Loading protocols for European regions of low to moderate seismicity

Existing loading protocols for quasi-static cyclic testing of structures are based on recordings from regions of high seismicity. For regions of low to moderate seismicity they overestimate imposed cumulative damage demands. Since structural capacities are a function of demand, existing loading protocols applied to specimens representative of structures in low to moderate seismicity regions might underestimate structural strength and deformation capacity. To overcome this problem, this paper deals with the development of cyclic loading protocols for European regions of low to moderate seismicity. Cumulative damage demands imposed by a set of 60 ground motion records are evaluated for a wide variety of SDOF systems that reflect the fundamental properties of a large portion of the existing building stock. The ground motions are representative of the seismic hazard level corresponding to a 2 % probability of exceedance in 50 years in a European moderate seismicity region. To meet the calculated cumulative damage demands, loading protocols for different structural types and vibration periods are developed. For comparison, cumulative seismic demands are also calculated for existing protocols and a set of records that was used in a previous study on loading protocols for regions of high seismicity. The median cumulative demands for regions of low to moderate seismicity are significantly less than those of existing protocols and records of high seismicity regions. For regions of low to moderate seismicity the new protocols might therefore result in larger strength and deformation capacities and hence in more cost-effective structural configurations or less expensive retrofit measures.     

Analysis of the seismicity in the central part of the Pyrenees (France), and tectonic implications

Two temporary seismological networks have been set up in 2000 and 2002 in the central part of the Pyrenees, in a region, which appears as a transition between two domains where both the seismic activity and the tectonic regime are different. Together with the permanent networks, they allowed us to obtain precise hypocenter locations for more than 400 events with local magnitudes ranging from 1.5 to 4.6, as well as 30 new focal mechanisms. The seismicity is distributed in several clusters, which are not located along the North Pyrenean Fault, considered as the major tectonic accident resulting from the suture of the Iberian and Eurasian convergent plates when the range formed. Several small fault segments dipping to the north are identified. The maximum focal depth varies from 10 to 20 km, with variations which are roughly parallel to those of the Moho, indicating a thickening of the seismogenic layer to the east of the studied area. The obtained focal solutions reveal a predominance of normal faulting to the West and reverse faulting to the East, with strike-slip motions in between. The largest fault segment to the East, with a length of about 20 km, could possibly be related to a large historical event which occurred in 1660, with intensity IX, close to cities which have become since then important touristic centres.     

Anthropogenic dispersion of anionogenic toxicants in groundwater in the European Russia

The result of studying the anthropogenic dispersion of As, Se, Sb, Cr, V, and Mo in subsoil waters in European Russia beyond industrial and urbanized territories are presented. The sources and ways of their penetration into aquifers, the extent and dynamics of dispersion, the contrast of mass fluxes, the forms of their migration and the most typical associations of toxicants are considered.     

青藏高原北部地区地震统计区划分及地震活动特征

地震统计区的划分是研究地震活动性的重要前提和基础,通过对青藏高原北部地区构造地质背景的分析,依据地球物理特征和强震活动特点,讨论和划分该区地震活动统计区,探讨研究区地震活动的复发特点、地震构造特征、潜在地震危险性及强度,分析研究区未来强震发生的强度和可能地点,结果表明,目前青藏高原北部地区处于第8个活跃期,仍存在发生强震的可能,且未来数年存在发生7级以上地震的可能,应密切东昆仑断裂带东段和祁连山中西段地区。     

Perspectives of artificial recharge of groundwater in southern European Russia

The current state of the problem of artificial recharge of groundwater in Russia and other countries is analyzed. The factors that govern the zoning by the conditions of artificial groundwater recharge are considered. The territory of the southern European Russia was zoned by the conditions of artificial groundwater recharge and the results of this zoning were used to compile maps of perspectives of artificial groundwater recharge in southern European Russia.     

Persistent organic pollutants in subarctic lakes in the extreme North of European Russia

The paper presents data on the concentrations of persistent organic pollutants in bottom sediments of subarctic lakes on Vaygach Isl. and in the Polar Cis-Urals in the Northern European Russia. Dioxin pollution is estimated at the background level, and the recorded levels of hexachlorobenzene fall within the concentration range identified in the bottom sediments of small lakes in the southwestern Arkhangelsk region. The specific character of the congener profile of polychlorinated dibenzo-p-dioxins and dibenzofurans in bottom sediments is demonstrated, suggesting a relationship between the pollution that forms under the effect of atmospheric transport of persistent organic pollutants from low latitudes in the past and present and the application of dioxin-containing organochlorine chemicals in timber industry.     

Elevation-space and space-time analysis of water balance in European Russia

A scheme of water balance differentiation of a territory is proposed. The vertical and space-time structure of water balance are considered. A procedure for regional space-time analysis of water balance was developed and tested, allowing one to evaluate its different characteristics and relationships, to simulate the series of their mean annual values in points where no observations are available, and to carry out computeraided mapping of the obtained results. Electronic maps were constructed to characterize the distribution of river runoff and its surface and subsurface components over the European Russia, the correlation and conjunction between them, the distribution of annual precipitation, and the precipitation of the warm and cold periods over the territory. Statistical relationships, reflecting different aspects of space-time variations in the major water balance elements, are given.     

