Based on of experimental data obtained during almost 30 years period at the Kamchatka volcanic eruptions, acoustic signals in the range of 1,0-10 Hz are considered, generated immediately during the magma disebaige onto the surface due to its degassing. It is shown that the acoustic signals from this range generated by volcanic eruptions are weak shock airwaves in the nearby zone. They can be divided based on their of its impulse form and statistical parameters in to 6 types associated with different unsteady processes conditioned by magma degassing. The crater dimensions control the characteristic time of pulse of surplus pressure of volcanic shock airwaves. Acoustic signals contain information about eruption dynamics and crater geometry modifications, on the examples of terminal and lateral eruptions of the Kluchevskoi volcano in May-June, 1983. The author made estimations of explosive gas amount for three strombolian type eruptions, using acoustic signals parameters. Basis for a scientific direction – volcanic acoustics – is established.
The book is of special interest for specialists in volcanology, atmosphere acoustics and explosions.

В течение 1997-1999 гг. вблизи вулкана Карымский (∆ = 1.5 км) в рамках Российско-Американской экспедиции (начальник экспедиции с Российской стороны А.Ю. Озеров, научный руководитель Е.И. Гордеев) проводились комплексные наблюдения за сейсмическими и инфразвуковыми волнами, сопровождавшими эксплозивную активность вулкана. Регистрация сигналов осуществлялась цифровой аппаратурой с частотой дискретизации сигнала 125 Гц, амплитудно-частотные характеристики аппаратуры и ее калибровка приведены в работе [13]. В данной статье сделан предварительный анализ особенностей генерации акустических сигналов (АС) в атмосфере, сопровождавших эксплозивную деятельность вулкана.

The article presents new data from field observations at Karymskiy in August 2012, which were carried out by a complex of equipment allowing recording infrasonic fluctuations, aerodynamic noise and intensity of the atmospheric electric field and volumetric activity of underground radon. It is shown that integrated geophysical observations are quite informative to monitor explosive volcanic activity. The analysis of wave disturbances in the atmosphere (the aerodynamic noise, air shock waves) and seismic events accompanying the fragmentation of magma allow us to get an insight about the physics of the explosive process. The dynamics of volumetric activity of radon near to Karymskiy is correlated to the activity of the volcano, which indicates the perspective of such observations.

After a short period of quiescence, in February 2019, Karymsky volcano (Kamchatka Peninsula, Russia) became active. During the month, a large number of moderate explosions were recorded, some of which were preceded with some periodicity by long-period earthquakes with a high degree of similarity of waveforms. The duration of the multiplet events that preceded the explosions ranged from 4 to 70 minutes. The period between earthquakes decreased as the multiplets developed. The amplitude of earthquake records either increased or remained at the same level. The multiplets with higher amplitude of earthquake records preceded the strongest eruptions. The decreasing period between earthquakes is most likely related to the acceleration of magma ascent and an increase in gas pressure in the volcanic channel. If this is true, the absence of long-period earthquakes after the eruption marks a complete release of gas pressure in the volcanic edifice.