Variations of hydrogen in the surface-atmosphere in connection with the manifestation of seismic activity in the Eastern Caucasus

According to the literature, modern ideas about the earthquake center as one of the blocks of the hierarchical structure of the earth's crust, which loses stability during energy and mass exchange with the environment, are considered. Long-term continuous measurements (6 years) of hydrogen concentrations in the surface-atmosphere were carried out at two observation points in the Dagestan wedge tectonic region (Republic of Dagestan). It is shown that variations of hydrogen concentrations in the surface-atmosphere have annual periodicity. At the same time, in adjacent time intervals of the series, a change in the dispersion of hydrogen concentrations is noted. Initially, there is an increase in the value of the dispersion, after which it is marked by an abrupt decrease, the stages of which in most cases correspond to seismic events. A change in the dispersion value in adjacent time intervals of hydrogen concentrations implies a corresponding change in the entropy in the exciting thermodynamic system, i.e. in the earthquake focus. As a result of the relaxation of elastic energy, the thermodynamic system passes to the most probable, steady-state, and accordingly, values of dispersion of concentrations of hydrogen tend to a minimum.

DETERMINATION OF EARTHQUAKE FOCUS COORDINATES USING THE CASSINI OVAL METHOD WITH SECOND- AND FOURTH-ORDER HYPERBOLA FIGURES

Objectives. To study the dependencies obtained when determining the coordinates of an earthquake hypocentre using the figures of fourth and second orders.Method. A comparative analysis of determining the coordinates of the earthquake focus using the Cassini oval method, both taking errors in the readings of seismic sensors into account the and ignoring them, is presented.Result. A new method is proposed for determining the coordinates of the earthquake hypocentre, which uses the fourth-order figure, the Cassini oval, in the calculations. A graph is obtained for the distribution of errors in determining the coordinates of the earthquake focus (using the Cassini oval) depending on the relative position of two seismic sensors with different values of their errors in determining the difference in travel times of seismic waves.Conclusion. Since the calculation results are independent of the error sign in determining the difference in the arrival times of seismic waves, the method is suitable for the initial determination of the coordinates of the earthquake hypocentre as well as for comparison with the results of other methods for identifying the error sign.

ANALYSIS OF ERROR DISTRIBUTION DENSITY IN DETERMINING THE COORDINATES OF EARTHING EARTH IN THE METHODS OF SPHERES AND ELLIPSOIDS

Objectives The purpose of the study is to obtain an expression for determining the coordinates of the earthquake focus using the ellipsoid method, as well as testing the possibility of using the method using the figures of the second order of the ellipsoid during the initial determination of the coordinates of the earthquake hypocenter.Method A comparative analysis of the probability density of errors in the hypocentral zone of the earth's surface, in combination with various spheres, ellipsoid and hyperboloid and ellipsoids, is carried out.Result Obtained an expression for determining the coordinates of the earthquake focus by the method of ellipsoids, as well as the density of the distribution of error probabilities in the determination of the earthquake hypocenter the in calculations by the method of spheres, by the combined method of spheres, hyperboloid and ellipsoid, and also by the method of ellipsoids.Conclusion Methods used to determine the coordinates of the hypocenter ellipsoid, have large errors in comparison with the method of areas. This can explained by the fact that in determining the coordinates of the hypocenter in the sphere method, three errors are used in determining the difference in the travel times of seismic waves, while in the ellipsoid method and the combined method of the sphere of the ellipsoid and hyperboloid have four errors, which introduces final errors in the distribution. All the obtained dependences of the error distribution have the form close to the Cauchy distribution.

