Probabilistic Estimates of Hypocenters from the Data of Kamchatka Seismic Network Stations

Дрознин, Д. В.; Droznina, S.; Senyukov, S.; Chebrov, Danila; Shapiro, N. M.; Shebalin, P.

doi:10.1134/s1069351319040049

Cited by 5 publications

(1 citation statement)

References 17 publications

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“…Most of the stations of the network are installed in the Kamchatka peninsula and are located west of the Kuril‐Kamchatka trench. With such one‐sided station coverage, the hypocenter locations for earthquakes in the shallow part of the Benioff zone are subject to significant trade‐offs between the lateral position and the depth with the errors in the letter reaching a few tens of kilometers (Droznin et al., 2019). KBGS RAS does not provide earthquake focal mechanisms in their catalog.…”

Section: Seismicity Observationsmentioning

confidence: 99%

The 2013 Slab‐Wide Kamchatka Earthquake Sequence

Rousset

Campillo

Shapiro

et al. 2023

Geophysical Research Letters

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Studies of initiation of large earthquakes are usually focused on frictional instabilities occurring in the near vicinity of the future rupture. Possible contributions of long‐distance interactions with large‐scale tectonic instabilities remain unknown. Here we analyze seismic catalogs and geodetic time series during a few months preceding the 2013 M = 8.3 deep‐focus Okhotsk earthquake. This deep‐focus event is preceded by four intense seismic clusters in the seismogenic zone. GNSS time series in Kamchatka revealed a transient landward motion episode 1 month prior to the mainshock, consistent with an increase of seismogenic zone loading. This transient loading episode is accompanied by a doubling of the intermediate depth seismicity rate suggesting a transient slab pull as the origin. These observations question the constant subducting velocity hypotheses and may have implications in the understanding of the long‐distance along‐slab stress interactions and in their contribution to initiation of large deep‐focus earthquakes.

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Section: Seismicity Observationsmentioning

confidence: 99%

The 2013 Slab‐Wide Kamchatka Earthquake Sequence

Rousset

Campillo

Shapiro

et al. 2023

Geophysical Research Letters

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An Awakening Magmatic System beneath the Udina Volcanic Complex (Kamchatka): Evidence from Seismic Unrest of 2017–2019

Kugaenko

Салтыков

Koulakov

et al. 2021

Russian Geology and Geophysics

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—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.

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