bluuebunny/crossref_metadata_2025 huggingface dataset:
Formation of the Fauna of Cartilaginous Fishes of the Emperor Seamount Chain
Authors: Dolganov V. N.
Published: April 2024

The presented data on distribution of cartilaginous fishes in the northern Pacific Ocean show that the core of the fauna of the Emperor Seamount Chain includes Indo-West Pacific species that inhabited the ridge from the coast of Asia. Epipelagic species are not permanent residents of the region, but annually migrate from the mainland to the ocean together with common abundant fish species that form their food supply. Sharks and chimaeras of the meso-benthopelagic zone constitute the basis of permanent cartilaginous fish communities of the seamounts of the Northwestern Pacific. Representatives of the lower meso-benthopelagic zone populated the Hawaiian and Emperor Seamount Chains along with the Markus-Necker Ridge. Less deep-sea, but adapted to a fairly long-term dwelling in the water column in the adult state, the species of the upper meso-benthopelagic zone, spreading towards the ridge, covered a distance of about 3000 km in the pelagic zone. Probably, some sharks of the lower meso-benthopelagic zone could inhabit the underwater mountains of the Emperor Seamount Chain in the same way. The low endemicity of cartilaginous fishes in the considered area (5%) and the presence of identical and closely related species in southern Japan do not allow us to regard migrations to the Emperor ridge as rare, with the exception of sharks of the genera Squalus and Centroscyllium, which diverged on the seamounts to the level of new species.
Dynamics of Zooplankton Consumption by the Three-speed Stickleleback Gasterosteus aculeatus (Linnaeus, 1758) at Different Densities of the Predator
Authors: Lobyrev F. S.
Published: April 2024

An experiment was set up to estimate the rate of zooplankton consumption by the three-spined stickleback Gasterosteus aculeatus (Linnaeus, 1758) at different predator densities. A differential equation describes the dynamics of zooplankton abundance depending on duration of predator feeding. The derived function accurately characterizes the rate of zooplankton consumption by stickleback in the experiment, demonstrating a good agreement between the theoretical prerequisites and the experimental results. The relationship between changing a number of prey during predation, its mortality and consumption rate was revealed. The hypothesis of consumption rate proportional to the number of predators was tested. A comparative analysis of ingestion rate as a function of time and a function of prey density was performed.
Dynamics of Phytoplankton Species Structure in the Kurile Lake (Kamchatka Peninsula)
Authors: Sukhanov V. V. , Lepskaya E. V.
Published: April 2024

The species structure of the dominant community of unicellular algae inhabiting the spawning and feeding salmon lake was studied in the Kurile Lake (southern Kamchatka peninsula). It has been shown that this structure is well described by the Motomura model. The geometric progression coefficient does not differ significantly from the value prescribed by the model, which is based on the stochastic remainder hypothesis. Several integral indicators characterizing the species structure have been calculated. The study has revealed some typical and unusual correlations between these integral indices. Inter-annual and intra-annual cyclical fluctuations in the value of indicators have been found.
Crater Lake Kipyashchee of Volcan Golovnin Caldera: Geochemistry of Water and Gases, Output of Magmatic Volitatives (Kunashir Island)
Authors: Kalacheva E. G. , Taran Yu. A. , Voloshina E. V. , Tarasov K. V. , Melnikov D. V. , Kotenko T. A. , Erdnieva D. M.
Published: April 2024

Lake Kipyashchee (Boiling) with an area of ~4.6 ha and a maximum depth of 25 m fills the explosion funnel near one of the extrusive domes of the Golovnin volcano caldera. The water of the lake is ultra-acid (рН = 2.2–2.5) of the chloride-sulfate type with a mineralization of 2.0–2.2 g/l. The water temperature on the surface varies from 30 to 100°C, the average is 37°C. The flow of the lake is carried out through the Protoka in the lake Goryachee (Hot) is 120 l/s (August 2021). The hydrothermal output of magmatic Cl and S (as SO4) from Lake Kipyashchee is 10 t/day and 5.4 t/day, respectively. For the first time, the total diffusive removal of carbon dioxide from the surface of Lake Kipyashchee was estimated as 5.4 tons/day. Obtained from the results of field work in 2020–2021 geochemical data indicate an increase (compared to 2015) in hydrothermal activity in the Golovnin volcano caldera.
Textures of Volcanites as Indicators of Dangerous Impacts of Environment (on the Example of the Late Cenozoic Volcanics of the Caucasus)
Authors: Kurchavov A. M.
Published: April 2024

Textural features of lava and ignimbrite formations indicate the high role of volatile components in their formation and the rapid release of volatile from the solidifying melt. This creates a high level of danger to the environment. Therefore, it is important to study the textures of the formed volcanites to predict the degree of danger in the event of a possible resumption of magmatic activity.
Giant Martian Volcano-Tectonic Megamorphic Structures of the Central Type and Their Probable Small Terrestrial Analogues
Authors: Melekestsev I. V.
Published: April 2024

