The spectral and dynamic parameters of the sources of regional seismic events have been studied for the territory of the Northwestern Caucasus using stations from the network of the Geophysical Survey, Russian Academy of Sciences and Crimean network. This is the first study for the region using such a large dataset. Moment magnitudes-Local magnitude calibration have been established for earthquakes of small and medium magnitude in the study area and linear dependence Mw = ML + 0.16 is recommended for use. An interdependence between the values of energy classes and local magnitudes was also obtained, which can help to further improve the procedures for processing seismological monitoring data at Caucasian stations and the formation of regional catalogs.
The results of theoretical and experimental studies on thermal processes in the Elbrus volcanic center and adjacent territories are presented. Distributed temperature measurements on the Elbrus volcano and in the NorthernCaucasus Geophysical Observatory have been performed. Series of measurements were also performed with an aid from autonomous systems for temperature («High Capacity Temperature Loggers iButton» and «Rejim-avtomat-termo-10-100») monitoring in the mountain lake located near the Maloye Azau glacier. The comparative analysis of the results for different years is provided. On the basis of the Geophysical Observatory in Northern Caucasus, in the laboratory located some 20 km from the Elbrus volcano in the tunnel at a depth of 4 km the array of temperature sensors has been deployed. Results of continuous observations over variations of underground temperatures, including pin-point measurements in the vicinity of sources of carbonaceous mineral waters are presented and discussed. Based on the results of temperature measurements in the 180-meter deep borehole drilled in the ice cap on the western plateau of the Elbrus volcano the theoretical estimations of possible deep temperatures and heat flux values have been obtained and corresponded to the proposed location of the peripheral magma chamber. Thus, the original scientific results provide significant extension to our knowledge on possible resumption of volcanic activity in the vicinity of Mount Elbrus.
Abstract For the first time, we monitored the Elbrus volcano activity detecting volcanic gases emanating through pores using an unique eye-safe LIDAR system. A highly sensitive eye-safe LIDAR system was developed for monitoring the fracture-emitted aerosol, which is transported by volcanic gases inside a hot tunnel near the Elbrus Mountain. The developed LIDAR is based on a diode laser (transmitter, 910 nm, 3 ns, <1 µ J cm −2 ) and a single-photon avalanche photodiode (detector). From August to October 2019, within the first months of the LIDAR monitoring, we have detected a two-fold decrease in the fracture-emitted aerosol emanation, while other parameters in the tunnel remained relatively stable (radon concentration, air temperature and humidity changed less than by 1%). A significant correlation between the LIDAR signal of volcanic aerosol and the Earth’s crust deformation measured by the laser strainmeter located nearby was found. Based on our preliminary experiments we consider the new LIDAR system as a sensitive, economical and robust instrument for Earth’s crust deformation and volcanic activity monitoring and eruption precursor observation.
A new-generation eye-safe lidar has been developed for tectonic aerosol sensing. The lidar was installed inside an adit of Baksan Neutrino Observatory to quantify tectonic aerosol fluctuations. As aerosol fluctuations are induced by Earth's crust deformations, a laser strainmeter was used to measure the deformations. A correlation of strainmeter and aerosol lidar signals was observed during low-frequency Earth's crust deformations.
Актуальность работы. Изучение изменений локального геомагнитного поля с целью выявления предвестников сильных землетрясений, особенно в сейсмоактивных регионах, где расположены большие города и объекты особо важного значения (АЭС, водохранилище и т.п.) остается одной из главных задач современной науки. В разных странах мира, используя магнитометрические методы, проводятся исследования по поиску предвестников сильных землетрясений. Цель. Однако, за первую половину XX века, несмотря на отдельные попытки ученых Японии и других стран, серьезных результатов достичь не удалось. Установлено, что с развитием геодинамических процессов в земной коре, особенно при подготовке сильных землетрясений, происходят изменения в магнитных свойствах горных пород (электропроводности, диэлектрической и магнитной проницаемости). Геомагнитные вариации, создаваемые внешним источником, несут в себе важную информацию об изменениях в физических свойствах в земной коры и верхней мантии, а так же позволяют оценить эти изменения. Методы. Представлена методика, которая позволяет с помощью изучения вариаций локального геомагнитного поля, создаваемых внешним источником, выявить изменения в электропроводности на разных глубинах земной коры и верхней мантии, связанные с развитием геодинамических процессов. С этой целью использован расчетный параметр N(A), который является отношением амплитуд вариаций геомагнитного поля внешнего происхождения, измеренных синхронно на разных парах станций. Изучены вариации с периодами 1025, 3060 минут и Sq-вариации. Метод применяется в низкоширотных областях Земли, где вариации переменного геомагнитного поля хорошо выделяются. Результаты. Используя предлагаемую методику, на территории Армении были выявлены аномальные изменения локального отклика геомагнитного поля перед Парванийским 1986 г. (М5,4) и Спитакским 1988 г. (М7,0) землетрясениями. Предполагается, что причинами изменений в физических свойств геологической среды в частности электропроводности, являются дегазация Земли и вертикальная фильтрация флюидов в верхние слои земной коры Relevance. The study of local geomagnetic field changes in order to identify harbingers of strong earthquakes, especially in seismically active regions where large cities and especially important objects (nuclear power plants, a storage reservoir, etc.) are located remains one of the main tasks of modern science. In different countries studies are being conducted to search for precursors of strong earthquakes, using magnetometric methods. Aim. However, for the first half of the 20th century, despite some attempts by scientists from Japan and other countries, no serious results were obtained. It has been established that with the progress of geodynamic processes in the earths crust, especially during the preparation of strong earthquakes, changes in the magnetic properties of rocks (electrical conductivity, dielectric and magnetic permeability) occur. However, geomagnetic variations created by an external source carry important information about changes in physical properties, in particular, electrical conductivity in the earths crust to the upper mantle, and make it possible to evaluate these changes. Methods. A technique that allows to identify changes in electrical conductivity at different depths of the earths crust and upper mantle associated with the development of the geodynamic process, using the study of local geomagnetic field variations created by an external source, is presented. For this purpose, parameter N(A), which is the ratio of the amplitudes of variations of the geomagnetic field of external origin, measured synchronously at different pairs of stations, was used. Variations with periods of 10-25, 30-60 minutes and Sq-variations were studied. The method is used in low latitude areas of the Earth, where variations of the variable geomagnetic field stand out well. Results. Anomalous changes in the local geomagnetic field were revealed in Armenia before the Parvania 1986 (M 5.4) and Spitak 1988 (M 7.0) earthquakes, using the proposed methodology. It is assumed that the causes of changes in the physical properties of the geological environment, in particular, electrical conductivity, are most likely to be the degassing of the Earth and the vertical filtration of fluids into the upper layers of the earths crust
