Details

Autor(en) / Beteiligte

• Soubestre, J.
• Seydoux, L.
• Shapiro, N. M.
• Rosny, J.
• Droznin, D. V.
• Droznina, S. Ya
• Senyukov, S. L.
• Gordeev, E. I.

Titel

Depth Migration of Seismovolcanic Tremor Sources Below the Klyuchevskoy Volcanic Group (Kamchatka) Determined From a Network‐Based Analysis

Ist Teil von

• Geophysical research letters, 2019-07, Vol.46 (14), p.8018-8030

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2019

Quelle

Access via Wiley Online Library

Beschreibungen/Notizen

• We present a method for automatic location of dominant sources of seismovolcanic tremor in 3‐D, based on the spatial coherence of the continuously recorded wavefield at a seismic network. We analyze 4.5 years of records from the seismic network at the Klyuchevskoy volcanic group in Kamchatka, Russia, when four volcanoes experienced tremor episodes. After enhancing the tremor signal with spectral whitening, we compute the daily cross‐correlation functions related to the dominant tremor sources from the first eigenvector of the spectral covariance matrix and infer their daily positions in 3‐D. We apply our technique to the tremors beneath Shiveluch, Klyuchevskoy, Tolbachik, and Kizimen volcanoes and observe the yearlong preeruptive volcanic tremor beneath Klyuchevskoy from deep to shallow parts of the plumbing system. This observation of deep volcanic tremor sources demonstrates that the cross‐correlation‐based method is a very powerful tool for volcano monitoring. Plain Language Summary Volcanic tremors are the seismic signature of magmatic and hydrothermal fluids passing through volcanic conduits. Locating them in 3‐D is of real interest because it could allow us to monitor in more detail movements of magma inside volcanic edifices and, in some cases, to forecast eruptive episodes. The location of tremor in 3‐D nevertheless remains challenging because signals generated by tremors do not present any clear onset that could be used for picking arrival times and for determining source location. We design a method based on cross correlations that recovers the differential travel times between receivers of a seismic network from the analysis of the statistically dominating waves in the wavefield. We present an application of the proposed method to volcanoes in Kamchatka, Russia, and show that we can track the preeruptive tremor episode in depth before the main eruption of the Klyushevskoy volcano. Key Points A seismic network‐based method for the automatic 3‐D location of volcanic tremors is developed The migration of deep volcanic tremor sources to the surface is tracked in time beneath Klyuchevskoy volcano The developed location method is fully automatic and can be updated continuously with new data