The article shows that neither on the ground nor on the bottom of the seas there are no today topographical volcano-tectonical megamorphic structures similar in size, composition and origin to those giant morphic structures with volume of their building up rocks of 1–2.4 × 106 km3 revealed on Mars (patera Alba, Mount Olympus, Arsia, Askrian, Pavlina, Elysium). Fragments and traces of such formations have not been unambiguously revealed and described in geological strata of both Meso-Cenozoic and Paleozoic. The same applies to the older epochs of the Earth. The components of the relief of the Martian megamorphic structures are roughly similar in their form to very strongly enlarged copies of long-known and repeatedly described terrestrial volcanic structures – large shield, shield-like, and substantially lava volcanoes, lava domes, as well as calderas of different types. Although the structures of the listed types of volcanoes are not morphologically identical to their Martian analogues, they are smaller in height of their structures, and their slopes are steeper. Calderas are many times shallower. The age of Martian volcanic forms is much older. A unique formation is the megamorphic structure of Mount Olympus, which was formed in a large glacial cover, and in the formation of which the glacial processes also took a significant part. It is attributed to megamorphic structures of the giant tyuya type. Its small analogues are different in age and parameters glacial-subarctic tuyas, which suffered glaciation in the volcanic regions of the Earth.
Deep Velocity Structure and Seismicity of the Trans-Baikal Region (Along the Reference Geological and Geophysical Profile 1-SB)
Authors: Solovyev V. M. , Seleznev V. S. , Salnikov A. S. , Chechelnitsky V. V. , Gileva N. A. , Liseikin A. V. , Bryksin A. A. , Galyova N. A.
Published: April 2024

The paper presents analysis of the seismicity and deep structure of the Trans-Baikal region in the section of the reference geophysical profile 1-SB. It was determined that the Earth’s crust and upper mantle has a complex heterogeneous structure. The thickness of the Earth’s crust varies from 40 km in the South-Eastern part of the profile and in the areas of intermountain depressions in the North-Western part, and up to 48 km in the areas of mountain ranges. The values of the boundary velocities along the M boundary also vary greatly, from higher values of 8.4‒8.5 km/s for P-waves and 4.9‒4.95 km/s for S-waves (especially in the South-Eastern part of the profile) to reduced values of 7.8‒8.0 km/s for P-waves and 4.6‒4.7 km/s for S-waves in the section of the Baikal rift zone in the North-Western part of the profile. A strong inhomogeneous structure of the medium in terms of elastic wave velocities, Vp/Vs velocity ratios, and the Poisson’s ratio is determined for the upper and the middle crust at depths of 8‒20 km. The authors determined that zones of increased seismicity are referred to blocks of the Earth’s crust with inhomogeneous velocity structure according to data of differently polarized P- and S-waves. The area of the Baikal rift zone, in the immediate vicinity of the largest Muya earthquake of 1957 with M = 7.6, is characterized by elevated inhomogeneity in the upper part of the Earth’s crust according to the elastic wave velocities and secondary parameters of the medium (Vp/Vs ratio, K* = = Vp/(γ – 1), where γ = Vp/Vs, Poisson’s ratio (σ)). A number of other inhomogeneous deep zones have also been identified in the profile based on anomalies of P- and S-waves velocities and secondary parameters of the medium, which correlate to varying degrees with seismically active sites according to long-term instrumental observations. The established unambiguous connection of large inhomogeneous zones of the upper crust of the Trans-Baikal region with the accumulation of stresses and their discharge in the form of strong earthquakes allows us to make a reasonable medium-term forecast of catastrophic events.
Volcanism of the Initial Stage of Subduction of the Northern Part of the Pacific Plate (Kamchatka Peninsula, Kumroch Ridge)
Authors: Tolstykh M. L. , Babansky A. D. , Smirnova M. D. , Pevzner M. M. , Lebedev V. A. , Larionova Yu. O. , Kuscheva Yu. V. , Parfenov A. V.
Published: April 2024

We studied whole rocks compositions of the Baydara and Semkorok Mountains, which are located at the north-western part of Kumroch Ridge. Rocks are represented by Amf-Px basaltic andesites and andesites, and have microelements distribution typical for island-arc type of rocks. Some mineralogical and geochemical characteristics of the studied lavas of the Baydara Mt. (low concentrations of K2O, all REE, LILE, Th and U) and the Semkorok Mt. (low LREE concentrations) make them principally different from the rocks of the located nearby Late Pleistocene-Holocene Shiveluch volcanic massif. Isotopic K-Ar age of lavas (0.7 Ma for Baydara and 1.3 Ma for Semkorok) allow us to propose that their eruptions might be caused by the initial phase of the northern segment of the Pacific plate subduction. The Early Paleocene age (~62 Ma) of the Khapitsa series rocks, which compose north-western part of Kumroch Ridge, is confirmed for the first time by the isotopic-geological methods.
Retrospective Prediction of the Location and Intensity of Two Strong Crustal Earthquakes in Iran And India
Authors: Morozov V. N. , Manevich A. I. , Tatarinov V. N.
Published: April 2024

The paper presents the results of mathematical modeling of the stress-strain state of the epicentral zone before and after the strong earthquakes Mw = 6.4 of June 22, 2002 in the north-west of Iran in the region Qazvin and 26 January 2001 in India with M = 6.9. The method of modeling of the stress-strain state of the block elastic-isotropic heterogeneous medium disturbed by the system of faults under the influence of the external field of tectonic stresses was used, boundary conditions were set according to seismological data. It is shown that at a certain ratio between the main stresses the epicenters of strong cow earthquakes are localized in the area of high concentration of stress intensity. The development of aftershock process is caused by stress release caused by a new break, and the emerging clusters of aftershocks spatially correlate with the zone of released intensity of stresses. It is assumed that the tectonic rupture propagates in the direction of the zones of high intensity of stresses. The actual correlation between the rupture length and the earthquake magnitude from the accumulated elastic energy and its possible realization under given structural and tectonic conditions is shown.
Petrophysical and Strength Properties of Extrusive Rocks of the Bezymianny Volcano, Kamchatka
Authors: Ladygin V. M. , Girina O. A. , Frolova Yu. V.
Published: April 2024

