Impact of anthropogenic and natural factors on the air quality above the northern Caspian Sea and the ecological risk level for the human population in the coastal zone

The paper reports monitoring results (obtained in 2000–2001) of the seasonal variations in the quality of lower atmospheric air in the coastal zone of the northern Caspian Sea due to the occurrence of aerosols with submicrometer-sized particles and soot in the lower atmosphere. The contributions of natural and anthropogenic factors to the ecological risk for the local human population are evaluated, along with the contribution of the premature mortality of the human population in the coastal zone in 2005 to its overall average death rate for the Russian Federation (approximately 24%). The authors’ estimates are consistent with those made by the World Health Organization at the United Nations (WHO) for the Russian Federation as a whole (approximately 21%). The information presented in this publication is important for evidence-based recommendations on preventive environment-protective measures to be taken with regard for the development of oil and gas fields on- and offshore the northern Caspian Sea.     

Near Islands Aleutian Earthquake with MW = 7.8 on July 17, 2017: I. Extended Rupture along the Commander Block of the Aleutian Island Arc from Observations in Kamchatka

Izvestiya, Physics of the Solid Earth - The largest instrumentally recorded regional back-arc earthquake with MW = 7.8, MC = 8.2 occurred on July 17, 2017 on the Bering transform fault (the...     

Dynamics of radiation belt relativistic electrons in November 2004–January 2005

The radiation belt dynamics during the extreme solar events in November 2004 and January 2005 is studied based on the measurements of relativistic electrons (with energies of 0.8–8 MeV) on the Express-A2 geostationary satellite and Meteor-3M polar satellite. New radiation belts of relativistic electrons in the space (L ～ 3) between the stationary outer and inner belts were formed as a result of either superstorm (|Dst|_max = 373 and 289 nT). The position of the maximums of these belts (L _max = 2.9 and 3.1) coincides with the known dependence of L _max on the magnetic storm Dst variation amplitude: |Dst|_max = 2.75 × 10⁴/L _max ⁴ . In November–December the new belt very slowly (ΔL ～ 0.1 per month) shifted toward the Earth. During the series of moderate (～100 nT) magnetic storms that developed as a result of the extreme solar events in January 2005, the belt in the space shifted toward deeper L shells (L ～ 2.5). The moderate January storms produced new belts with L _max ≥ 4.     

Annihilation radiation from a power-law distributed electron-positron plasma on the ground Landau level: the case of low magnetic fields

Intensity, polarization, and cooling rate of the two-photon annihilation radiation are studied in detail in the case of one-dimensional power-law distributions of electrons and positrons, assuming that they occupy the ground Landau level in a strong magnetic fieldB10¹⁰–10¹² G. Simple analytical expressions for limiting cases are obtained and results of numerical calculations of radiation characteristics are presented. Power-lawe ^± distributions _{± ±} ^–k are shown to generate power-law spectra of the annihilation radiation atEmc ² andEmc ², with indices depending on the direction of radiation. The annihilation spectra at =0 show the largest blue-shifts of their maxima and the hardest high-energy tailsI(Emc ², =0)E ^–(k–1). The blue-shifts reduce, and the hard tials steepen, with increasing . At >(2mc ²/E)^1/2 the slopes of the high-energy tails rapidly transform to that at =2,I(Emc ², =/2)E ^–(2k+3). The direction-integrated spectraS(E) also display the power-law tials at low and high energies,S(Emc ²)E ^–(k+1). The total annihilation rate and energy losses decrease with decreasingk, being higher than for the isotropice ^± power-law distributions at the samek. The radiation is linearly polarized in the plane formed by the magnetic field and wave-vector. The polarization degreeP is maximum atEmc ²:P _max0.6 for =/2. Annihilation features and power-law-like hard tails observed in many gamma-ray burst spectra may be associated with the annihilation radiation of the magnetized power-law distributed plasma near neutron stars. Comparison of the observed and theoretical spectra allows one to estimate the power-law index of thee ^– e ⁺-distribution and the gravitational redshift factor in the radiating region.     

New paleomagnetic data on the Anabar Uplift and the Uchur-Maya region and their implications for the paleogeography and geological correlation of the Riphean of the Siberian Platform

The results of paleomagnetic studies of the reference sections of the Riphean and Late Proterozoic intrusive bodies of two remote areas of the Siberian Platform are presented. Within the limits of the Uchur-Maya region the sedimentary rocks of the Gonam, Omakhta, Ennin and Konder formations were studied; and the Riphean sedimentary rocks of the Burdur and Kotuykan formations on the northern and western slopes of the Anabar Uplift and, also, the Late Proterozoic intrusive complexes, located in the basins of the Fomich, Magan, Dzhogdzho and Kotuykan Rivers were studied. The paleomagnetic poles obtained in the course of this work and the present-day geochronological data give grounds to assume that: (1) the accumulation of the Riphean of the Anabar Uplift occurred after the formation of the Uchurskaya series of the Uchur-Maya region and was completed in approximately 1.5 Ga; (2) the Konder layers, compared according to the correlation pattern accepted at the present time [Semikhatov and Serebryakov, 1983] with the bottoms of the Totta formation, can be related to the appreciably more ancient stratigraphic level; (3) the intrusion of the studied intrusive bodies of the northern and western slopes of the Anabar Uplift occurred nonsimultaneously, although within close time intervals of approximately 1.5 Ga. The estimates of the kinematic parameters of the drift of the Siberian Platform within an interval of 1.7–1.0 Ga is carried out.     

Toxicity assessment of bottom sediments in watercourses in Selenga River basin on the territory of Mongolia

Bioassay methods are used to assess the toxicity of bottom sediments in the main watercourses of the Selenga River basin and Lake Orog in Mongolia. Toxic bottom sediments are found in a brook in the region of the Erdenet Mining and Concentration Complex, as well as in the Eroo and Bukhlyn rivers, which experience the effect of intense gold mining. The conclusion is drawn that the Selenga River water flowing from the territory of Mongolia cannot directly affect the quality of water in Lake Baikal.     

Subduction of the Pacific plate under Kamchatka: Seismic velocity of underthrust

The results of studying the process of underthrusting in the Pacific plate under Kamchatka are presented, and the phenomena associated with this process are described. The seismic component of the velocity of the plate underthrust is estimated on the basis of (1) data from the CMT (Centroid Moment Tensor) catalog and (2) the sequence of the strongest Kamchatka earthquakes. A flat site with a strike azimuth of 217° and a dip angle of 25° located at depths of 30–70 km is assumed to be the interface between the plunging plate and Kamchatka. From CMT focal mechanisms, the underthrust velocity is estimated at V = 0.7 cm/yr for the southern zone (located south of Cape Shipunski) and at V = 1.1 cm/yr for the central zone (from Cape Shipunski to Cape Kronotski). From pairs of the strongest earthquakes that have occurred successively since 1737, the underthrust velocity for the southern zone is estimated at V = 6.6–7.1 cm/yr (from two pairs) and for the central zone, at V = 6.6 cm/yr. The creep portion of the underthrust amounts to 5–15% of the total velocity (the velocity of motion of the Pacific plate is 8 cm/yr).     

Structural features of the planetary boundary layer in the continent-ocean transition zone as inferred from data of lidar and meteorological soundings

The results of an analysis of the annual variation of the planetary boundary layer (PBL) height in the continent-ocean transition zone determined from lidar and meteorological data are presented. Means of the height and its variances are calculated in a month-long window. The PBL heights reconstructed from these measurements are found to differ substantially in the spring and summer seasons. These results are explained by the influence of dust storms and cyclones, which are the most intense in these seasons, on the structure of aerosol in the atmosphere.