Crust and Mantle of the Baikal Rift Zone From P- And S-Wave Receiver Functions

Vinnik, Lev; Oreshin, Sergey; Tsydypova, L. R.; Мордвинова, В. В.; Kobelev, M.M.; Khritova, Mariya; Тубанов, Ц. А.

doi:10.5800/gt-2017-8-4-0313

Cited by 12 publications

(2 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The roof of the conducting asthenospheric layer is visible at a depth of 70-80 (layer I in Fig. 4), as well as determined in a seismic section (Vinnik et al 2017) and by the gravimetric method (Petit and Déverchère 2006). Basalt fluid, probably existing in this zone as a result of partial mantle matter melting, at temperatures from 1100° C and higher, can be a source of such chemical elements as hydrogen, fluorine, chlorine and sulfur, which play a big role in geodynamic processes.…”

Section: Fluid Saturation State and Rheological Lithosphere Propertie...mentioning

confidence: 53%

Influence of crustal fracturing on the thermal springs and earthquake swarms distribution in the north-east part of the Baikal rift system (Russia)

Novopashina

Kuzmina

2019

AS-ITJGW

View full text Add to dashboard Cite

The Baikal rift system faults, having developed in the recent rift formation period, are characterized by hydrothermal and seismic activity. Especially in the northeastern part, the level of fracturing affects the localization of thermal outlets and the distribution of earthquake swarms. The specific features of the hydrothermal outputs and seismicity interposition, depending on the fracture heterogeneity and water saturation of the lithosphere layers, have not been previously evaluated. The results of the statistical analysis of the hydrothermal data, presented herein, show that most of the springs are distributed in areas of increased fault density. Multiple less hot hydrotherms are associated with zones of maximum density in the inter-block space. The spatio-temporal analysis of seismicity showed that migrations of weak and moderate seismic activity propagate from earthquake swarms through these zones. Swarms initiate the deformation front by propagating in the quasiplastic layer of the upper mantle at a speed of tens of kilometers per year, which can increase the aqueous fluid pore pressure in the lower earth’s crust, facilitate the movement of the fluid upwards along the section, and cause a process of successive stress relaxation in zones of high fracturing and concentration of hydrothermal springs. Earthquake swarms occur in areas of about average fracture density, associated with deep faults framing consolidated blocks of the earth’s crust. The hydrotherms with high or average temperature, and with probable deep source chemical composition components are related with such zones.

show abstract

Section: Fluid Saturation State and Rheological Lithosphere Propertie...mentioning

confidence: 53%

Influence of crustal fracturing on the thermal springs and earthquake swarms distribution in the north-east part of the Baikal rift system (Russia)

Novopashina

Kuzmina

2019

AS-ITJGW

View full text Add to dashboard Cite

show abstract

“…The appearance of such phases in the time interval between 40 and 60 s requires strong reflecting boundaries at depths exceeding 100 km. However, the inversion of the P-and S-wave receiver functions for the stations in the BRZ (Vinnik et al, 2017) failed to detect such boundaries. The considered phases at the stations of the BRZ are represented by simple pulses that are unusual for the waveforms of multiple reflections.…”

Section: Analysis Of the Prfs: Methods And Resultsmentioning

confidence: 96%

Mantle Structure and Processes in Transition Zone of the Baikal Rift Zone

Vinnik

Oreshin

Makeyeva

et al. 2022

Izv., Phys. Solid Earth

Self Cite

View full text Add to dashboard Cite

The velocity structure of the mantle under the Baikal Rift Zone (BRZ) is investigated with the P‑wave receiver functions (PRFs) for a group of 10 seismograph stations. The BRZ presents one of the world’s most active continental rift zones. The peculiarities of the BRZ include Cenozoic magmatism in the upper mantle of the southwestern part of the BRZ, which disappears in the central and northeastern parts. The analysis of seismic data reveals other indications of the significant lateral heterogeneity of the mantle beneath the BRZ. At half of the stations there is evidence of a sharp rise of the S velocity with depth at a depth of around 330 km, similar to the descriptions for the “X” or the “300-km” discontinuity. In the central and northeastern regions at depths from about 350 to 410 km there is a well pronounced low S velocity layer, which is practically missing in the southwestern part. The origin of this layer is apparently related to the upwelling and dehydration of wadsleyite in the transition zone. At depths from 500–600 to 660 km in the central and northeastern regions there is another low velocity layer that may be explained by the accumulation of garnetite in the process of subduction of the lithosphere of the Pacific. This layer is poorly pronounced in the southwestern region. The difference between the travel times of the P410s and P660s seismic phases (differential time) in the southwestern region (23.5 s) is close to the data for the standard model (Kennett, Engdahl, 1991). In the central and northeastern regions, the observed differential time is larger than the nominal time by 1.0 s. The rise of the differential time may be related to the cooling and/or hydration of the transition zone by the slabs of the subducted oceanic lithosphere. The obtained seismic data suggest a large role of processes of hydration and dehydration in the central and northeastern regions, however, this role is comparatively small in the southwestern region.

show abstract