For the first time, the results of petrophysical studies of the Bezymianny volcano extrusive rocks from dacites to andesites are presented. A comparative characteristic of the extrusive rocks properties is given according to the selected age groups. The dynamics of changes in the properties of extrusion rocks depending on their age is shown: it is established that the older the rocks, the higher the indicators of their density, strength and elastic properties. The petrophysical features of the rocks of the extrusive domes and lava flows are compared. The applicability of petrophysical properties to clarify the genesis of rocks similar in petrographic characte-ristics, in particular, of extrusive and effusive origin, is substantiated.
Conditions of Formation of Epithermal Mineralization of the Kyplatap Volcanic Field (Central Chukotka)
Authors: Volkov A. V. , Pilitsyn A. G. , Prokofiev V. Yu. , Dolomanova-Topol A. A. , Murashov K. Yu.
Published: April 2024

The article considers the geochemical features and conditions of the formation of substantially silver mineralization of the Kyplatap volcanic field (KVF), of the Chaunsky zone, of the Central Chukchi Sector, of the Okhotsk-Chukchi volcanic belt (OChVB). New data on the composition, distribution and grade of trace elements, including REE in ores, are presented. The noticeable enrichment REE of the studied samples, the predominance of light lanthanides over heavy ones, very low Eu/Sm ratios (\( \ll {\kern 1pt} 1\)), weakly inclined near–chondrite spectra with obvious Eu minima are typical for the epithermal ore-forming system of the KVF. The Ce/Ce* vary from slightly negative to moderately positive values (from 0.81 to 1.38), and the Eu/Eu* vary from 0.28 to 0.7. This combination of Ce/Ce* and Eu/Eu* indicates the oxidative conditions prevailing during ore formation. The results of thermo- and cryometric studies of fluid inclusions in quartz allowed us to establish that the ore-forming fluid contained Na, Mg and K chlorides, epithermal mineralization was deposited by homogeneous hydrothermal fluids with salt concentrations (0.3–6.2 wt. %-eq. NaCl), fluid density – 0.60–0.87 g/cm3, at temperatures from 203 to 343°C, water vapor pressure varied from 40 to 140 bar. The obtained geochemical and thermometric data confirm the assumption put forward earlier – that the studied mineralization of KVF belongs to the intermediate sulfidation epithermal class. These data point to andesite magmas and meteoric waters as the most likely sources of fluids. The information in the article is of practical importance for regional predictive metallogenic constructions, prospecting and evaluation of epithermal Au–Ag deposits.
Ebeko Volcano Activity in 2022: Mechanism and Products of Eruption
Authors: Kotenko T. A. , Smirnov S. Z. , Timina T. Y.
Published: April 2024

The paper provides information about the eruptive activity of the Ebeko volcano in 2022. From January 22 to June 13, phreatic explosions occurred in the crater lake caused by water seeping through the plug formed in the upper part of the magma channel and its boiling. On June 14, Vulcanian explosions began, destroying the lake. The granulometric composition of the ashes has changed in the direction of reducing the particle size. Petrographic and mineralogical-geochemical studies of tephra allow us to define this period as a phreatomagmatic eruption by the presence of fresh juvenile material. It is established that the interaction of magma with the waters of the hydrothermal system of the Ebeko volcano leads to its depletion with alkali metals and enrichment with silica. It is suggested that the formation of amorphous water-containing silica in the form of numerous separations and its subsequent dehydration may contribute to the explosive activity of the volcano.
Model of the Seismic Rupture Surface of the Chignik Earthquake (Alaska, USA) 07.29.2021 Based on SAR Interferometry and GNSS Data
Authors: Konvisar A. M. , Mikhailov V. O. , Volkova M. S. , Smirnov V. B.
Published: April 2024

The paper presents a new rupture model for the Mw = 8.2 “Chignik” earthquake, which occurred off the coast of the Alaska Peninsula on 29.07.2021. The model is based on the Earth’s surface displacement fields obtained by InSAR (Interferometric synthetic aperture radar) method using images of the ESA Sentinel-1 satellites from 17.07 to 10.08.2021 and data on horizontal displacements at nearest permanent GPS sites from 18.07 to 08.08.2021. Obtained displacement fields include both coseismic and part of postseismic displacements. When constructing a model of the seismic rupture surface, we used F. Pollitz’s solution of the problem of the displacement fields at the surface of a spherical radially stratified planet caused by displacements on a rectangular discontinuity located inside it. For the regularization of the inverse problem, we added the condition that the direction of slip on each element of the fault plane is close to the rake angle, determined from seismological data. In the constructed model, the seismic rupture area was approximated by a single plane with a length of 225 km along the strike, 126 km along the dip, divided into 48 identical rectangles. According to the constructed model, the type of displacements is almost pure thrust, and displacements, in general, occurred throughout all the source area. The maximum displacement was 5.7 m, with an average displacement over the entire plane of 2.2 m, which is close to the USGS and GCMT estimates derived from seismological data.
Tephra from the Island Intra-Plate-Oceanic Volcano Cumbre-Vyaha (Eruption 2021)
Authors: Silaev V. I. , Karpov G. A. , Shuisky A. S. , Khazov A. F. , Ignatiev G. V. , Shanina S. N. , Makeev B. A. , Smoleva I. V. , Kiselyova D. V.
Published: April 2024

