduced in Høst et al. (JASA 90(431):853–861, 1995), allowing for prediction at unsampled locations of pollution data in the presence of covariates related to each country specificities, when separately modelling the spatial mean field, the spatial variance field and the space–time residual field. Moreover, this model allows to estimate an interpolation error, as an accuracy measure, derived dependently on the case study. For a validation purpose, a simulation study is conducted, showing that the use of the proposed model leads to more accurate prediction values. Results obtained by the proposed methodology for the most recent available survey, are compared with results obtained with no temporal information, namely when Ordinary Kriging, according to the definition in Cressie (Statistics for spatial data, Wiley, New York, 1993), is used to derive illustrative prediction maps based only on the most recent data. An exercise of cross-validation is performed relative to each of the scenarios considered and the average interpolation errors are presented. While assessing interpolation errors, we conclude that the monitoring specificities of each country and the information of preceding surveys allow for more accurate prediction results.     

Modeling Optimal Control of the Ecological–Socioeconomic System Water Body–Watershed: Case Study of the White Sea Region

Water Resources - A cognitive model of optimal control of an ecological–socioeconomic system water body–watershed for the case of the White Sea (Beloe more) and its watershed...     

Ecological–Geochemical Conditions of Surface Water and Groundwater and Estimation of the Anthropogenic Effect in the Basin of the Ganjiang River

Water Resources - Data of studies of 2013–2019 were used to assess the current environmental-geochemical conditions of surface water and groundwater in the basin of the Ganjiang River, the...     

Conditions for a steady ice sheet–ice shelf junction

This paper investigates the conditions under which a marine ice sheet may adopt a steady profile. The ice is treated as a linear viscous fluid caused to flow from a rigid base to and over water, treated as a denser but inviscid fluid. The solutions in the region around the point of flotation, or ‘transition’ zone, are calculated numerically. In-flow and out-flow conditions appropriate to ice sheet and ice shelf flow are applied at the ends of the transition zone and the rigid base is specified; the flow and steady free surfaces are determined as part of the solutions. The basal stress upstream, and the basal deflection downstream, of the flotation point are examined to determine which of these steady solutions satisfy ‘contact’ conditions that would prevent (i) the steady downstream basal deflection contacting the downstream base, and (ii) the upstream ice commencing to float in the event it was melted at the base. In the case that the upstream bed is allowed to slide, we find only one mass flux that satisfies the contact conditions. When no sliding is allowed at the bed, however, we find a range of mass fluxes satisfy the contact conditions. The effect of ‘backpressure’ on the solutions is investigated, and is found to have no affect on the qualitative behaviour of the junctions. To the extent that the numerical, linearly viscous treatment may be applied to the case of ice flowing out over the ocean, we conclude that when sliding is present, Weertman's ‘instability’ hypothesis holds.     

Laboratory Modeling of Aftershock Sequences: Stress Dependences of the Omori and Gutenberg–Richter Parameters

Izvestiya, Physics of the Solid Earth - Laboratory experiments on studying the aftershock regime are carried out on sandstone specimens at different levels of axial loading and uniform compression...     

Modeling the ML4.7 mainshock of the February–July 2001 earthquake sequence in Aegion, Greece

