Strong variations of cosmic ray intensity during thunderstorms and associated pulsations of the geomagnetic field

Strong variations of the intensity of secondary cosmic rays during thunderstorms are found to be accompanied in some cases by very clear pulsations of the geomagnetic field. The experiment is carried out in the Baksan Valley, North Caucasus, the Carpet air shower array being used as a particle detector. Magnetic field measurements are made with high-precision magnetometers located deep underground in the tunnel of the Baksan Neutrino Observatory, several kilometers apart from the air shower array.Comment: 8 pages, 2 figure

СЕЙСМОГРАВИТАЦИОННЫЕ ПРОЦЕССЫ, СОПРОВОЖДАЮЩИЕ ЭВОЛЮЦИЮ СЕЙСМОФОКАЛЬНЫХ СТРУКТУР ЛИТОСФЕРЫ

Observations reflecting the structure and conditions of the seismogravitational process in the lithosphere were analyzed using the data on the catastrophic tsunamigenic earthquake of Maule (Chile) [Sobisevich et al., 2019]. Seismogravitational processes were first identified by a group of Soviet scientists from the city of Leningrad (now St. Petersburg) under the leadership of Professor E.M. Linkov [Linkov et al., 1982, 1990]. The study of these processes continues at the North Caucasus Geophysical Observatory of IPE RAS, which was established in 2004. Experiments are carried out using unique quartz tiltmeters designed by D.G. Gridnev, which ensure the stable registration of long–period seismogravitational processes on the scale of the Earth [Sobisevich, 2013; Sobisevich et al., 2017].На примере катастрофического цунамигенного землетрясения Мауле (Чили) анализируются результаты обсерваторских наблюдений, отражающие структуру и условия формирования сейсмогравитационного процесса в литосфере [Sobisevich et al., 2019]. Показано, что сейсмогравитационные процессы были впервые выделены группой советских ученых из г. Ленинграда (ныне г. Санкт-Петербург) под руководством профессора Е.М. Линькова [Linkov et al., 1982, 1990]. Изучение этих процессов продолжается на базе Северокавказской геофизической обсерватории ИФЗ РАН, которая была развернута в 2004 г. В экспериментах задействованы уникальные кварцевые наклономеры системы Д.Г. Гриднева, которые обеспечивают устойчивую регистрацию длиннопериодных сейсмогравитационных процессов в масштабах Земли [Sobisevich, 2013; Sobisevich et al., 2017]

VIBROSEISMIC INVESTIGATIONS OF THE BAIKAL RIFT ZONE WITH A POWERFUL CVO-100 VIBRATOR

The article provides an overview of vibroseismic studies carried out in the Baikal rift zone using LargeScale Research Facilities – a powerful CVO-100 seismic vibrator, installed at the South Baikal geodynamic test site SB RAS. Research is carried out according to several methods focused on different tasks: study of the structure of the Earth’s crust and upper mantle in the BRZ, active vibroseismic monitoring, and verification of velocity models of the Earth’s crust. To study the structure of the Earth’s crust and the upper mantle, there were done the vibrator-generated wavefield recordings at the stationary regional network of seismic stations in the Buryat and Baikal branches of the Federal Research Center of the GS RAS, as well as the experimental studies involving the mobile networks deployment (ICMMG SB RAS, SIPE RAS, GIN SB RAS). The aim of the work is to carry out deep vibroseismic sounding of the Earth’s crust (vibro-DSS) at the junction of the Siberian platform, the BRZ and the Sayan-Baikal folded area. The methodology is based on the study of vibration seismograms with the determination of arrival times of the main groups of waves and their correlation with the velocity models of the Earth’s crust in the BRZ. A CVO-100 vibrator and a regional network of seismic stations are used to carry out active vibroseismic monitoring of the southern part of the BRZ. The active monitoring area is about 500×200 km. During vibroseismic monitoring, there were done thorough studies of seasonal variations of the vibrator-generated wavefield and the development of techniques for spectral correction of seismograms. A seismic vibrator CVO-100 was used to carry out experimental verification of the velocity models of the Earth’s crust, developed based on the BEST and PASSCAL experimental data. The vibrational deep seismic sounding (vibro-DSS) on the Baikal – Ulan Bator profile was carried out by the ICMMG SB RAS, GIN SB RAS and BB FRC GS RAS (Russia) in cooperation with IAG MAN (Mongolia)