THE CAUSE OF HIGH INTENSITY OF SEISMICITY IN UKRAINE

In the article, the earthquake near Sumy is considered in detail. According to the authors, this earthquake occurred under the influence of several stress regimes. At the regional level: it is related to the transfer of stresses from the Vrancea zone along the mantle lineament of Sollogub; a change in the local stress field, which is created by blocks with different thicknesses of the earth's crust, with the presence of subcrustal thermal anomalies. The area of the location of the earthquake focus near the town of Sumy in tectonic terms is on the southwestern slope of the Voronezh crystalline massif near the northeastern side of the Dnieper-Donets Basin (DDB). The epicenter is confined to the northern extension of the Krivyy-Rig-Kremenchug suture zone. The earthquake focus is confined to the tectonic node formed by the eastern edge fault of the Krivyy-Rig-Kremenchug suture zone and the northern side fracture of the DDB. The main deep faults near the source of the earthquake are the northern side fault of the DDB rift and the northern extension of the Krivyy Rig-Kremenchug fault. The hypocenter of the event is in the area with sharp change in the structural plan of the Moho surface accompanied by a negative mantle gravitational anomaly. In the relief of the Moho surface, a superimposition of the structural plan of the northwestern direction, connected with the Devonian rift of the DDV, on the ancient structural plan of the Ukrainian shield and Voronezh crystalline massive is clearly visible. Within the DDV, the isohypses of the Moho surface clearly delineate the ascent to ~ 35 km in the central part of the rift. The Krivyy-Rig-Kremenchug suture zone is expressed in the Moho surface by a narrow elongated depression with depths of more than 50 km in the central part. Here, in the lower part of the cortex, the development of the crust-mantle mixture is observed. The Krivyy-Rig-Kremenchug suture zone is also distinguished by the development of high-intensity deep magnetic inhomogeneities along it. In addition, here in the lower part of the crust and in the upper mantle a linear object of high electrical conductivity is isolated. Thus, the earth's crust of the region has a pronounced physic-geological heterogeneity, which creates instability of lithostatic stress, and this, in turn, is a prerequisite for the appearance of additional stresses.

PROPERTIES OF THE GROUND MOTIONS PARAMETERS NEAR THE EARTHQUAKE FOCUS

Представлены дополнения в базу данных сильных движений: введены записи за 2015 г. с интенсивностью от 5 баллов, а также записи с эпицентральным расстоянием не больше 7 км с любой интенсивностью. Проведено исследование зависимости средних значений параметров грунтовых движений от гипоцентрального расстояния в ближней зоне землетрясения в интервалах: 0–5, 5–10, 10–15, 15–20, 20–25, 25–30, 30–40, 40–50, 0–50, 50–2000, 0–2000 км. Проведена оценка статистической значимости зависимостей. Показано, что параметры грунтовых движений имеют экстремальную точку при гипоцентральных расстояниях около 20 км, которую можно считать границей между ближней и дальней зоной землетрясения. Показано, что отношение пикового вертикального ускорения к пиковому горизонтальному ускорению (PVA/PHA) коррелирует с магнитудой события – чем выше магнитуда, тем больше значение PVA/PHA при равных прочих условиях Additions into the Strong Motions Data Base are represented: records 2015 year with the intensity from 5, and also the records with epicentral distance not greater than 7 km with any intensity. A study of the ground motions parameters average values dependence on the hypocentral distance in the neighbor zone of earthquake in the intervals: 0–5, 5–10, 10–15, 15–20, 25–30, 30–40, 40–50, 0–50, 50–2000, 0–2000 km is carried out. The estimation of the statistical significance of dependences is carried out. It is shown that the parameters of ground motions have the extreme point with the hypocentral distances about 20 km, which can be considered as the boundary between the near and far zone of earthquake. It is shown that the ratio of peak vertical acceleration to the peak horizontal acceleration (PVA/PHA) correlates with the magnitude of event – the higher the magnitude, the greater the value PVA/PHA under otherwise equal conditions.

In The Zone: Keeping hope alive through shaky times

Social service organisations exist to provide help and support when life is difficult. Maintaining this through the crisis and long recovery from significant natural disasters requires purpose, resources and care full attention to staff. Presbyterian Support Upper South Island (PSUSI) had a pre-earthquake focus on activity that supported community connectedness. The need for this type of work has become more pronounced during the two years since the September 2010 earthquakes. This article explores from a management perspective what it has taken to keep the organisation running and the challenges of flexing from core activities through the ever changing and shaky reality known as the new normal. The way the value dimensions of the organisation have been tested is canvassed as is the way they have provided an enduring capability platform. A conceptual model encompassing community needs during the quakes and for the future is developed.