Comprehensive mineralogical and geochemical studies of a representative sample of tephra from the Cumbre-Vyaha volcano (2020–2021 eruption), which has a gravel-psammitic granulometric composition and is characterized by an anomalously high degree of particle vesicularity, have been carried out. In terms of bulk chemical composition, this tephra corresponds to the transition from alkaline picrobasalts to alkaline basalts, differing fundamentally from the tephra ashes of marginal continental volcanoes. The studied tephra contains 45 trace elements with a total content of up to 2333 ppm, which exceeds that in the tephra of island-arc volcanoes. According to the ratio of geochemical criteria, tephra from Cumbre-Vyaha correspond to the average values for within-plate volcanoes in the oceans. The geochemical feature of the studied tephra is a strong enrichment in lanthanides, noble and platinoid metals. H2, CO, CO2, H2O, CH4, C2H4, C2H6, C3H6, C3H8 were found in the composition of the lithogenic gas phase separated by heating from the studied tephra. The proportions between inorganic components in the gas phase generally correspond to the boundary region between crustal and mantle-crustal derivatives, but a relatively low water content is found. Olivine of composition Fo73–84, essentially diopside clinopyroxene, andesine-bytovnite plagioclases, chrome spinels, phase-homogeneous solid solutions of ilmenite in magnetite, phases of Ni-Cu-bearing native iron, quartz, and sodium hydroxyl chlorides were identified and studied in microlites. In addition, dispersed carbon matter with carbon isotopic composition δ13СPDB = –30…–24‰ was found in the Cumbre-Vyaha tephra, which corresponds to the carbon isotope composition in abiogenic carbonaceous substances of volcanic origin. The totality of the results of mineralogical and geochemical studies characterizes the Cumbre-Vyaha volcano as a typical representative of within-plate oceanic plume volcanoes.
Geological Structure Features and Rocks Composition of Kronotsky Volcano, the Largest Stratovolcano in the Frontal Zone of the Eastern Volcanic Belt of Kamchatka
Authors: Gorbach N. V. , Rogozin A. N.
Published: April 2024

Based on the results of 2020‒2022 field works, this paper presents a characterization of the geological structure and whole rock composition of Kronotsky volcano, one of the poorly studied eruptive centers of the Eastern Volcanic Belt (EVB) of Kamchatka. The volume of the volcanic edifice is estimated at 350 km3, that significantly exceeds the volumes of other stratovolcanoes of the frontal zone of EVB. Rocks of a volcano are presented by low-K, high-Fe tholeiitic basalts and basaltic andesites (SiO2 = 47.04–53.15 wt %; K2O = = 0.24‒0.65 wt %; FeO*/MgO = 1.2‒2.89). The basalts show extremely low contents of silica, potassium, titanium, and phosphorus in comparison with rocks of other frontal volcanoes of Kamchatka. The revealed petrochemical features were used to clarify the belonging of the objects located at the junction of Kronotsky and Krasheninnikov volcanic edifices. The obtained data will serve as the background for further petrological and geochemical studies of the volcano, and also may be used for reconstruction the sequence of volcanic events in this area, including clarification of the history of Kronotsky Lake formation.
Properties of Magmatism, Hydrothermal-Metasomatic and Filtration-Transport Processes in Uranium-Bearing Volcanogenic Structures
Authors: Petrov V. А. , Аndreeva О. V. , Poluektov V. V.
Published: April 2024

Creation of a refined conceptual model for the formation of volcanogenic uranium deposits includes researches of the nature of magmatic, hydrothermal-metasomatic and filtration-transport processes, as well as physico-chemical conditions for the transfer and deposition of uranium. We considered these issues using the examples of the Streltsovskaya caldera and the ore field of the same name in Eastern Transbaikalia, the Xiangshan volcanic structure in South China, and the McDermitt caldera in the western United States (Oregon and Nevada states). According to the IAEA classification [Geological Classification …, 2018], these ore fields and deposits belong to the volcanogenic (volcanic-related) type. In the Streltsovsky and Xiangshan ore fields, a combination of volcanogenic in the cover and granitic (granite-related) in the basement types of deposits is observed. The main part of uranium industrial deposits of volcanic type in these regions was formed during the Mesozoic and Cenozoic epochs (although more ancient, Paleozoic, objects are known in the world). Despite different time intervals of the ore-bearing volcanogenic structures formation, many features of magmatic, hydrothermal, and filtration-transport processes in them are very similar. It is assumed that these features are due to the general influence of intraplate tectonic regimes or the evolution of the outer parts of the ocean-continent zones where magmatic activity produced volcanism of the bimodal series in the predominant sequence mafic ‒ felsic volcanics ‒ mafic, and the migration of uranium-transporting fluids was set by the joint action of seismogeodynamic and thermoconvective processes.
Quartz Porphyries of the Outer Islands of the Gulf of Finland ‒ Volcanic Comagmates of the Rapakivi Granites
Authors: Terekhov E. N. , Makeyev A. B. , Skublov S. G. , Okina O. I. , Maximova Yu. A.
Published: April 2024