An earthquake sequence comprising almost 2000 events occurred in February–July 2001 on the southern coast of the Corinth Gulf.Several location methods were applied to 171 events recorded by the regional network PATNET. The unavailability of S-wave readings precluded from reliable depth determination. For the mainshock of April 8, M_L= 4.7, the depth varied from 0 to 20 km. The amplitude spectra of complete waveforms at three local stations (KER,SER, DES; epicentral distances 17, 26 and 56 km) were inverted between 0.1 and 0.2 Hz for double-couple focal mechanism and also for the depth. The optimum solution (strike 220°, dip 40°, rake ‒160°, and depth of 8 km) was validated by forward waveform modeling.Additionally, the mainshock depth was further supported by the P- and S-wave arrival times from the local short-period network CRLNET (Corinth Rift Laboratory).The scalar seismic moment was 2.5e15 Nm,and the moment rate function was successfully simulated by a triangle of the 0.5 second duration. This is equivalent to a 1–1.5 km fault length, and a static stress drop 2–6 MPa. This value is important for future strong ground motion simulation of damaging earthquakes in Aegion region, whose subevents may be modeled according to the studied event. The T axis of the mainshock (azimuth 176° and plunge 67°), is consistent with the regional direction of extension N10°. However, none of the nodal planes can be associated to an active structure seen at the surface. The relationship of this earthquake sequence with deeper faults (e.g. possible detachment at about 10 km) is also unclear.     

Assessing the possible effect of developing the Zelenodol’skoe groundwater deposit on the ecosystems of the Volzhsko–Kamskii Reserve: Contradictions and compromises

The effect of maximal design water extraction on groundwater levels, lake budgets, and vegetation in the Volzhsko–Kamskii Reserve was assessed with the use of a hydrodynamic scheme of interaction between groundwater and surface water, specially developed for the territory of the Zelenodol’skoe Fresh Groundwater Deposit and mathematical simulation. The first stage of deposit development was proved to have no such effect. A scheme of the further development of the deposit by the results of environmental monitoring is recommended.     

Analytical Description of the Near Planetary Bow Shock Based on Gas-Dynamic and Magneto-Gas–Dynamic Modeling for the Magnetic Field Parallel and Perpendicular to the Plasma Flow

Geomagnetism and Aeronomy - An analytical semiempirical model of the bow shock based on theoretical MGD calculations, accurate analytical solutions, and experimental data continues to be developed....     

Late Pleistocene and Holocene activity of the Atacazo–Ninahuilca Volcanic Complex (Ecuador)

The Atacazo–Ninahuilca Volcanic Complex (ANVC) is located in the Western Cordillera of Ecuador, 10 km southwest of Quito. At least six periods of Pleistocene to Holocene activity (N1 to N6) have been preserved in the geologic record as tephra fallouts and pyroclastic flow deposits. New field data, including petrographic and whole-rock geochemical analyses of over forty soil and tephra sections, 100 pumice and lithic samples, and 10 new ¹⁴C ages allow us to constrain: (1) the tephra fall isopachs and detailed characteristics of the last two events (N5–N6) including volume estimates of the tephra and pyroclastic flow deposits and the corresponding volcanic explosivity index (VEI); (2) the petrographical and geochemical correlations between domes, tephras, and pyroclastic flow deposits; and, (3) the timing of the last 4 eruptive events and a period of quiescence that endured a few thousand years (1000–4000).     

Physically Based Modeling of the Long-Term Dynamics of Water Balance and Snow Water Storage Components in the Ob–Irtysh River Basin

Water Resources - The applicability of the previously developed technique for simulating the runoff hydrographs of northern rivers to the Ob River, which has largest basin area among Russian rivers...     

Application of Information Gain to Estimating the Seismic Tendency

Considering two seismic parameters,energy and the frequency of an earthquake as a whole from the definition of information gain in entropy,we study the information gain of M≥6.0 earthquakes from the world earthquake catalogue during 1900-1992.The results show that the information gain decreases before strong earthquakes.Our study of the recent seismic tendency of large earthquakes shows that the probability of earthquakes with M≥8.5 is low for the near future around the world.The information gain technique provides a new approach to tracing and predicting earthquakes from the data of moderate and small earthquakes.     

Prediction of the drag law for air–sea momentum exchange

In this paper, we use the inertial coupling relation as a similarity model for the air–sea boundary layer, to predict the 10-m drag coefficient. Excellent agreement with the commonly used statistical relationship of Garratt (1992) is found for a fully developed growing wind wave sea with a constant inertial drag coefficient, K_I = 1.5 × 10^–3. This suggests that the inertial coupling model can be used to realistically predict the 10 m drag coefficient under more general wind wave conditions.Acknowledgements The paper was completed while JATB was a Fellow at the Hanse-Wissenschaftskolleg in Delmenhorst, Germany, in July and August 2004. The comments of two anonymous reviewers are gratefully acknowledged.     

