Seismic convolutions in the Quaternary deposits of Lake Sevan, Armenia

The aim of the study is to detect deformations in the soft sediments in a tectonically active area (the Armenian Highland) and to examine the significance of the deformations as paleoseismicity indicators. Deformations in the form of pillows, pockets, sharp waves, and ovoids are exposed in the Sevan basin, within interbedded shallow lacustrine, beach, and fluvial sediments. Also, broken beds and low-amplitude thrusts are observed. Eight field criteria for assigning soft-sediment deformations to paleoseismic triggering provide strong evidence for the seismic origin of the deformations. According to the local relative stratigraphic scale, the Sevan seismites are of Pleistocene–Holocene age.