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Paleoearthquakes of Russian Kareliaстатья
- Автор: Shvarev S.V.
- Журнал: Doklady Earth Sciences
- Том: 519
- Номер: Suppl.1
- Год издания: 2024
- Издательство: Maik Nauka/Interperiodica Publishing
- Местоположение издательства: Russian Federation
- Первая страница: 40
- Последняя страница: 57
- DOI: 10.1134/S1028334X24604863
- Аннотация: The Russian Karelia is a region that stretches along the Eastern periphery of the Fennoscandiancrystal shield in the transition zone to the Russian plate. The main features of the topography are due to exposureof basement rocks that were subjected to processes of mainly subaerial denudation throughout almost theentire Phanerozoic. General irregularities of the relief are connected to the geologic structure and associatedwith an arc-shaped stage along the edge of the shield (“Polkanov flexure”) on which radially superimposedRiphean grabens, rejuvenated in the process of neotectonic activation and remain active until now. Structuraland tectonic features of the terrain were the basis for an exogenous transformation of the terrain as a result ofPleistocene glaciation and post-glacial development of the territory: the distribution of zones of glacial denudationand accumulation, the spread of marine and lake basins, the formation and reorganization of the rivernetwork. Periodical changes of glacial and interglacial epochs determined vertical fluctuations of the surfaceunder glacial load and after its removal with an amplitude of several hundred meters. The vertical movementvector is supplemented by the horizontal one, probably under the influence of spreading processes in theAtlantic Ocean floor. Reaching the surface of a rigid basement under conditions of vertical and horizontalstresses caused the reflection of the block-and-break structure in the topography and differentiated displacementsalong the faults, which were manifested in the form of strong earthquakes. Evidence of strong earthquakesare observed throughout the territory of Fennoscandia, although the problem of post-glacial seismicity,its spatial and temporal parameters and causes remains debatable. Numerous paleoseismic manifestationswere found in the relief and underlying substrate-rock and loose deposits of the Russian Karelia: cracks, ruptureswith vertical and horizontal displacements, rockfalls and landslides, lateral displacements of rockblocks, textures of liquefaction, injection dykes, traces of fluidization, mud- and water-stone flows. The ageof the discovered paleoseismic deformations varies mainly from the Late Glaciation to the Late Holocene,although there are traces of earlier earthquakes. The impact of earthquakes on the development of nature inthe Late Neopleistocene and Holocene is underestimated: strong earthquakes could trigger significant transformationsof the hydrographic network and landscapes.
- Добавил в систему: Шварев Сергей Валентинович