The article presents new petrogeochemical data of rocks from the area of the Outer Islands of the Gulf of Finland. Previously, quartz porphyries of Gogland Island were considered as a standard of volcanic comagmates of Rapakivi granite of the Vyborg massif. There are two effusive tolshas on Sommers Island. The “Southern” is composed of quartz porphyries, with an isotopic age of 1.66 Ga old, so they can be considered as the earliest manifestations of Riphean magmatic activity in this area. In addition to quartz porphyries, trachybasalts, andesibasalts, and dacites are present in the “Northern” strata, and its isotopic age is 1.59‒1.57 Ga old, which does not correspond to the values of the nearby Vyborg massif 1.65‒1.63 Ga old. Therefore, despite the pro-ximity of the compositions of quartz porphyry and rapakivi granites, volcanites are not products of differentiation of the magma initial for granites, but were formed independently of them from the same type of source, but in a slightly different structural environment, allowing their free flow to the Earth’s surface.
Altay Seismicity Evolution after the 2003 Chuya Earthquake
Authors: Emanov A. F. , Emanov A. A. , Fateev A. V. , Shevkunova E. V. , Gladyshev E. A.
Published: April 2024

The 2003 Chuya earthquake had a noticeable impact on the seismicity of the whole Altay region. The article presents data on changes in the seismic regime of Altay from 2003 to 2021. It is shown that in the first six months after a major earthquake in 2003, earthquakes occur in the epicentral zone, and other structures of Altay are aseismic. After 2009, changes are formed both in the near zone, covering geological structures adjacent to the epicenter, such as the Aigulak, Kuray, South Chuya, North Chuya ridges, and in the far zone at distances of 250‒300 km from the epicenter and in different directions from it. After the Aigulak earthquake of 2019, an aftershock process was formed, which ensured the displacement of the center of Altay seismicity into the ridge of the same name. The explanation of the seismicity development in space and with time delays for years can be given on the basis of the influence of a large earthquake on the multi-layered lithosphere in accordance with models that assume the occurrence of disturbances during a large earthquake not only in the fragile part of the earth’s crust, but also in layers with high plasticity.
Magnetic and Ionospheric Effects of the Shiveluch Volcano Eruption on April 10, 2023
Authors: Adushkin V. V. , Riabova S. A. , Spivak A. A. , Tikhonova A. V.
Published: April 2024

Using the results of instrumental observations made at the INTERMAGNET network and at the ionospheric sounding station “Wakkanai”, it is shown that a strong eruption of the volcano Shiveluch of an effusive-explosive nature, which occurred on April 10, 2023, was accompanied by variations in the Earth’s magnetic field, as well as changes in the critical frequency of the ionosphere F2-layer.
Modeling Acoustic Processes of the Interaction of Cells of Sound-Absorbing Structures of Aircraft Engines
Authors: Pisarev P. V. , Pankov A. A. , Anoshkin A. N. , Akhunzyanova K. A.
Published: April 2024

Physical and mathematical numerical models have been developed to predict the effective acoustic properties of sound-absorbing honeycomb structures at sound pressure levels of 100 and 130 dB with normal sound wave incidence. The sound absorption coefficients and patterns of acoustic interactions of cells installed at the end of a cylindrical duct with normal sound wave incidence on them were studied by numerical mathematical and physical modeling. The sound absorption efficiency of single and groups of resonators of various shapes and sizes is estimated, and unique combinations of cells in groups are identified, taking into account their acoustic interactions. Representative samples of fragments of sound-absorbing structures were 3D-printed; laboratory tests of the samples were carried out with an interferometer with a normal sound wave incidence on the cells at a sound pressure level of 130 dB.
Changes in the Spectral Characteristics of Vowels in Russian Speech on a Noise Background
Authors: Lunichkin A. M. , Andreeva I. G. , Zaitseva L. G. , Gvozdeva A. P. , Ogorodnikova E. A.
Published: April 2024

The article studies the acoustic characteristics of Russian speech under conditions of multitalker babble noise and manifestation of the Lombard effect in the context of auditory analysis of a complex scene. We have compared the spectral characteristics of stressed vowels [a], [u], [i] in words uttered by six women in completely quiet conditions and against a background of diotically presented multitalker babble noise at a level of 60 dB, imitating polyphony. In noise conditions, versus quiet, we obtained an increase in voice fundamental frequency (F0) and the first formant (F1) for all identified vowels. No overall pattern in changes in the second formant (F2) was found. When the vowel [i] was spoken in noise conditions, F2 decreased in all speakers; when vowels [u] and [a] were pronounced, it could have both decreased and increased. Thus, in general, the nature of the revealed changes in the spectral characteristics of the vowels of Russian speech in noise conditions corresponded to the features of Lombard speech for a number of European and Asian languages. For the first time, an inversely proportional relationship between F0 of a speaker in quiet conditions and its changes in noise conditions: the higher F0 in quiet conditions, the less its increase on a noise background . The revealed spectral changes reflect the processes of adaptive articulation correction aimed at highlighting the speaker’s voice and increasing the intelligibility of his speech against the background of multitalker babble noise.
The Acoustic Center of a Measuring Hydrophone
Authors: Isaev A. E. , Khatamtaev B. I.
Published: April 2024