ВИБРОСЕЙСМИЧЕСКИЕ ИССЛЕДОВАНИЯ БАЙКАЛЬСКОЙ РИФТОВОЙ ЗОНЫ С МОЩНЫМ ВИБРАТОРОМ ЦВО-100

The article provides an overview of vibroseismic studies carried out in the Baikal rift zone using LargeScale Research Facilities – a powerful CVO-100 seismic vibrator, installed at the South Baikal geodynamic test site SB RAS. Research is carried out according to several methods focused on different tasks: study of the structure of the Earth’s crust and upper mantle in the BRZ, active vibroseismic monitoring, and verification of velocity models of the Earth’s crust. To study the structure of the Earth’s crust and the upper mantle, there were done the vibrator-generated wavefield recordings at the stationary regional network of seismic stations in the Buryat and Baikal branches of the Federal Research Center of the GS RAS, as well as the experimental studies involving the mobile networks deployment (ICMMG SB RAS, SIPE RAS, GIN SB RAS). The aim of the work is to carry out deep vibroseismic sounding of the Earth’s crust (vibro-DSS) at the junction of the Siberian platform, the BRZ and the Sayan-Baikal folded area. The methodology is based on the study of vibration seismograms with the determination of arrival times of the main groups of waves and their correlation with the velocity models of the Earth’s crust in the BRZ. A CVO-100 vibrator and a regional network of seismic stations are used to carry out active vibroseismic monitoring of the southern part of the BRZ. The active monitoring area is about 500×200 km. During vibroseismic monitoring, there were done thorough studies of seasonal variations of the vibrator-generated wavefield and the development of techniques for spectral correction of seismograms. A seismic vibrator CVO-100 was used to carry out experimental verification of the velocity models of the Earth’s crust, developed based on the BEST and PASSCAL experimental data. The vibrational deep seismic sounding (vibro-DSS) on the Baikal – Ulan Bator profile was carried out by the ICMMG SB RAS, GIN SB RAS and BB FRC GS RAS (Russia) in cooperation with IAG MAN (Mongolia). В статье приведен обзор вибросейсмических исследований, выполняемых в Байкальской рифтовой зоне с использованием уникальной научной установки – мощного сейсмического вибратора ЦВО-100, установленного на Южно-Байкальском геодинамическом полигоне СО РАН. Работы проводятся по нескольким методикам, ориентированным на решение различных задач: исследование структуры земной коры и верхней мантии в Байкальской рифтовой зоне (БРЗ), активный вибросейсмический мониторинг, верификацию скоростных моделей земной коры. Для изучения структуры земной коры и верхней мантии проводится регистрация волнового поля вибратора на стационарной региональной сети сейсмостанций Бурятского и Байкальского филиалов ФИЦ ЕГС РАН, а также экспериментальные исследования с развертыванием мобильных сейсмических групп (ИВМиМГ СО РАН, ИФЗ РАН, ГИН СО РАН). Целью работ является проведение глубинного вибросейсмического зондирования земной коры (вибро-ГСЗ) в зоне сочленения Сибирской платформы, БРЗ и Саяно-Байкальской складчатой области. Основу методики составляет изучение вибрационных сейсмограмм с определением времен прихода основных групп волн и их увязка со скоростными моделями земной коры в БРЗ. С использованием вибратора ЦВО-100 и региональной сети сейсмических станций проводится активный вибросейсмический мониторинг южной части БРЗ. Область активного мониторинга составляет примерно 500×200 км. При проведении вибросейсмического мониторинга были детально исследованы сезонные вариации волнового поля вибратора и разработаны методики спектральной коррекции сейсмограмм. С использованием сейсмического вибратора ЦВО-100 была выполнена экспериментальная часть работ по верификации скоростных моделей земной коры, построенных по данным экспериментов BEST и PASSCAL. Работы по вибро-ГСЗ на профиле Байкал – Улан-Батор проводились ИВМиМГ СО РАН, ГИН СО РАН, Бурятским филиалом ФИЦ ЕГС РАН (Россия) совместно с ИАГ МАН (Монголия).

