This paper presents results from a study of the deep structure of the Elbrus edifice and adjacent areas using geophysical techniques. We confirmed the existence of a shallow magma chamber, derived a...

Field experiments involving molecular-electronic seismometers, along with conventional pendulum geophones, were performed to study the deep structure of the upper crust (in the area of the Kaluga ring structure) by passive seismic methods. The microseismic sounding survey was carried out along a geophysical profile crossing the central part of the structure with simultaneous data acquisition by molecular-electronic and conventional seismometers at each measurement point. Experimental data on the propagation of Rayleigh waves along the curvilinear surface have been collected. The feasibility of using molecular-electronic seismometers for passive seismic studies has been confirmed by the results of comparative analysis of the vertical geophysical cross sections, which reveal upper crustal heterogeneities, and by the results of a series of laboratory tests.

Geophysical processes preceding the seismic event in the region of Ryukyu Islands are analyzed on the basis of observatory data. Conditions for generation and structural features of the induced gravimagnetic disturbances are specified.

The new-generation geohydroacoustic buoy prototype is designed for simultaneous acquisition of acoustic, hydroacoustic, and seismoacoustic data in various environmental conditions, including onshore and offshore boreholes, yet is specifically targeted for operation in Arctic seas as an element of the distributed ice-class drifting antennas. Modular structure of the geohydroacoustic ice buoy incorporates the advanced data logger and a combination of sensors: vector–scalar hydroacoustic (0.01–2.5 kHz) accelerometer, broadband molecular–electronic (0.03–50 Hz) velocimeter, as well as optional hydrophones. The distinguishing feature of the geohydroacoustic buoy is its low power consumption responsible for consistent autonomous operation of the entire measurement system for at least one week. Results of continuous laboratory tests carried out at the geophysical observatory of the Geophysical Survey of the Russian Academy of Sciences (GS RAS) in Obninsk are presented. It has been confirmed via comparative analysis of recorded time series featuring microseismic noise and teleseismic earthquakes that the prototype well meets the high standards of modern seismology.

The spectral and dynamic parameters of the sources of regional seismic events for the territory of the Northwest Caucasus has been studied based on the data from the stations of the Geophysical Survey, Russian Academy of Sciences, and from the Crimean seismic network. This is the first study for this region using such a large dataset and comparing the values of the moment and local magnitudes. The relationships for the moment and local magnitudes are established for earthquakes of small and medium magnitudes in the study area and the linear dependence M_w = M_L + 0.16 is recommended for use. A relationship connecting values of energy classes and local magnitudes is also obtained, to help in further improvement of the procedures for processing of seismological monitoring data from the stations of the Caucasus region and the preparation of unified regional catalogs.