Spatial distribution of cyanotoxins and ratios of microcystin to biomass indicators in the reservoirs of the Volga,Kama and Don Rivers,the European part of Russia

We studied the distribution of cyanotoxins and potential producers, as well as the variability of microcystin to biomass parameters (chlorophyll-a; MC/Chl-a; and biovolume; MC/BV) in 12 drinking water reservoirs of the world’s largest reservoir system, the Volga-Kama-Don cascade (European part of Russia) during the summers of 2016 and 2018. MC concentrations varied from below 0.1 μg L⁻¹ in June up to 16.4 μg L⁻¹ in August and exceeded 1 μg L^-1 in 25 % of the samples. This MC variability was associated to changes in the abundance of widespread bloom formers such as Microcystis spp., Dolichospermum spp. and Planktothrix agardhii. Ratios of MC/Chl-a and MC/BV_cyano ranged up to 0.88 μg μg⁻¹ and 4.5 μg mm⁻³, respectively. Together with microcystin profiles MC/BV_cyano ratios characterized cyanobacterial populations along the reservoir cascade and they indicated a potential toxin hazard better than MC/Chl-a. The neurotoxin anatoxin-a was observed only in the most southern and hypereutrophic Tsimlyansk Reservoir (maximum 0.01 μg L⁻¹). Toxin gene analysis revealed that MC mostly originated from Microcystis and Dolichospermum. During their co-existence up to 14 MC congeners co-occurred. Cuspidothrix issatschenkoi cf. Raphidiopsis mediterranea was identified as possible neurotoxin producers.     

Zonal features of the formation of water chemistry in small lakes in European Russia

Appreciable observational data were used to reveal zonal features of the formation of the chemical composition of waters in small lakes on the territory of European Russia along a transect from tundra to the arid zone. Inter-zonal variability in the parameters of the chemical composition of waters is determined. Zonal differentiation according to hydrochemical parameters is substantiated. The main differentiating elements of the chemical composition of waters in different natural-climatic zones are distinguished. The contribution of the main natural and anthropogenic factors, determining the present-day processes of water formation is analyzed. Different degrees of the effect of non-zonal factors (including anthropogenic ones) on the formation of the chemical composition of lake waters in the humid and arid zones are demonstrated.     

Lake water resources of the European part of the Russian Federation

The article gives the results of estimating lake water resources for federal districts in European Russia and constituent entities of the Federation, carried out in the Institute of Limnology, RAS, with the use of up-to-date satellite images and the program Google Earth. European Russia contains ~610000 natural water bodies >0.1 ha in area, including ~200000 lakes >1 ha in area, and 90000 water bodies of artificial origin. Lake water resources of European Russia amount to 1370 km³ of water, of which 99% are in Northwestern Federal District. Artificial water bodies contain ~250 km³ of water resources.     

Microseismic noise in northern European Russia: Seismic recordings in the town of Vorkuta

Microseismic noise was studied in the frequency range 0.5–30 Hz in the conditions prevailing in the town of Vorkuta. A seismic noise model was developed consisting of power spectral densities of ground motion velocity separately for daytime and nighttime in different frequency ranges. The absolute noise level for frequencies of 1–5 Hz in Vorkuta varies between −140 and −150 dB in daytime and from −152 to −158 dB in nighttime, with the ranges for the 8-15 Hz noise being −140 to −155 dB in daytime and −155 to −165 dB in nighttime. Well-pronounced daily variations in noise amplitude were observed in the frequency ranges 1.5–3 Hz and 14–17 Hz. The noise amplitude varies by 7 dB over 24 hours, with the amplitude of horizontal component variation being 5 dB above that of the vertical component. The power spectral densities of ground motion velocity in the microseismic noise involve several spectral peaks, whose central frequencies did not vary by more than 0.15 Hz during the entire period of instrumental observation. The seismic background in the town of Vorkuta contains seismic events due to distant earthquakes and local industrial explosions.     

滇西南地区双震序列应力触发及地震活动性研究

利用弹性半空间模型和岩石圈介质波速模型,计算了1976年龙陵7.3、7.4级地震和1988年澜沧-耿马7.6、7.2级地震2次双震间及对后续地震的应力变化影响,同时对该区未来地震活动性进行了研究。得到以下结论:1龙陵双震属共轭型双震活动,前一次地震的发生对后一次地震有抑制作用;而澜沧-耿马地震则属于牵动型双震活动,澜沧7.6级地震对其后的耿马7.2级地震有一定的触发作用,其库仑应力变化值为0.35bar;2绝大多数后续余震受到了主震的应力触发作用,其中龙陵双震触发效果较明显;3根据震后粘弹性松弛应力场变化得出,现阶段NW向的腾冲-龙陵、永德-勐省以及澜沧东南地区,NE向的瑞丽、镇安、大理、上允、永平等地区地震危险性有所增强,这与该区地震活动性增强相吻合。     

Impact of changes in the conditions of European Russia forests on annual river runoff

Based on the methods of O.I. Krestovskii and recent information on the forestry of European Russia, the article offers the assessment of the impact of transformations in the structure of forests in the recent decades on the river runoff and evaporation. The accompanying changes in the runoff are shown to be relatively insignificant; however, in the XXI century they may become more significant and manifest themselves not only at the local but also at the regional level.     

