TY - JOUR

T1 - An awakening magmatic system beneath the udina volcanic complex (Kamchatka)

T2 - Evidence from seismic unrest of 2017–2019

AU - Kugaenko, Yu A.

AU - Saltykov, V. A.

AU - Koulakov, I. Yu

AU - Pavlov, V. M.

AU - Voropaev, P. V.

AU - Abkadyrov, I. F.

AU - Komzeleva, V. P.

N1 - Funding Information: The study was carried out as part of government assignment to the Geophysical Survey of the Russian Academy of Sciences (project No. 0152-2018-006) and was supported by grants 18-55-52003 MNT-a and 19-05-00204-a from the Russian Foundation for Basic Research. The data used in the work were obtained with large-scale research facilities «Seismic infrasound array for monitoring Arctic cryolito-zone and continuous seismic monitoring of the Russian Federation, neighbouring territories and the world» (https:// ckp-rf.ru/usu/507436/). Publisher Copyright: © 2021, V.S. Sobolev IGM, Siberian Branch of the RAS. Copyright: Copyright 2021 Elsevier B.V., All rights reserved.

PY - 2021/2

Y1 - 2021/2

N2 - The Udina volcanic complex located in the southeastern part of the Klyuchevskoy group of volcanoes in Kamchatka remained dormant for several thousand years, but the magmatic system beneath the area may be awakening judging by seismic unrest. Seismicity in the area is characterized by data from permanent regional seismic stations and campaign local stations, as well as by data of the Kamchatka earthquake catalog. Seismic activity having nucleated at shallow depths in the vicinities of the Udina volcanoes since October 2017 may reflect a beginning cycle of volcanism. The earthquakes are mainly long-period (LP) 0.5–5 Hz events, which are commonly attributed to the movement of viscous magma and resonance phenomena in magma conduits. Such earthquakes may be a response to inputs of new magma batches to the plumbing system that feeds the volcanoes and thus may be precursors of volcanic unrest. Seismic campaigns of May–July 2018 near the Udina complex provided more rigorous constraints on earthquake coordinates and origin depths and showed that most of the earthquakes originated within 5 km beneath the Bolshaya Udina Volcano. Seismic tomographic inversion using the LOTOS code revealed a zone of high P-wave velocities, low S-wave velocities, and a high vP/vS ratio directly beneath the volcano. Such a combination of parameters typically occurs in active volcanic areas and marks intrusion of partially molten magma and/or liquid fluids. The velocity anomaly detected in 2018 is shallower than that recovered in 2014–2015. The seismic evidence, along with the available geological and geophysical data, record the movement of viscous magma related to the Udina feeding system in the middle crust, which is implicit proof for connection between the intermediate crustal and deep mantle magma sources renewed after a long lull.

AB - The Udina volcanic complex located in the southeastern part of the Klyuchevskoy group of volcanoes in Kamchatka remained dormant for several thousand years, but the magmatic system beneath the area may be awakening judging by seismic unrest. Seismicity in the area is characterized by data from permanent regional seismic stations and campaign local stations, as well as by data of the Kamchatka earthquake catalog. Seismic activity having nucleated at shallow depths in the vicinities of the Udina volcanoes since October 2017 may reflect a beginning cycle of volcanism. The earthquakes are mainly long-period (LP) 0.5–5 Hz events, which are commonly attributed to the movement of viscous magma and resonance phenomena in magma conduits. Such earthquakes may be a response to inputs of new magma batches to the plumbing system that feeds the volcanoes and thus may be precursors of volcanic unrest. Seismic campaigns of May–July 2018 near the Udina complex provided more rigorous constraints on earthquake coordinates and origin depths and showed that most of the earthquakes originated within 5 km beneath the Bolshaya Udina Volcano. Seismic tomographic inversion using the LOTOS code revealed a zone of high P-wave velocities, low S-wave velocities, and a high vP/vS ratio directly beneath the volcano. Such a combination of parameters typically occurs in active volcanic areas and marks intrusion of partially molten magma and/or liquid fluids. The velocity anomaly detected in 2018 is shallower than that recovered in 2014–2015. The seismic evidence, along with the available geological and geophysical data, record the movement of viscous magma related to the Udina feeding system in the middle crust, which is implicit proof for connection between the intermediate crustal and deep mantle magma sources renewed after a long lull.

KW - Bolshaya Udina and Malaya Udina volcanoes

KW - Long-period earthquakes

KW - Magmatic system

KW - Seismic activity

KW - Seismic tomography

KW - Seismicity

KW - Volcano

UR - http://www.scopus.com/inward/record.url?scp=85106314419&partnerID=8YFLogxK

UR - https://www.elibrary.ru/item.asp?id=46076310

UR - https://www.mendeley.com/catalogue/f6de4f2d-5cde-3da3-b96f-4465f208b701/

U2 - 10.2113/RGG20194098

DO - 10.2113/RGG20194098

M3 - Article

AN - SCOPUS:85106314419

VL - 62

SP - 223

EP - 238

JO - Russian Geology and Geophysics

JF - Russian Geology and Geophysics

SN - 1068-7971

IS - 2

M1 - 5

ER -