The M w 4.3 January 17, 2014, earthquake: very rare seismic event on the Siberian platform

Abstract

Abstract:We have studied the structural geology and geomorphology of the fault zones in the junction area of the Angara-Lena uplift and the Predbaikalsky trough. We have analyzed faults and folds and reconstructed paleostresses for this junction area named the Irkutsk amphitheatre. Our study shows that syn-fold (Middle Paleozoic) faults include thrusts, reverse faults and strike-slip faults with reverse components, that occurred due to compression from the neighbouring folded region. Recently, contrary to compression, faulting took place under the conditions of extension of the sedimentary cover: most of these recent faults have been classified as normal faults. In the Late Cenozoic, the platform cover was subjected to brittle and partly plicative deformation due to the NW-SE-trending extension that is most clearly observed in the adjacent Baikal rift. Thus, the divergent boundary between the Siberian block of the North Eurasian plate and the Transbaikalia block of the Amur plate is a zone of dynamic influence, which occupies the area considerably exceeding the mountainous region on the Siberian platform. Important factors of faulting are differentiated vertical movements of the blocks comprising the platform. Such vertical movements might have been related to displacements of brine volumes. In the Late Cenozoic basins, movements along separate faults took place in the Late Pleistocene -Holocene.Key words: Siberian platform; Late Cenozoic stress state; active fault; kinematics GEODYNAMICS & TECTONOPHYSICS P U B L I S H E D B Y T H E I N S T I T U T E O F T H E E A R T H ' S C R U S T S I B E R I A N B R A N C H O F R U S S I A N A C A D E M Y O F S C I E N C E S R e c e n t G e o d y n a m i c s RESEARCH ARTICLEReceived: May 12, 2016 Revised: November 7, 2016 Recommended by S.V. Rasskazov (Guest Editor) Accepted: December 15, 2016For citation : Sankov V.A., Parfeevets A.V., Miroshnichenko A.I., Byzov L.M., Lebedeva M.A., Sankov A.V., Dobrynina А.А., Kovalenko S.N., 2017. Late Cenozoic faulting and the stress state in the south-eastern segment of the Siberian platform.

Tectonophysical approach to the analysis of geological and geophysical data on gas-condensate deposits with the complex platform cover

“…двух платформенных землетрясений (26.02.1996 г., К=11.6, и 17.01.2014 г., К=13.3 [Melnikova, Radziminovich, 1998;Seredkina et al, 2015]) позволяет за-ключить, что ось максимального горизонтального сжатия современного поля напряжений на уровне средней части коры в пределах Иркутского амфи-Рис. 14.…”

Late Cenozoic faulting and the stress state in the south-eastern segment of the Siberian platform

“…Механизмы очагов землетрясений по [Solonenko et al, 1993;Melnikova, Radziminovich, 1998;Seredkina et al, 2015] показаны проек-циями верхней полусферы. Цифрой 1 отмечен фокальный механизм землетрясения 26.02.1996 г.…”

“…The earthquake focal mechanisms from [Solonenko et al, 1993;Melnikova, Radziminovich, 1998;Seredkina et al, 2015] are shown as the upper hemisphere projections. Earthquake focal mechanisms: 1 -26.02.1996 earthquake (K=11.6), 2 -17.01.2014 earthquake (K=13.3) that occurred within the Siberian platform.…”

“…Второе определе-ние сделано для землетрясения 17.01.2014 г. (К=13.3), эпицентр которого расположен северо-западнее [Seredkina et al, 2015] (рис. 11, диаграмма 2).…”