EGU2020-12963
https://doi.org/10.5194/egusphere-egu2020-12963
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Hydro-isotopic (234U/238U) zoning of groundwaters in the seismically active southern margin of the Siberian craton, Russia

Sergei Rasskazov1,2, Eugene Chebykin1,3, Aigul Ilyasova1, and Irina Chuvashova1,2
Sergei Rasskazov et al.
  • 1Institute of the Earth's crust, Russian Acadimy of Sciences, Irkutsk, Russian Federation (rassk@crust.irk.ru)
  • 2Irkutsk State University, Irkutsk, Russian Federation
  • 3Limnological Institute SB RAS, Irkutsk, Russia

The southern margin of the Siberian craton, which experienced severe tectonic deformations in the Neoproterozoic-Cambrian and Jurassic, is currently a part of the Baikal seismic belt. In groundwater budget of the area, the main contribution is provided by the homogeneous South Baikal reservoir (SBR) with 234U/238U activity ratio (AR) 1.95–1.99 and U concentration 0.44–0.46 µg/L. Lateral penetration of the SBR water from the hydrostatically loaded deeper part of the lake (1000 m and more) to the adjacent Siberian craton area is promoted by gentle ruptures of the Angara thrust fault and sub-vertical shear fissures of the Main Sayan suture zone. In order to predict the time and place of a strong earthquake, AR are determined in groundwater from craton basement and sedimentary cover in an area from Lake Baikal to Irkutsk. AR values associated with deformational (Cherdyntsev–Chalov) effect vary from 1.0 to 3.5. Chemical impacts in evaporates result in AR values as high as 16. Data of a 7-year monitoring show key points in AR variations that might be used for prediction of a future strong earthquake.

This work is supported by the RSF grant 18-77-10027.

How to cite: Rasskazov, S., Chebykin, E., Ilyasova, A., and Chuvashova, I.: Hydro-isotopic (234U/238U) zoning of groundwaters in the seismically active southern margin of the Siberian craton, Russia, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12963, https://doi.org/10.5194/egusphere-egu2020-12963, 2020

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