16:45 〜 17:00
[SSS06-12] Detection and location of seismovolcanic signals at Mutnovsky and Gorely volcanoes using seismic network-based methods
キーワード：Kamchatka volcanoes, seismovolcanic tremors, cross-correlation methods, network-based methods
Volcanic eruptions and their associated activity vary significantly across different volcanic systems, generating a wide range of seismic signals. One such signal type is volcanic tremor, which may be caused by non-destructive processes within magmatic and hydrothermal systems, such as pulsations of pressurized fluids or the release of steam and gases from fumaroles. Volcanic tremors are crucial for characterizing volcanic and geothermal activity, and their detection and localization are essential for monitoring volcanoes and forecasting eruptions.
The active Mutnovsky and Gorely volcanoes, located near the city of Petropavlovsk-Kamchatsky and close to the Mutnovsky Geothermal Plant in Kamchatka, pose potential threats to both the population and infrastructure. The Kamchatka Branch of the Geophysical Survey (KB GS) of the Russian Academy of Sciences previously observed volcanic tremors beneath Gorely and Long-Period earthquakes (LP) beneath Mutnovsky. However, only a few detailed studies have been conducted on them due to the lack of dense seismic observations.
In this study, we analyzed cross-correlations of continuous seismic data from 23 temporal and permanent stations that operated between 2023 and 2024 near Mutnovsky and Gorely volcanoes. We filtered the signal in the frequency band between 0.1 and 10 Hz and selected 20-minute time windows with 50% overlap, applying both temporal and frequency normalizations. Volcanic tremors, identified within the 1.5–5 Hz frequency range, were observed from 6 February 2024 until the end of our monitoring period on 15 March 2024. Coherent signals were detected through network response functions and covariance matrix spectral width. To estimate the spatial locations of the tremor sources, we backprojected the cross-correlations using a 1D velocity model and produced a 3D spatial likelihood function. We found that the tremor sources were located up to 2 km below the surface of the northeast flank of Mutnovsky Volcano, where thermal springs and fumaroles are currently active. The tremor sources are likely linked to a hydrothermal explosion at an abandoned well that formed a large crater between February and March 2024, as reported by the staff of Mutnovsky Geothermal Plant.
The identification of volcanic tremors beneath Mutnovsky improves our understanding of the volcano's structure and ongoing processes. Furthermore, these tremors can be utilized for monitoring the activity of Mutnovsky volcano.
The active Mutnovsky and Gorely volcanoes, located near the city of Petropavlovsk-Kamchatsky and close to the Mutnovsky Geothermal Plant in Kamchatka, pose potential threats to both the population and infrastructure. The Kamchatka Branch of the Geophysical Survey (KB GS) of the Russian Academy of Sciences previously observed volcanic tremors beneath Gorely and Long-Period earthquakes (LP) beneath Mutnovsky. However, only a few detailed studies have been conducted on them due to the lack of dense seismic observations.
In this study, we analyzed cross-correlations of continuous seismic data from 23 temporal and permanent stations that operated between 2023 and 2024 near Mutnovsky and Gorely volcanoes. We filtered the signal in the frequency band between 0.1 and 10 Hz and selected 20-minute time windows with 50% overlap, applying both temporal and frequency normalizations. Volcanic tremors, identified within the 1.5–5 Hz frequency range, were observed from 6 February 2024 until the end of our monitoring period on 15 March 2024. Coherent signals were detected through network response functions and covariance matrix spectral width. To estimate the spatial locations of the tremor sources, we backprojected the cross-correlations using a 1D velocity model and produced a 3D spatial likelihood function. We found that the tremor sources were located up to 2 km below the surface of the northeast flank of Mutnovsky Volcano, where thermal springs and fumaroles are currently active. The tremor sources are likely linked to a hydrothermal explosion at an abandoned well that formed a large crater between February and March 2024, as reported by the staff of Mutnovsky Geothermal Plant.
The identification of volcanic tremors beneath Mutnovsky improves our understanding of the volcano's structure and ongoing processes. Furthermore, these tremors can be utilized for monitoring the activity of Mutnovsky volcano.