Various approaches to the formulation of the definition of an acoustic center of a transducer and the problems arising when using them for experimental determination of the acoustic-center position are considered. The reasons for which the formulation and the corresponding method for determining the position of the acoustic center of a microphone are not suitable for a hydrophone are discussed. An experiment is described that demonstrates the proposed method for experimentally determining the position of the acoustic center of a hydrophone during its phase calibration by the reciprocity method.
Excitation of Acoustic Modes by Tone Harmonics of a Hole in a Jet-Driven Helmholtz Oscillator
Authors: Abdrashitov A. A. , Marfin E. A.
Published: April 2024

Periodic pressure fluctuations were studied experimentally in the model of a jet-driven Helmholtz oscillator with a cylindrical chamber with a round air jet impinging on the sharp edge of the outlet. The evolution of the amplitude–frequency spectrum of the hole tone from its appearance at a jet velocity of about 2 m/s to excitation of the first acoustic resonance mode at the Helmholtz frequency was studied. The hole tone was a family of harmonics that progressively became more complex as the length and velocity of the jet increased. The successive occurrence of a family of acoustic modes on the harmonics of the jet tone with a further increase in jet velocity is studied. Modes at the Helmholtz frequency arose alternately on the harmonics of the hole tone in the gain band of the oscillator, starting from the highest harmonic. The first mode occurred at the highest harmonic; the second mode, at the previous harmonic; and so on. The final mode arose at the fundamental harmonic of the hole tone and had the maximum amplitude. With a further increase in the Reynolds number, periodic pressure fluctuations became disordered turbulent fluctuations. With a sufficient chamber size and jet velocity, azimuthal and half-wave resonances appeared at the highest harmonic of the hole tone. The largest Reynolds number at which resonance at the Helmholtz frequency was observed was 105.
Experimental Testing of the RAY Computational Program for Solving Acoustic Ranging Problems on Long Trajectories Including Shelves and Deep Seas
Authors: Burenin A. V. , Lebedev M. S. , Razzhivin V. V. , Shkramada S. S. , Morgunov Yu. N.
Published: April 2024

The results of studies of the features of the formation of pulse characteristics on the axis of an underwater sound channel in waveguides with different hydrological and bathymetric conditions of the Sea of Japan and the Sea of Okhotsk are discussed. The results of model calculations and experiments characterizing the regularities of propagation of low-frequency pulse signals in complex waveguides including shelf and deep sea for hundreds of kilometers are presented. It is shown that one of the main effects that determines long-range sound propagation in complex waveguides including the shelf and deep sea is the acoustic “landslide” effect. It is also shown that numerical modeling of the process of signal propagation from the shelf to the deep sea on acoustic traces in the Sea of Japan and the Sea of Okhotsk using the RAY program provides good convergence of the calculated and experimentally obtained impulse characteristics.
Tangential Impedance
Authors: Kanev N. G.
Published: April 2024

The problem of reflection of a plane sound wave from a rigid surface covered with dipole resonators is solved. It is shown that such a surface responds to obliquely incident waves, while the found angular dependence of the reflection coefficient cannot be obtained for surfaces whose properties are described by conventional impedance. Therefore, the concept of tangential impedance is proposed: the ratio of tangential acoustic force on a surface to its normal velocity. It is shown that the tangential impedance can be both isotropic and anisotropic; i.e., the magnitude of the latter depends on the direction of the incident wave. It is proposed to call the corresponding surfaces unpolarized and polarized. In some cases, tangential impedance can be useful for macroscopic description of complex metasurfaces.
Impact Damage Influence Investigations on the Composite Skin-Stringer Joint Fatigue Characteristics Under Conditions of Vibroacoustic Loading
Authors: Dubinskii S. V. , Sevastyanov F. S. , Kostenko V. M. , Denisov S. L.
Published: April 2024

The article presents the results of studying the fatigue characteristics of skin–stringer joints (T‑samples) made of a polymer composite material subjected to random vibroacoustic loading with a wide spectrum. Experimental data were analyzed to determine the damage initiation and growth mechanisms, as well as the criterion and failure mode for samples with and without impact damages. The effect of impact damage on the fatigue characteristics of the test samples at different impact energies and vibroacoustic loading levels is demonstrated. The main patterns of the influence of defects on the fatigue characteristics are revealed, which can be used in the future in creating computational models for damage development in structures made of the polymer composite material under vibroacoustic loading.
A Pulse Correlated Gas Flowmeter with Clamp-On Sensors
Authors: Mansfeld A. D. , Volkov G. P. , Belyaev R. V. , Sanin A. G. , Moroskin D. V.
Published: April 2024

An improved pulsed correlation gas flowmeter with clamp-on sensors for measuring gas flows in pipes has been created and studied. Such devices operate by measuring vortex motion velocity in a turbulent flow. The problems of isolating a weak useful signal that has passed through a gas against a background of interference from signals propagating along the pipe wall are discussed. A schematic of a correlation flowmeter with pulsed probing and the possibility of automatic search for a useful signal against a noise background is proposed. The operation of the flowmeter is demonstrated against the background of pipe wall vibrations and liquid droplets in the flow.
Interaction of Finite Perturbations with the Front and Singularity of the Profile of a Nonlinear Wave in a Dissipative Medium
Authors: Gusev V. A. , Rudenko O. V.
Published: April 2024