Concentration and localization of hydroxylamine in the reservoirs and lakes in the territory of European Russia

Hydroxylamine concentration and localization in the Volga reservoir cascade and in the lakes of Yaroslavl province and Vladimir province were studied. It was found that, in microaerophilic zones of the most productive lakes, the rate of hydroxylamine formation is higher and its localization does not depend on the type of the limnological object (a reservoir or a lake), but is determined by the oxygen regime of the water body in question.     

Magnetic declination measurements over European Russia and Siberia in the 18th century

The paper presents the history of measurements of the geomagnetic field parameters over the territory of Russia in the 18th century derived from archival and literature sources. Topographical mapping of the European territory and neighboring seas of the Russian Empire from the late 17th to the mid 18th century during which magnetic measurements were made was of great importance for determining magnetic declination. The magnetic declination in Siberia and its neighboring seas was measured for the first time during the first expedition of V. Bering in 1728 and then during his second expedition (the Great Northern Expedition) in 1733–1742. Magnetic measurements were carried out along the northern coast of Siberia and in the Bering Sea. The academic group of the expedition performed magnetic declination measurements over southern regions of Siberia (Krasnoyarsk, Irkutsk, Nerchinsk, Yakutsk, etc.) in 1735 and 1736. During the second half of the 18th century, Russian expeditions determined geographical coordinates of the cities of European Russia and carried out magnetic declination measurements for them. During these expeditions Inokhodtsev paid attention to the anomalous magnetic declination in the Kursk region. In his opinion, the anomaly could have been caused by the presence of iron ore.     

Submarine discharge into the seas of the Arctic Ocean from the European Russia territory

Groundwater formation conditions in the upper hydrodynamic zone of the northern coast of European Russia are considered. This groundwater discharges directly into the Barents and White seas. The values of submarine discharge from European Russia into arctic seas, bypassing river network, are estimated. Estimates of subsurface dissolved-solids discharge are given. Specific and integral characteristics of submarine discharge are analyzed. The major regularities in the formation and distribution of submarine discharge into seas of the Arctic Ocean are described.     

Hydrochemical features of boggy river sources and lakes in central European Russia

Water chemistry in deep freshwater lakes and springs, situated in boggy areas and giving rise to the majority of the Russian rivers, is considered. Those lakes and springs can serve as an important reserve of fresh drinking water.     

Evaluating Water Quality in a Large River System in the Northern European Russia by Macrozoobenthos

Water Resources - Macrozoobenthos analyses were used to evaluate the ecological water quality in the Shuya River, a large tributary of Onega Lake, which determines water chemistry in the water...     

The formation of present-day resources of surface and subsurface waters in European Russia

Variations in the characteristics of the annual, dry-season, and minimal monthly runoff in rivers of European Russia for the recent 35 years (1975?C2005) have been estimated and analyzed in comparison with a period of approximately the same duration (1935?C1969). The genesis of runoff for different river basins and the major causes of current changes in runoff characteristics have been studied. Regional regularities in the hydrological and geohydrological processes have been identified, and zoning of the territory has been performed with identification of specific features in the formation of river runoff in the European North and the basins of the Volga, Don, Ural, etc. The natural resources of surface and subsurface waters over 1970?C2005 have been re-estimated with the construction of appropriate maps. Water availability and load on water resources have been analyzed.     

Re-appraisal of seismicity and seismotectonics in the north-eastern Algeria Part I: Review of historical seismicity

As large destructive seismic events are not frequent in Algeria, anexhaustive knowledge of the historical seismicity is required to have arealistic view of seismic hazard in this part of the world. This research workpresents a critical reappraisal of seismicity in the north-eastern Algeria forseismotectonic and seismic hazard purposes. This part of work focuses onthe seismicity of pre-1900 period for the area under consideration[33^°N-38^°N, 4^°E-9.5^°E]. By going back tothe available documentary sources and evaluating and analysing the eventsin geographical, cultural and historical context, it has been possible toidentify 111 events, from 1850–1899, which are not reported in therecent Algerian catalogue. Several spurious events, reported in standardlistings, have been deleted and nine unknown events have been discovered.It is quite clear that macroseismic information derived from press reportsand published documents in Algeria, under certain conditions, is veryincomplete, even for destructive earthquakes, located in the countrysideaway from communication centres. One of the reasons for this iscensorship, noticeable during the colonisation period. Critical analysis ofnewly collected information has allowed the determination and/or theimprovement of the macroseismic parameters of each event, such aslocation, maximum epicentral intensity and magnitude to produce anearthquake catalogue as homogeneous and complete as the available data,for the zone under study. The criteria used in this research are explainedand eight historical earthquakes have been the subject of retrospectivemacroseismic field construction.The investigation of historical earthquakes is one of the most important taskin studying seismotectonic for seismic hazard evaluation purposes.