Statistical estimation of the threshold of toxic effects

A method of the statistical estimation of the threshold of “no effect” and “100% effect” levels of a test compound has been suggested. The experimental data of this method concern the survival of organisms exposed to a range of concentration of toxic chemicals.     

Gravity and Displacement Variations in the Areas of Strong Earthquakes in the East of Russia

The modern gravimetry methods are capable of measuring gravity with an accuracy of up to 10^–10 of the normal value, which is commensurate with the accuracy of the up-to-date methods of displacement measurements by satellite geodesy. Significant changes, e.g., in the coseismic displacements of the Earth’s surface are recorded in the zones of large earthquakes. These changes should manifest themselves in the variations of gravity. Absolute measurements have been conducted by various modifications of absolute ballistic gravimeters GABL since the mid-1970s at the Klyuchi point (Novosibirsk) in the south of the West Siberian plate. Monitoring observations have been taking place in the seismically active regions since the 1990s. In this paper we consider the results of the long-term measurements of the variations in gravity and recent crustal displacements for different types of earthquakes (the zones of shear, extension, and compression). In the seismically active areas in the east of Russia, the longest annual series of absolute measurements starting from 1992 was recorded in the southeastern segment of Baikal region. In this area, the Kultuk earthquake with magnitude 6.5 occurred on August 27, 2008, at a distance of 25 km from the observation point of the Talaya seismic station. The measurements in Gornyi (Mountainous) Altai have been conducted since 2000. A strikeslip earthquake with magnitude 7.5 took place in the southern segment of the region on September 27, 2003. The effects of the catastrophic M = 9.0 Tohoku, Japan, earthquake of March 11, 2011 were identified in Primor’e in the far zone of the event. The empirical data are consistent with the results of modeling based on the seismological data. The coseismic variations in gravity are caused by the combined effect of the changes in the elevation of the observation point and crustal deformation.     

Determination of the Parameters of a Submerged Source by Perturbations of the Liquid Surface Based on Machine Learning Methods

Doklady Earth Sciences - The inverse problem of generating surface waves in a liquid is to determine the parameters of the source of perturbations from the waves it creates on the liquid surface. A...     

Assessment of concentration of radionuclides in river water and bottom sediments

The results of modeling of ^{89, 90}Sr, ¹³⁷Cs, and ^{239, 240}Pu migration in the Techa River are compared with observed data. It is shown that taking into account of the process of mass exchange between the main stream of a river and underflow is important for adequate modeling of migration and accumulation of radiative substances in a river. It is difficult to obtain results of modeling corresponding to the observed data if the process is neglected. Taking into account the mass exchange is especially important in developing models for long enough rivers that were polluted by radionuclides during long time. Authors believe that, in future, the considered aspects of modeling radioactive substances in rivers can be generalized on chemical polluting substances with similar physical and chemical properties, for example, heavy metals, phenols, etc.     

Fast optical variability of SS 433

We study the variability of the optical flux from the peculiar Galactic source SS 433 based on observations with the Russian-Turkish 1.5-m telescope. We describe in detail the technique of highquality photometric measurements with a time resolution of 0.3–1 s using an ordinary CCD. Through test observations of nonvariable stars, we show that atmospheric turbulence introduces no significant distortions into the light curves. Therefore, such data are well suited for studying the aperiodic variability of various objects.     

On the possibility of tsunami formation as a result of water discharge into seismic bottom fractures

A fundamentally new mechanism of tsunami generation as a result of water discharge into rapidly opening seismic fractures of the bottom is proposed. A mathematical model of the phenomenon developed within the framework of the linear potential theory is presented. The main parameters of the problem that affect the characteristics of the formed wave are revealed.     

Assessing the impact of NPP tritium discharges on water bodies

The sources of tritium production at NPPs are considered. The contemporary data on the tritium concentration in the rivers and reservoirs of Russia are presented. The Russian and foreign standards for the permissible tritium concentration in drinking water are compared. The forecast is computed of tritium concentration in a hypothetical river polluted with NPP discharges which meets the EUR tritium discharge requirements. It is demonstrated that tritium discharges from projected NPPs may reliably meet the requirements established by population exposure dose safety standards if general safety rules for tritium discharges to the environment are observed, the correct scheme of water body management is used, and the water use is reasonable.     

Parameters of Tsunami Source Versus Earthquake Magnitude

This study employs an empirical-analytical approach in combination with Monte-Carlo method to establish relationships between earthquake moment magnitude and upper limits of tsunami source parameters: double-amplitude of vertical bottom deformation, displaced water volume, and potential energy of initial elevation. The approach is based on the Okada solution for a finite rectangular fault and empirical scaling laws for earthquake sources. Results are compared to empirical and theoretical relationships published previously. Parameters of some recent tsunami sources, those for which USGS provides slip distribution data, are considered in light of the established relationships.     

Calculation of the initial elevation at the tsunami source using analytical solutions

We have obtained an analytical solution to the problem of determining the initial elevation at the tsunami source, which was formed by small residual deformations of a flat sloping bottom. This solution, which is newly derived, is compared with the known analytical solution of an equivalent problem over a horizontal bottom. It is shown that applying an analytical solution over a horizontal bottom for calculating the initial perturbations in the sources of realistic tsunami provides sufficient accuracy.     

Stratospheric ozone distribution features from the results of simultaneous ground-based microwave measurements in Nizhni Novgorod and Kyrgyzstan

Presented are the results of studying the ozone layer over Nizhni Novgorod and Central Asia using the ground-based millimeter wavelength range equipment. Carried out is the comparison of results of ground-based measurements with the EOS Aura MLS data. The difference in the ozone layer structure at stratospheric heights is revealed during the joint measurements at the mentioned points in November 2010. The analysis demonstrates that this difference is caused by the influence of the polar stratospheric vortex. Proceeding from the experience of similar researches, the conclusion is made on the necessity of organizing the permanent domestic network of the ground-based microwave monitoring of the ozone layer.