The interaction of a short pulse with three types of wave profiles in a nonlinear dissipative medium are described: a stationary shock front of finite width, a nonstationary forming front, and a “stationary” wave the profile of which contains a singularity. Exact solutions to the Burgers equation are used, which describe these interactions, as well as the symmetry properties of this equation.
Ground Tests of Rectangular Nozzle with Noise Reduction Devices on Aircraft
Authors: Belyaev I. V. , Makashov S. Yu. , Zaytsev M. Yu. , Yudin V. G. , Potapov A. V.
Published: April 2024

The importance of jet noise for prospective supersonic transport (SST) in takeoff and climb modes dictates the need to develop methods for reducing jet noise and their subsequent validation in large- and full-scale tests. This paper presents the results of Russia’s first ground acoustic tests of a rectangular nozzle with a noise suppression system, installed on a subsonic aircraft engine to demonstrate the technology. The authors studied a rectangular beveled nozzle with an ejector and screens—elements of the SST airframe. The test results were compared for three nozzle geometries: a round nozzle corresponding to measurements for the original engine without modifications, a rectangular nozzle without screens, and a rectangular nozzle with screens. It was found that when the rectangular nozzle without screens is used, there two opposite effects occur: noise amplification compared to the round nozzle for angles of observation close to the jet axis, and noise attenuation at angles of observation close to the fan rotation plane. Installing screens increases noise up to 5 dB in the low-frequency region below 150 Hz and reduces noise by 2 dB for frequencies higher than 250 Hz. Estimation of community noise in the EPNL metric showed that this rectangular nozzle with the noise suppression system has the effect of reducing community noise in comparison with the baseline round nozzle.
Validation of a Method for Determining the Modal Composition of a Tonal Sound Field in a Cylindrical Duct Based on Synchronous Measurements in the Duct and the Far Field in Absence of Flow
Authors: Ostrikov N. N. , Yakovets M. A. , Ipatov I. S. , Pankratov I. V.
Published: April 2024

A method has been developed for determining the modal composition of correlated sound modes propagating in a cylindrical duct, the peculiarity of which is that the effect of sound reflection from the open end of the duct is taken into account by numerical or analytical calculation of the reflection coefficients. This method was validated in the TsAGI AC-2 anechoic chamber, in which the sound field was created in the duct of a small-scale air intake model using 12 speakers at fixed frequencies; the modal composition was determined using 48 microphones installed flush with the duct walls, and synchronous measurements of the directivity of sound emission from the open end of the duct in the far field were carried out. In this case, on based on the found amplitudes of sound modes in the duct, the radiation characteristics in the far field were calculated using an analytical solution for sound emission from a semi-infinite cylindrical duct, the results of which were compared with the measurement results. It is shown that the amplitudes of sound modes found according to the developed method make it possible to reconstruct the far sound field characteristics with high accuracy in cases where the number of generated propagating modes in the duct does not exceed the number of installed microphones in the cylindrical array.
Mode Coupling Due to an Underwater Ice Keel in a Broad Frequency Band
Authors: Grigorev V. A. , Lunkov A. A.
Published: April 2024

Numerical simulation is used to study the possibility of remote acoustic monitoring of underwater keels in ice-covered shallow-water waveguides. A statistically average hummock for the Arctic region is considered, with a keel draft of 8 m, located in a waveguide with a depth of 40 m. It is assumed that the ridge of the hummock is perpendicular to the acoustic track, the length of which is 10 km. A point broadband source and a vertical receiving array are used, which are necessary for extracting the mode amplitudes. It is shown that mode coupling due to the keel manifests itself quite distinctly in modulation of the mode amplitudes in a broad frequency band. A methodology for analyzing this modulation by constructing cepstrograms (spectrograms from the spectrum) is proposed. The cepstrograms reveal dispersion curves corresponding to pairs of coupled modes. Then, from the location of the dispersion curves on the cepstrogram, it is possible to estimate the location of the keel on the track.
On the Question of Equal Loudness of Sounds of Different Frequencies
Authors: Zverev V. A. , Didenkulov I. N. , Golubev V. N.
Published: April 2024

Curves of equal loudness for sounds of different frequencies and auditory frequency responses are discussed. It is shown that curves of equal loudness do not describe the auditory frequency response and are applicable only to tonal signals. The auditory frequency response can adapt to the sound spectrum. For music, a broadband frequency response is formed; for speech, a frequency response with low-frequency suppression is used.
Experimental Testing of Acoustic Thermometry at the Scale of the Sea of Japan with a Receiver System Placed on the Axis of an Underwater Sound Channel
Authors: Morgunov Yu. N. , Golov A. A. , Voitenko E. A. , Lebedev M. S. , Razzhivin V. V. , Kaplunenko D. D. , Shkramada S. S.
Published: April 2024

