Abstract <p>Structural features of the Yukki-Toksovskaya strike-slip fault zone are examined. Satellite imagery analysis of the Yukki-Toksovskaya zone provides a new perspective on the recent tectonics and geology of the region. Data demonstrate the shape of the lenticular shear zone, atypical for the platform area. Bodies of giant tectonic breccia in the form of rhombohedrons, unusual for this region, are mapped within the fault zone. The Yukki-Toksovskaya zone is studied using structural analysis methods at the level of fault axes and fault planes. Outcrops of Upper Quaternary rocks located on the fault axes or their limbs are described. Strike-slip faults and thrust faults are identified in the near-surface part of the Upper Quaternary sedimentary section. Kinematic types of faults are substantiated by studying the position of thrust faults on their limbs. A spectral seismic profile across a paleoseismogenic scarp and one of the faults is presented. The magnitudes of vertical and horizontal fault movements are measured based on the displacement of rocks in the marker horizon. The vertical fault planes are studied, revealing their genetic relationship with thrust faults as the development of a single shear zone. Several types of shear fault zones are identified. The Yukki-Toksovskaya zone faults are identified as sinistral strike-slip faults. A preliminary estimate of horizontal movement rates along the faults in the Yukki-Toksovskaya zone is made. It is proposed to use the Yukki-Toksovskaya fault zone territory as a testing ground for studying Holocene paleoearthquakes.</p>

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Identification of Strike-Slip Faults and Thrust Faults of the Yukki-Toksovskaya Fault Zone in the Vicinity of St. Petersburg Based on Remote Sensing Data

  • S. N. Nevolin

摘要

Abstract

Structural features of the Yukki-Toksovskaya strike-slip fault zone are examined. Satellite imagery analysis of the Yukki-Toksovskaya zone provides a new perspective on the recent tectonics and geology of the region. Data demonstrate the shape of the lenticular shear zone, atypical for the platform area. Bodies of giant tectonic breccia in the form of rhombohedrons, unusual for this region, are mapped within the fault zone. The Yukki-Toksovskaya zone is studied using structural analysis methods at the level of fault axes and fault planes. Outcrops of Upper Quaternary rocks located on the fault axes or their limbs are described. Strike-slip faults and thrust faults are identified in the near-surface part of the Upper Quaternary sedimentary section. Kinematic types of faults are substantiated by studying the position of thrust faults on their limbs. A spectral seismic profile across a paleoseismogenic scarp and one of the faults is presented. The magnitudes of vertical and horizontal fault movements are measured based on the displacement of rocks in the marker horizon. The vertical fault planes are studied, revealing their genetic relationship with thrust faults as the development of a single shear zone. Several types of shear fault zones are identified. The Yukki-Toksovskaya zone faults are identified as sinistral strike-slip faults. A preliminary estimate of horizontal movement rates along the faults in the Yukki-Toksovskaya zone is made. It is proposed to use the Yukki-Toksovskaya fault zone territory as a testing ground for studying Holocene paleoearthquakes.