Anomalous geomagnetic disturbances induced by catastrophic tsunamigenic earthquakes in the region of Indonesia

Analysis of geomagnetic variations registered by the stations of the North-Caucasian geophysical observatory (the Elbrus volcanic area) has been fulfilled. Anomalous "quasi-harmonic" magnetic disturbances have been distinguished which were observed during all the stages of development of catastrophic tsunami-producing earthquakes in the area of Indonesia and morphologic effects in variation structure of geomagnetic field of the Earth have been described. Experimental results cited permit to obtain general idea on geomagnetic activity and some features of induced geomagnetic disturbances which we refer to tsunami-producing earthquakes. In all the observed cases seismic events occurred under the conditions of specific ratios between the components of magnetic field; it has been found that in the structure of magnetic variations we succeeded to distinguish ultra-low-frequency quasi-harmonic wave forms of geomagnetic disturbances reflecting the conditions of preparation and development of tsunami-producing earthquake in the studied region. We do not consider in the paper the forecast of tsunamiproducing earthquakes because even if we can distinguish in geomagnetic field some specific indications, in the source preceding the start of seismic event its coordinates and time in the source are left uncertain so far

SEISMOGRAVITATIONAL PROCESSES ACCOMPANYING THE EVOLUTION OF SEISMIC FOCAL STRUCTURES IN THE LITHOSPHERE

Observations reflecting the structure and conditions of the seismogravitational process in the lithosphere were analyzed using the data on the catastrophic tsunamigenic earthquake of Maule (Chile) [Sobisevich et al., 2019]. Seismogravitational processes were first identified by a group of Soviet scientists from the city of Leningrad (now St. Petersburg) under the leadership of Professor E.M. Linkov [Linkov et al., 1982, 1990]. The study of these processes continues at the North Caucasus Geophysical Observatory of IPE RAS, which was established in 2004. Experiments are carried out using unique quartz tiltmeters designed by D.G. Gridnev, which ensure the stable registration of long–period seismogravitational processes on the scale of the Earth [Sobisevich, 2013; Sobisevich et al., 2017]

The nature of bifocal source of the earthquake and precursors of the blow

On the base of ousting principle and application of the data on location bifocal model of earthquake source is proposed, which includes zones of dilatancy and compaction. The first one corresponds to the recognized set of precursors and the second one compensates the changes of the fissures volume. The sources of radon delineate dilatancy zone (the beginning of fissures growth). Hypocenter of the main blow is in the transitional zone. Existence of two foci in the source of earthquake is confirmed experimentally on the base of gravity data and observations of the ocean surface level. Anomalous magnetic disturbances in variations of magnetic field of the Earth are being analyzed, which can be considered as a short-term precursor. This type of disturbances is inseparably connected with tectonomagnetic effects in lithosphere and other geo-spheres. The data of experimental observations of magnetic disturbances-precursors have been presented, which allow to draw a conclusion that they are induced by internal sources located in the lower geo-spheres of the Earth

Multi-component electrode systems in geo-electric field intensity sensors for moving carriers

As an object of research, the electromagnetic field represents a set of parameters characterizing its electric and magnetic components. Methods and gages to measure the magnetic component of the Earth electromagnetic field are developed more explicitly than those for the electric one while an increasing need to measure the latter becomes of current importance when investigating the geodynamic activity in seismically dangerous regions by geo-electric methods. The experimental study of electric component of electromagnetic field in conducting media concerns the vector fields possessing E electric intensity. Generally, this is a three-dimensional field. The paper considers two- and three- component electrode systems in contact sensors of electric field intensity. The design of electrode systems most optimally meets requirements for devices to be set on mobile platforms for specific needs. It offers some designing aspects of evenly moved in conducting media sensors of alternating electric field for the frequencies in the range from units of Hz to tens of kHz. The feature of electrode systems is that the number of electrodes outnumbers the registered components of the electric field vector by one. Thus, nearly identical flow conditions in the vicinity of electrodes, geometric symmetry of the electrode system, and electric symmetry of measuring channels and, consequently, with no mutual influence of measuring channels at each other are provided. Using the task solutions of field theory the equivalent circuit parameters of primary converter of electrode sensor versus its geometrical sizes are defined. Optimum ratios of the geometrical sizes of primary converter are obtained. The offered criterion of optimization provides a maximum coefficient of transformation and sensitivity of measuring system. The paper considers an option of hardware implementation to measure the components of electric field intensity vector. The given results allow us to design symmetric multicomponent electrode systems for research of alternating electric fields, develop a circuit of their hardware implementation as applied to specific conditions of experiment. Practical research of such studies will allow to have more complete and reliable information about time-space anomalies of geoelectric field that, in turn, is necessary for research of the phenomena and the processes, from which such anomalies arise