The paper describes a planetary laser interferometric seismoacoustic observatory consisting of six stationary unequal arm laser strainmeters. Based on the triangulation method, the fundamentals of direction finding of various infrasound disturbances at any planetary distance have been developed. The authors show that in addition to determining locations of the occurrence of the recorded disturbance, using data from spatially separated laser strainmeters, it is possible to determine the nature of these signals’ divergence and, also, the loss of their energy in the propagation medium. The creation of the planetary laser interferometric seismoacoustic observatory, consisting of five stationary single-coordinate laser strainmeters and one two-coordinate laser strainmeter, united into a single measuring network with an accurate time clock TRIMBLE 5700 that is capable of recording displacements on their bases with an accuracy of 10 pm in the frequency range from 0 (conventionally) to 1000 Hz and two auxiliary laser strainmeters, will allow us to determine, at any planetary distance, the primary source of deformation infrasound disturbances with primary amplitudes from 100 nm.

Взрывное извержение вулкана Хунга-Тонга-Хунга-Хаапай 15 января 2022 г. в 04:02 UTC привело к генерации ковулканических ионосферных возмущений, распространившихся на большие расстояния. С использованием ГНСС-данных, полученных на постоянно действующих станциях сети IGS и станциях, расположенных на территории Приморского края, выполнен поиск и анализ ионосферных возмущений над территорией Приморского края и смежных районов. Скорость зафиксированных над Приморским краем ковулканических ионосферных возмущений достигла ~340 м/с, а средняя амплитуда составляла ~1.0 TECU. Также выполнено сравнение результатов, полученных по ГНСС-данным, с результатами экспериментальных данных, полученных лазерными деформографами (ориентированными по направлениям «север – юг» и «восток – запад») и лазерным нанобарографом, установленными на мысе Шульца (Приморский край РФ). В результате выполненного сравнения были обнаружены временные задержки между моментами фиксации возмущений в тропосфере и ионосфере. Величина задержки между первыми пиками возмущений составила ~50 мин.

This study considers seismoacoustic wave propagation through the land–sea interface, i.e., in the presence of a coastal wedge, taking into account the real bottom bathymetry. It is of interest in the problems of coastal monitoring and environmental studies. An effective numerical model based on the finite element method is proposed and implemented. An approximate analytical solution in the fluid and an asymptotic analytical solution for the surface seismic wave on the shore are considered to validate the numerical model. It is shown that in field experiment conditions the hydroacoustic signal generated by an underwater source with a power of ~200 W is transformed into a seismic wave on the shore with an amplitude of units of nanometers at distances of several kilometers, which can be measured by a sensitive sensor. An extensive series of numerical simulations with different model parameters was performed, which allowed us to evaluate the most appropriate propagation medium parameters to match the observed and calculated data.

This paper describes the design and principle of operation of a 20 m laser strainmeter of unequal-arm type created on the basis of a Michelson interferometer and frequency-stabilized helium–neon laser. The interferometry methods used allow the measurement of the displacement of an Earth’s crust section on the base of the laser strainmeter with an accuracy of 30 pm in the frequency range from 0 (conventionally) to 1000 Hz. This laser strainmeter, when connected to an accurate time system providing an accuracy of 1 μs, should structurally become a part of the laser interferometric seismoacoustic observatory, consisting of spatially separated laser strainmeters installed in various regions of Russia.

ГИДРОСФЕРНЫЕ КОЛЕБАНИЯ ВЫЗВАННЫЕ НАГРУЖАЮЩИМ ВОЗДЕЙСТВИЕМ АТМОСФЕРЫ, ВО ВРЕМЯ ИЗВЕРЖЕНИЯ ВУЛКАНА ХУНГА-ТОНГА-ХУНГА-ХААПАЙ - Долгих, Г.И., Болсуновский, М.А., Долгих, С.Г., Будрин, С.С.

The paper presents the data and the results of their analysis, which confirm the theory of an anomalous displacement of the upper layer of the earth's crust having a tsunamigenic character. The data were obtained from three laser strainmeters, located at the MES POI Far Eastern Branch of the Russian Academy of Sciences "m. Schultz", which registered focal disturbances caused by the tsunamigenic earthquake on July 29, 2025, as well as the deformation anomaly of the seabed that caused the tsunami in the Pacific Ocean.