We discuss the results obtained when performing a test acoustic-hydrological experiment in August 2022 at a marine test site from the coast of Sakhalin Island to Kita-Yamato Bank in the Sea of Japan. The methodology of preliminary studies in the water area intended for studying climatic variability of temperature regimes of the aquatic environment based on numerical modeling using the RAY computational program and the NEMO ocean hydrodynamic circulation model is presented. One of the main results is the average temperature of the marine environment calculated with high accuracy on the axis of the underwater sound channel in the Sea of Japan on the 1000-kilometer acoustic trace at the crossing of the vortex system. The shape of the measuring system and the technical and computational means and methods described in the article can be used as a basis for the organization of high-precision operational monitoring of thermodynamic processes in extended sea areas.
Modern Methods of Sound Propagation Modeling Based on the Expansion of Acoustic Fields over Normal Modes
Authors: Tyshchenko A. G. , Kozitskii S. B. , Kazak M. S. , Petrov P. S.
Published: April 2024

A review of modern methods of modeling acoustic fields based on their representation as a superposition of normal modes is presented. Most of the described methods are based on an approach to calculating mode amplitudes by solving parabolic equations of various types, both narrow-angle and wide-angle. We also consider two-dimensional methods for calculating acoustic fields, to which the above-mentioned three-dimensional approaches are reduced in the absence of dependence of the field and medium parameters on one of the horizontal coordinates. The computation of both time-harmonic acoustic fields and pulsed sound signals is discussed. A number of numerical examples are considered in which such calculations are performed taking into account three-dimensional sound propagation effects. For the first time within the framework of this approach, the calculation of particle accelerations at the pulse signal reception points, as well as the calculation of the energy density flux of the vector field were performed.
Determination of Ice Cover Parameters Using Seismoacoustic Noise
Authors: Presnov D. A. , Sobisevich A. L. , Shurup A. S.
Published: April 2024

A method for estimating ocean ice cover parameters (thickness, Young’s modulus, Poisson ratio, and density) that does not require the use of a source is proposed and tested on experimental data. To realize the approach, two single-channel seismic receivers located on the ice surface are required to record the vertical component of the oscillatory velocity of the seismic noise. The spectral-correlation analysis of the mutual correlation function of the noise registered by the receivers allows us to estimate the dispersion dependence of the group velocity of the bending-gravity wave propagating along the ice plate. The solution of the inverse problem is based on analyzing the variance of not only the group but also the phase velocity, which allows us to increase the amount of primary data. The obtained estimates of ice parameters are consistent with the results of independent observations carried out during the experiment, as well as with the estimates of other authors obtained for ice characteristics in the region of the experiment.
Determination of the Acoustic Wave Velocity and Attenuation in Liquids with Different Acoustic Impedances Using an Acoustic Interferometer
Authors: Zaitsev B. D. , Borodina I. A. , Teplykh A. A. , Semyonov A. P.
Published: April 2024

Theoretical and experimental features of using an acoustic interferometer for determining the velocity and attenuation of an acoustic wave in liquids with different acoustic impedances are studied. It is shown for the first time that the indicated impedance determines the ratio of the resonance values of the maximum and minimum transmission coefficient S12 for the same transmitter–receiver pair on the dependence of the transmission coefficient on the distance between the transducers. A methodology has been developed for determining the wave attenuation of a liquid free from the influence of “apparent” attenuation associated with the loss of part of the acoustic power to the transducers.
The Influence of the A Priori Uncertainty of the Shallow Sea Sound Channel Model on the Vertical Array Gain
Authors: Malekhanov A. I. , Smirnov A. V.
Published: April 2024

The purpose of this paper is to numerically demonstrate and comparatively analyze the critically strong and ambiguous impact of the a priori uncertainty of a shallow sea waveguide model in its main physical parameters on the output performance of model-based methods for spatial processing of multimode signals received by a vertical antenna array. The scenario is specified when a relatively weak signal of a remote underwater source is received against the background of intensive interference excited by a subsurface source (like a ship, for example) and ambient sea noise excited by wind waves. The considered array processing methods include matched-signal processing, optimal processing of the signal on the background of interference and noise, and suboptimal processing based on matched-mode array filtering of one of the signal-carrying modes with adaptive selection of its number. Quantitative estimates are obtained from above for the environment uncertainties, or model errors, with respect to the sound velocity in the water column and geoacoustic parameters of the underlying bottom, at which the array gain loss does not exceed a given level. It is shown that such estimates are very different both for different environmental parameters and for processing methods, with the determining role played by the conditions of useful signal reception, namely, the modal composition and intensity levels of the interference and sea noise at the array input. The problem statement and results are considered to be useful to detail the requirements for operational oceanography tools designed to support the effective operation of sonar antenna systems in real sea environments.
The Ability to Detect Sound Scattering Layers by Interferometric Side-Scan Sonar
Authors: Kaevitser V. I. , Krivtsov A. P. , Smolyaninov I. V. , Elbakidze A. V.
Published: April 2024

A method and algorithm for remote detection of sound-scattering layers in the seas and oceans using strip survey data of the bottom topography by interferometric side-scan sonar (ISSS) is considered. Based on mathematical modeling of phase-difference measurements of ISSS for multilayer scattering planes in seawater, we demonstrate the possibility of detecting sound-scattering layers and measuring their depths using the proposed algorithm. The accuracy of calculating the depths of sound-dispersing layers at a constant value of the sound velocity has been evaluated and the requirements to the ISSS have been determined to ensure the necessary accuracy of detection of individual layers located at different depths. The efficiency of the proposed method is demonstrated based on the example of processing by the developed algorithm of the experimental data obtained during bottom relief studies with an 85 kHz range ISSS.