Study of Deep Carbonate Reservoirs in the Desert Areas by Transient Electromagnetic Method

In 1997, the TZ- 162 well in Tazhong area of the Tarim basin hit the lower Paleozoic dolomite reservoir at a depth of 5,900 m. The distribution of the dolomite reservoir, however,was very difficult to delineate due to the complex surface conditions and poor seismic properties. High-precision transient electromagnetic sounding (TEM) was conducted and good results obtained in this area. This paper discussed the principle,data processing and interpretation of this method. The resultsof studying the dolomite reservoirs demonstrated the effectiveness of the method in studying the low-resistance dolomite reservoirs in the high-resistance carbonates. This method should be an effective one to study reservoirs in areas with similar physical properties as well.     

Experience of Modeling the Seismotectonic Flow of the Earth’s Crust in Central Asia

Izvestiya, Physics of the Solid Earth - Abstract—Tectonic flow of crustal rock masses (a creep flow) in Central Asia is numerically modeled using the Stokes equations within a region limited...     

Dynamic-Stochastic Modeling of the Paleo-Caspian Sea Long-Term Level Variations (14–4 Thousand Years BC)

Water Resources - The article considers an estimate of the effect of positive feedback in the mechanism of level oscillations in the Caspian Sea on the long-term level regime. The study was based...     

Assessing the potential for future explosive activity from Teide–Pico Viejo stratovolcanoes (Tenerife,Canary Islands)

Since the onset of their eruptive activity within the Cañadas caldera, about 180 ka ago, Teide–Pico Viejo stratovolcanoes have mainly produced lava flow eruptions of basaltic to phonoltic magmas. The products from these eruptions partially fill the caldera, and the adjacent Icod and La Orotava valleys, to the north. Although less frequent, explosive eruptions have also occurred at these composite volcanoes. In order to assess the possible evolution Teide–Pico Viejo stratovolcanoes and their potential for future explosive activity, we have analysed their recent volcanic history, assuming that similar episodes have the highest probability of occurrence in the near future. Explosive activity during the last 35000 years has been associated with the eruption of both, mafic (basalts, tephro–phonolites) and felsic (phono–tephrites and phonolites) magmas and has included strombolian, violent strombolian and sub-plinian magmatic eruptions, as well as phreatomagmatic eruptions of mafic magmas. Explosive eruptions have occurred both from central and flank vents, ranging in size from 0.001 to 0.1 km³ for the mafic eruptions and from 0.01 to < 1 km³ for the phonolitic ones. Comparison of the Teide–Pico Viejo stratovolcanoes with the previous cycles of activity from the central complex reveals that all them follow a similar pattern in the petrological evolution but that there is a significant difference in the eruptive behaviour of these different periods of central volcanism on Tenerife. Pre-Teide central activity is mostly characterised by large-volume (1–> 20 km³, DRE) eruptions of phonolitic magmas while Teide–Pico Viejo is dominated by effusive eruptions. These differences can be explained in terms of the different degree of evolution of Teide–Pico Viejo compared to the preceding cycles and, consequently, in the different pre-eruptive conditions of the corresponding phonolitic magmas. A clear interaction between the basaltic and phonolitic systems is observed from the products of phonolitic eruptions, indicating that basaltic magmatism is the driving force of the phonolitic eruptive activity. The magmatic evolution of Teide–Pico Viejo stratovolcanoes will continue in the future with a probably tendency to produce a major volume of phonolitic magmas, with an increasing explosive potential. Therefore, the explosive potential of Teide–Pico Viejo cannot be neglected and should be considered in hazard assessment on Tenerife.