Taking into Account the Influence of Relief in the Method of Microseismic Sounding

The traveling of surface waves in a model geophysical medium with a nonsmooth boundary is studied. It is shown that relief significantly distorts the microseismic noise field recorded at the day surface. This result should be taken into consideration when interpreting the data of passive surface-wave geophysical studies of deep crustal inhomogeneities.     

Erratum to: The Regional Tidal Response of the Geophysical Medium

Doklady Earth Sciences - An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X22050208     

Moments of inertia and the Chandlerian period for two-and three-layer models of the Galilean satellite Io

We consider two-layer (Fe-FeS core+silicate mantle) and three-layer (Fe-FeS core+silicate mantle+crust) models of the Galilean satellite Io. Two parameters are known from observations for the equilibrium figure of the satellite, the mean density ρ₀ and the Love number k₂. Previously, the Radau-Darwin formula was used to determine the mean moment of inertia. Using formulas of the Figure Theory, we calculated the principal moments of inertia A, B, and C and the mean moment of inertia I for the two-and three-layer models of Io using ρ₀ and k₂ as the boundary conditions. We concluded that when modeling the internal structure of Io, it is better to use the observed value of k₂ than the moment of inertia I derived from k₂ using the Radau-Darwin formula. For the models under consideration, we calculated the Chandlerian wobble periods of Io. For the three-layer model, this period is approximately 460 days.     

The Possibility of Increasing the Efficiency of Powerful Vibroseismic Sources

Doklady Earth Sciences - A numerical parametric study of the scattering features of Rayleigh waves that appear during the operation of a vibroseismic source on near-surface inhomogeneities (seismic...     

Wave disturbances induced by crustal earthquakes: Case study of two strong earthquakes in the Caucasian-Anatolian sector of the Alpine Mediterranean mobile belt

The display conditions of strong earthquakes in the Caucasian-Anatolian sector of the Mediterranean mobile belt are analyzed with allowance for the instrumental observations by titlmeters and magnetic variometers at the North Caucasian geophysical observatory of Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences (NCGO IPE RAS) (Elbrus volcanic region) and at the magnetic stations operated by the Institute of Terrestrial Magnetism, Ionosphere, and Radio Wave Propagation (IZMIRAN). It is demonstrated that the geophysical information obtained during the preparatory stages of the earthquakes on March 8, 2010 and January 19, 2011 in Turkey and the North Caucasus, respectively, reflect the fine structure of the anomalous wave processes of the preparation and evolution of the crustal earthquakes. The results provide a general idea of the geomagnetic activity and some characteristic features of the induced anomalous disturbances in the Caucasian-Anatolian sector of the Alpine Mediterranean mobile belt, which precede and accompany strong seismic events.     

Gravimagnetic perturbations preceding earthquakes

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.     

On a class of electromagnetic disturbances preceding strong earthquakes

The results of experimental observations over variations of the Earth’s magnetic field recorded by the instruments of the North Caucasus Geophysical Observatory are presented. We observed specific ultralow-frequency quasi-oscillatory waveforms preceding strong distant seismic events in the structure of electromagnetic signals.     

On magnetic precursors of earthquakes

A simple classification is proposed for magnetic precursors of earthquakes. The high-latitude observations of the so-called Big Magnetic Pulses (BMP)—isolated high-amplitude magnetic pulses that sporadically arise against the undisturbed magnetic background—are used for searching for a probable correlation between BMPs and earthquakes. It is shown by the superposed epoch analysis that seismic activity slightly increases after BMPs. A wide maximum in the number of the earthquakes is observed within the first hour after the BMP. Thus, probably, a new type of magnetic precursors has been found. However, the mechanism of the relationship between BMPs and earthquakes remains open to discussion.     

Recent Tectonic Rupturing on the Mud Volcano of Mount Karabetova,Taman Peninsula

Doklady Earth Sciences - In October 2019, extremely impressive, fresh ruptures of the surface on the mud volcano of Mount Karabetova were discovered. The ruptures are represented by all the main...